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Find video protocols related to scientific articles indexed in Pubmed.
Epithelial dysplasia of the stomach with gastric immunophenotype shows features of biological aggressiveness.
Gastric Cancer
PUBLISHED: 08-22-2014
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Gastric dysplasia is classified as adenomatous/type I (intestinal phenotype) and foveolar or pyloric/type II (gastric phenotype) according to morphological (architectural and cytological) features. The immunophenotypic classification of dysplasia, based on the expression of the mucins, CD10 and CDX2, recognizes the following immunophenotypes: intestinal (MUC2, CD10, and CDX2); gastric (MUC5AC and/or MUC6, absence of CD10, and absent or low expression of CDX2); hybrid (gastric and intestinal markers); and null.
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Effects of short-term propofol and dexmedetomidine on pulmonary morphofunction and biological markers in experimental mild acute lung injury.
Respir Physiol Neurobiol
PUBLISHED: 08-19-2014
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We evaluated whether the short-term use of dexmedetomidine and propofol may attenuate inflammatory response and improve lung morphofunction in experimental acute lung injury (ALI). Thirty-six Wistar rats were randomly divided into five groups. Control (C) and ALI animals received sterile saline solution and Escherichia coli lipopolysaccharide by intraperitoneal injection respectively. After 24h, ALI animals were randomly treated with dexmedetomidine, propofol, or thiopental sodium for 1h. Propofol reduced static lung elastance and resistive pressure and was associated with less alveolar collapse compared to thiopental sodium and dexmedetomidine. Dexmedetomidine improved oxygenation, but did not modify lung mechanics or histology. Propofol was associated with lower IL (interleukin)-6 and IL-1? expression, whereas dexmedetomidine led to reduced inducible nitric oxide (iNOS) and increased nuclear factor erythroid 2-related factor 2 (Nrf2) expression in lung tissue compared to thiopental sodium. In conclusion, in this model of mild ALI, short-term use of dexmedetomidine and propofol led to different functional effects and activation of biological markers associated with pulmonary inflammation.
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Immunohistochemical molecular phenotypes of gastric cancer based on SOX2 and CDX2 predict patient outcome.
BMC Cancer
PUBLISHED: 05-21-2014
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Gastric cancer remains a serious health concern worldwide. Patients would greatly benefit from the discovery of new biomarkers that predict outcome more accurately and allow better treatment and follow-up decisions. Here, we used a retrospective, observational study to assess the expression and prognostic value of the transcription factors SOX2 and CDX2 in gastric cancer.
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Differentiation reprogramming in gastric intestinal metaplasia and dysplasia: role of SOX2 and CDX2.
Histopathology
PUBLISHED: 04-14-2014
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Intestinal metaplasia (IM), which results from de-novo expression of CDX2, and dysplasia are precursor lesions of gastric cancer that are associated with an increased risk for cancer development. There is much evidence suggesting a role for the transcription factor SOX2 in gastric differentiation. The aim of this study was to attempt to establish the relationship of SOX2 with CDX2 and with the differentiation reprogramming that characterizes gastric carcinogenesis, to assess their involvement in IM and dysplasia.
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Evaluation of colon cancer histomorphology: a comparison between formalin and PAXgene tissue fixation by an international ring trial.
Virchows Arch.
PUBLISHED: 04-10-2014
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The aim of our study was to evaluate the quality of histo- and cytomorphological features of PAXgene-fixed specimens and their suitability for histomorphological classification in comparison to standard formalin fixation. Fifteen colon cancer tissues were collected, divided into two mirrored samples and either formalin fixed (FFPE) or PAXgene fixed (PFPE) before paraffin embedding. HE- and PAS-stained sections were scanned and evaluated in a blinded, randomised ring trial by 20 pathologists from Europe and the USA using virtual microscopy. The pathologists evaluated histological grading, histological subtype, presence of adenoma, presence of lymphovascular invasion, quality of histomorphology and quality of nuclear features. Statistical analysis revealed that the reproducibility with regard to grading between both fixation methods was rather satisfactory (weighted kappa statistic (k w)?=?0.73 (95 % confidence interval (CI), 0.41-0.94)), with a higher agreement between the reference evaluation and the PFPE samples (k w?=?0.86 (95 % CI, 0.67-1.00)). Independent from preservation method, inter-observer reproducibility was not completely satisfactory (k w?=?0.60). Histomorphological quality parameters were scored equal or better for PFPE than for FFPE samples. For example, overall quality and nuclear features, especially the detection of mitosis, were judged significantly better for PFPE cases. By contrast, significant retraction artefacts were observed more frequently in PFPE samples. In conclusion, our findings suggest that the PAXgene Tissue System leads to excellent preservation of histomorphology and nuclear features of colon cancer tissue and allows routine morphological diagnosis.
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Evaluation of clinico-pathological features and Helicobacter pylori infection in gastric inflammatory fibroid polyps.
Virchows Arch.
PUBLISHED: 04-06-2014
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Inflammatory fibroid polyps are rare mesenchymal lesions. The frequency of Helicobacter pylori infection in the gastric mucosa overlying inflammatory fibroid polyps and its relation with the histologic features of the polyps are undetermined. The clinico-pathological features of inflammatory fibroid polyps, the frequency of Helicobacter pylori infection in the overlying gastric mucosa, and its putative impact on the phenotype of the polyps were evaluated. Gastric inflammatory fibroid polyps diagnosed in our Hospital from 1998 to 2012 were reviewed and the histological. The histological sections were stained with hematoxylin and eosin and modified Giemsa for the evaluation of Helicobacter pylori infection. Inconclusive cases were further analyzed by immunohistochemistry with anti-Helicobacter pylori antibody. Diagnosis was confirmed in 54 polyps, 85 % developed in females, mean age 63?±?11 years. Most polyps were sessile (74 %), with a mean size of 15?±?12 mm, 96 % were located in the antrum and 85 % were removed by snare polypectomy. Helicobacter pylori infection was identified in 48 % of the polyps. Most inflammatory fibroid polyps developed in the submucosa, and mucosal extension was observed in 96 % of the cases. Chronic gastritis was observed in all cases (63 % with activity, 31 % with intestinal metaplasia, and 61 % with foveolar hyperplasia). Erosion and ulceration of the overlying gastric mucosa was observed in 48 % and 11 % of the polyps, respectively. Onion skin features were present in 52 % of the polyps and were more frequently observed in cases without evidence of Helicobacter pylori infection. Background changes in gastric mucosa were not distinctive according to Helicobacter pylori infection. Chronic atrophic gastritis with intestinal metaplasia was associated with the presence of perivascular onion skin lesions. To our knowledge, this is the second largest series of gastric inflammatory fibroid polyps. Helicobacter pylori infection was identified in about half of the cases and was associated with a lower frequency of onion skin features in the polyps.
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Unmet needs and challenges in gastric cancer: the way forward.
Cancer Treat. Rev.
PUBLISHED: 02-22-2014
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Although the incidence of gastric cancer has fallen steadily in developed countries over the past 50 years, outcomes in Western countries remain poor, primarily due to the advanced stage of the disease at presentation. While earlier diagnosis would help to improve outcomes for patients with gastric cancer, better understanding of the biology of the disease is also needed, along with advances in therapy. Indeed, progress in the treatment of gastric cancer has been limited, mainly because of its genetic complexity and heterogeneity. As a result, there is an urgent need to apply precision medicine to the management of the disease in order to ensure that individuals receive the most appropriate treatment. This article suggests a number of strategies that may help to accelerate progress in treating patients with gastric cancer. Incorporation of some of these approaches could help to improve the quality of life and survival for patients diagnosed with the disease. Standardisation of care across Europe through expansion of the European Registration of Cancer Care (EURECCA) registry - a European cancer audit that aims to improve quality and decrease variation in care across the region - may also be expected to lead to improved outcomes for those suffering from this common malignancy.
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Biomarkers for gastric cancer: prognostic, predictive or targets of therapy?
Virchows Arch.
PUBLISHED: 02-01-2014
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Gastric cancer is an aggressive disease often diagnosed at an advanced stage. Despite improvements in surgical and adjuvant treatment approaches, gastric cancer remains a global public health problem with a 5-year overall survival of less than 25 %. This is a heterogeneous disease, both in terms of biology and genetics, and many prognostic biomarkers have been pointed out in the literature; nevertheless, their application remains debatable. In this review, we opted to give relevance to those biomarkers that have been the subject of studies with significant statistical power, which have been replicated and have been/are in targeted therapy clinical trials and, which as a consequence, have their prognostic and/or predictive value established. Some gastric cancer biomarkers that may help in defining the course of treatment are also discussed. Accepted practical guidelines, wet-lab protocols for the detection of these biomarkers, as well as ongoing and completed clinical trials have been compiled. In summary, clinical approaches based on the combination of correct staging with targeted and conventional systemic therapies may improve gastric cancer patients' outcome, but are only in their infancy. Some major challenges in identifying reliable prognostic/predictive biomarkers are individual genetic variation and tumour heterogeneity that often influence response to therapy and drug resistance. Prognostic and predictive biomarkers may nevertheless be extremely valuable to correctly stratify gastric cancer patients for treatment and, ultimately, improve survival.
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Genetic variants in the IL1A gene region contribute to intestinal-type gastric carcinoma susceptibility in European populations.
Int. J. Cancer
PUBLISHED: 01-16-2014
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The most studied genetic susceptibility factors involved in gastric carcinoma (GC) risk are polymorphisms in the inflammation-linked genes interleukin 1 (IL1) B and IL1RN. Despite the evidence pointing to the IL1 region, definite functional variants reproducible across populations of different genetic background have not been discovered so far. A high density linkage disequilibrium (LD) map of the IL1 gene cluster was established using HapMap to identify haplotype tagSNPs. Eighty-seven SNPs were genotyped in a Portuguese case-control study (358 cases, 1,485 controls) for the discovery analysis. A replication study, including a subset of those tagSNPs (43), was performed in an independent analysis (EPIC-EurGast) containing individuals from 10 European countries (365 cases, 1284 controls). Single SNP and haplotype block associations were determined for GC overall and anatomopathological subtypes. The most robust association was observed for SNP rs17042407, 16Kb upstream of the IL1A gene. Although several other SNP associations were observed, only the inverse association of rs17042407 allele C with GC of the intestinal type was observed in both studies, retaining significance after multiple testing correction (p?=?0.0042) in the combined analysis. The haplotype analysis of the IL1A LD block in the combined dataset revealed the association between a common haplotype carrying the rs17042407 variant and GC, particularly of the intestinal type (p?=?3.1 × 10(-5) ) and non cardia localisation (p?=?4.6 × 10(-3) ). These results confirm the association of IL1 gene variants with GC and reveal a novel SNP and haplotypes in the IL1A region associated with intestinal type GC in European populations.
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Tactoid Body Features in Colon Mucosal Schwann Cell Hamartoma.
Int. J. Surg. Pathol.
PUBLISHED: 08-30-2013
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Background. Mesenchymal colorectal polyps are uncommon lesions, particularly those of neurogenic origin. We describe a mucosal Schwann cell hamartoma of the colon with tactoid features, so far reported in peripheral nerve sheath tumours, and address its differential diagnosis and clinical implications. Case presentation. A 72-year-old man underwent screening colonoscopy that presented a 5-mm polyp on distal sigmoid. Histologically, it displayed a lesion in the lamina propria comprising oval structures with tactoid features and bland spindle cells, entrapping adjacent crypts. No ganglion cells were seen. Spindle cells expressed only S-100 protein and vimentin. Discussion. Mucosal Schwann cell hamartoma was recently recognized as distinct from common (submucosal) colorectal Schwannomas and so far not associated to inherited syndromes. Thus, it should be considered in the differential diagnosis of look-alike lesions (eg, ganglioneuroma, neuroma, and neurofibroma) that may occur in the setting of inherited syndromes such as Cowden syndrome, multiple endocrine neoplasia-2B, and type 1 neurofibromatosis.
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First-degree relatives of early-onset gastric cancer patients show a high risk for gastric cancer: phenotype and genotype profile.
Virchows Arch.
PUBLISHED: 07-12-2013
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First-degree relatives (FDR) of early-onset gastric cancer (EOGC) is presumed to be a population with a distinct molecular and phenotypic profile, regarding the prevalence of gastric premalignant conditions and the association with Helicobacter pylori infection and host proinflammatory gene polymorphisms. A case-control study was conducted with FDR of EOGC patients (n?=?103) and age and gender matched controls (n?=?101; ranging from spouses to neighbors and dyspeptics). Upper endoscopy was performed, Operative Link on Gastritis Assessment (OLGA) system used for staging and H. pylori (cagA and vacA) and host IL1B-511, IL1RN intron2 VNTR and IFNGR1-56 genotyping. Seventy percent of cases showed atrophy, while 19 % presented with high-stage gastritis (OLGA stage III or IV) (p?
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Gastric cancer: adding glycosylation to the equation.
Trends Mol Med
PUBLISHED: 05-30-2013
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Gastric cancer has a high incidence and mortality, so there is a pressing need to understand the underlying molecular mechanisms in order to discover novel biomarkers. Glycosylation alterations are frequent during gastric carcinogenesis and cancer progression. This review describes the role of glycans from the initial steps of the carcinogenesis process, in which Helicobacter pylori adheres to host mucosa glycans and modulates the glycophenotype, as well as how glycans interfere with epithelial cell adhesion by modulating epithelial cadherin functionality in gastric cancer progression. Other mechanisms regulating gastric cancer malignant behavior are discussed, such as increased sialylation interfering with key signaling pathways and integrin glycosylation leading to an invasive phenotype. Applications of these glycosylation alterations in the clinical management of gastric cancer patients are discussed.
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E-cadherin and adherens-junctions stability in gastric carcinoma: functional implications of glycosyltransferases involving N-glycan branching biosynthesis, N-acetylglucosaminyltransferases III and V.
Biochim. Biophys. Acta
PUBLISHED: 05-15-2013
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E-cadherin is a cell-cell adhesion molecule and the dysfunction of which is a common feature of more than 70% of all invasive carcinomas, including gastric cancer. Mechanisms behind the loss of E-cadherin function in gastric carcinomas include mutations and silencing at either the DNA or RNA level. Nevertheless, in a high percentage of gastric carcinoma cases displaying E-cadherin dysfunction, the mechanism responsible for E-cadherin dysregulation is unknown. We have previously demonstrated the existence of a bi-directional cross-talk between E-cadherin and two major N-glycan processing enzymes, N-acetylglucosaminyltransferase-III or -V (GnT-III or GnT-V).
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Validation of a fluorescence in situ hybridization method using peptide nucleic acid probes for detection of Helicobacter pylori clarithromycin resistance in gastric biopsy specimens.
J. Clin. Microbiol.
PUBLISHED: 04-17-2013
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Here, we evaluated a previously established peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) method as a new diagnostic test for Helicobacter pylori clarithromycin resistance detection in paraffin-embedded gastric biopsy specimens. Both a retrospective study and a prospective cohort study were conducted to evaluate the specificity and sensitivity of a PNA-FISH method to determine H. pylori clarithromycin resistance. In the retrospective study (n = 30 patients), full agreement between PNA-FISH and PCR-sequencing was observed. Compared to the reference method (culture followed by Etest), the specificity and sensitivity of PNA-FISH were 90.9% (95% confidence interval [CI], 57.1% to 99.5%) and 84.2% (95% CI, 59.5% to 95.8%), respectively. In the prospective cohort (n = 93 patients), 21 cases were positive by culture. For the patients harboring clarithromycin-resistant H. pylori, the method showed sensitivity of 80.0% (95% CI, 29.9% to 98.9%) and specificity of 93.8% (95% CI, 67.7% to 99.7%). These values likely represent underestimations, as some of the discrepant results corresponded to patients infected by more than one strain. PNA-FISH appears to be a simple, quick, and accurate method for detecting H. pylori clarithromycin resistance in paraffin-embedded biopsy specimens. It is also the only one of the methods assessed here that allows direct and specific visualization of this microorganism within the biopsy specimens, a characteristic that allowed the observation that cells of different H. pylori strains can subsist in very close proximity in the stomach.
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Radiofrequency ablation for the treatment of gastric dysplasia: a pilot experience in three patients.
Eur J Gastroenterol Hepatol
PUBLISHED: 03-21-2013
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Different endoscopic techniques such as endoscopic mucosal resection, endoscopic submucosal dissection, argon-plasma coagulation, and photodynamic therapy have been used in the treatment of gastric dysplasia. Radiofrequency ablation (RFA) has become a recognized tool in the treatment of dysplastic Barretts esophagus, but its use in gastric dysplasia has not yet been studied. We aim to describe three cases of RFA treatment in patients with persistent dysplastic gastric mucosa confirmed by consensus of two expert gastrointestinal pathologists. In each patient, two catheter-based RFA procedures were performed 8 weeks apart in an outpatient setting. Although each patient reported minor epigastric pain after RFA, there were no major complications such as bleeding, perforation, stricture, or the need for hospitalization. Endoscopic follow-up with extensive biopsy sampling 2, 4, 6, 12, and 18 months after the last RFA revealed negative results for dysplasia in all patients. These results suggest that RFA may be considered in the treatment of gastric dysplasia. The confirmation of these data with a large series can lead to a change in the paradigm of gastric dysplasia management.
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E-cadherin alterations in hereditary disorders with emphasis on hereditary diffuse gastric cancer.
Prog Mol Biol Transl Sci
PUBLISHED: 03-14-2013
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The only gastric cancer (GC) syndrome with a proven inherited defect is designated as hereditary diffuse gastric cancer (HDGC) and is caused by germline E-cadherin/CDH1 alterations. Other E-cadherin-associated hereditary disorders have been identified, encompassing HDGC families with or without cleft-lip/palate involvement, isolated early-onset diffuse GCs, and lobular breast cancer families without GC. To date, 141 probands harboring more than 100 different germline CDH1 alterations, mainly point mutations and large deletions, have been described in these different settings. A third of all HDGC families described so far carry recurrent CDH1 alterations. Full screening of CDH1 is recommended in patients fulfilling the HDGC criteria and total prophylactic gastrectomy is the only reliable intervention for carriers of pathogenic alterations. In this chapter, we discuss CDH1-associated syndromes, frequency and type of CDH1 germline alterations, clinical criteria, and guidelines for genetic counseling, molecular pathology, and available animal/cell line models of the disease.
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Polymorphisms of Helicobacter pylori signaling pathway genes and gastric cancer risk in the European Prospective Investigation into Cancer-Eurgast cohort.
Int. J. Cancer
PUBLISHED: 02-28-2013
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Helicobacter pylori is a recognized causal factor of noncardia gastric cancer (GC). Lipopolysaccharide and peptidoglycan of this bacterium are recognized by CD14, TLR4 and NOD2 human proteins, while NFKB1 activates the transcription of pro-inflammatory cytokines to elicit an immune response. Single nucleotide polymorphisms (SNPs) in these genes have been associated with GC in different populations. We genotyped 30 SNPs of these genes, in 365 gastric adenocarcinomas and 1,284 matched controls from the European Prospective Investigation into Cancer cohort. The association with GC and its histological and anatomical subtypes was analyzed by logistic regression and corrected for multiple comparisons. Using a log-additive model, we found a significant association between SNPs in CD14, NOD2 and TLR4 with GC risk. However, after applying the multiple comparisons tests only the NOD2 region remained significant (p = 0.009). Analysis according to anatomical subtypes revealed NOD2 and NFKB1 SNPs associated with noncardia GC and CD14 SNPs associated with cardia GC, while analysis according to histological subtypes showed that CD14 was associated with intestinal but not diffuse GC. The multiple comparisons tests confirmed the association of NOD2 with noncardia GC (p = 0.0003) and CD14 with cardia GC (p = 0.01). Haplotype analysis was in agreement with single SNP results for NOD2 and CD14 genes. From these results, we conclude that genetic variation in NOD2 associates with noncardia GC while variation in CD14 is associated with cardia GC.
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Transcription factor NRF2 protects mice against dietary iron-induced liver injury by preventing hepatocytic cell death.
J. Hepatol.
PUBLISHED: 01-11-2013
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The liver, being the major site of iron storage, is particularly exposed to the toxic effects of iron. Transcription factor NRF2 is critical for protecting the liver against disease by activating the transcription of genes encoding detoxification/antioxidant enzymes. We aimed to determine if the NRF2 pathway plays a significant role in the protection against hepatic iron overload.
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E-cadherin impairment increases cell survival through Notch-dependent upregulation of Bcl-2.
Hum. Mol. Genet.
PUBLISHED: 10-11-2011
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The role of E-cadherin in tumorigenesis has been attributed to its ability to suppress invasion and metastization. However, E-cadherin impairment may have a wider impact on tumour development. We have previously shown that overexpression of mutant human E-cadherin in Drosophila produces a phenotype characteristic of downregulated Notch. Hence, we hypothesized that Notch signalling may be influenced by E-cadherin and may mediate tumour development associated with E-cadherin deficiency. De novo expression of wild-type E-cadherin in two cellular models led to a significant decrease in the activity of the Notch pathway. In contrast, the ability to inhibit Notch-1 signalling was lost in cells transfected with mutant forms of E-cadherin. Increased Notch-1 activity in E-cadherin-deficient cells correlated with increased expression of Bcl-2, and increased resistance to apoptotic stimuli. After Notch-1 inhibition, E-cadherin-deficient cells were re-sensitized to apoptosis in a similar degree to wild-type E-cadherin cells. We also show that Notch-inhibiting drugs are able to significantly inhibit the growth of E-cadherin-deficient cells xenografted into nude mice. This effect was comparable with the one observed in animals treated with the chemotherapeutic agent taxol, a chemical inducer of cell death. In conclusion, our results show that aberrant Notch-1 activation, Bcl-2 overexpression and increased cell survival are likely to play a crucial role in neoplastic transformation associated with E-cadherin impairment. These findings highlight the possibility of new targeted therapeutical strategies for the treatment of tumours associated with E-cadherin inactivation.
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Metastatic cutaneous Crohns disease of the face: a case report and review of the literature.
Eur J Gastroenterol Hepatol
PUBLISHED: 09-09-2011
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Metastatic cutaneous Crohns disease is one of the most uncommon cutaneous extraintestinal manifestations. The face is the rarest location, with only eight cases described in the literature. We report a rare case of a young man with Crohns disease and two granulomatous lesions on the face in a nodular form. To the best of our knowledge, this is the first report of metastatic Crohns disease of the forehead with the features of nodules. A review of the literature concerning metastatic Crohns disease is also provided.
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Immunohistochemical diagnosis of Fabry nephropathy and localisation of globotriaosylceramide deposits in paraffin-embedded kidney tissue sections.
Virchows Arch.
PUBLISHED: 07-22-2011
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Fabry disease (FD) is a rare X-linked lysosomal storage disorder of glycosphingolipids, mostly globotriaosylceramide (Gb3). Proteinuric chronic kidney disease develops frequently, and recognition of Fabry nephropathy on a kidney biopsy may be the first clue to the underlying diagnosis. Since the accumulated glycosphingolipids are largely extracted by the paraffin-embedding procedure, the most characteristic feature of Fabry nephropathy on routine light microscopy (LM) is nonspecific cell vacuolization. To test whether residual Gb3 in kidney tissue might be exploited for the specific diagnosis of Fabry nephropathy, paraffin-embedded kidney biopsies of nine FD patients (one boy, four men, four women) and of a female carrier of a mild genetic mutation, with no evidence of Fabry nephropathy, were immunostained with an anti-Gb3 antibody. The adult biopsies were additionally co-stained with a lysosomal marker (anti-lysosomal-associated membrane protein 2 (anti-LAMP2) antibody). The distribution of Gb3 deposits was scored per cell type and compared to the histological scorings of glycosphingolipid inclusions on semi-thin sections. FD patients had residual Gb3 in all types of glomerular, tubular, interstitial and vascular kidney cells. The highest expression of LAMP2 was seen in tubular cells, but there were no meaningful associations between LAMP2 expression and prevalence of Gb3 deposits on different kidney cell types. The histological scorings of glycosphingolipid inclusions were relatively higher than the corresponding immunohistochemical scorings of Gb3 deposits. In the mildly affected female, Gb3 expression was limited to tubular cells, a pattern similar to controls. Gb3 immunostaining allows the specific diagnosis of Fabry nephropathy even in kidney biopsies routinely processed for LM.
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Oncogenic mutations in gastric cancer with microsatellite instability.
Eur. J. Cancer
PUBLISHED: 06-15-2011
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Mitogen-activated protein kinase (MAPK) cascade and phosphatidylinositol 3-kinase (PI3K) survival pathways are frequently activated in the progression of gastrointestinal malignancies. In this study, we aimed to determine the frequency of gene mutations in members of these pathways--Epithelial Growth Factor Receptor (EGFR), KRAS, BRAF, PIK3CA and MLK3 in a series of 63 gastric carcinomas with high levels of microsatellite instability (MSI).
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PNA-FISH as a new diagnostic method for the determination of clarithromycin resistance of Helicobacter pylori.
BMC Microbiol.
PUBLISHED: 02-23-2011
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Triple therapy is the gold standard treatment for Helicobacter pylori eradication from the human stomach, but increased resistance to clarithromycin became the main factor of treatment failure. Until now, fastidious culturing methods are generally the method of choice to assess resistance status. In this study, a new genotypic method to detect clarithromycin resistance in clinical samples, based on fluorescent in situ hybridization (FISH) using a set of peptide nucleic acid probes (PNA), is proposed.
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Kidney histologic alterations in ?-Galactosidase-deficient mice.
Virchows Arch.
PUBLISHED: 01-22-2011
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Fabry disease is a rare X-linked disorder caused by mutations in the ?-galactosidase gene (GLA), the resultant deficiency of lysosomal ?-galactosidase enzyme activity leading to systemic accumulation of globotriaosylceramide and other glycosphingolipids. GLA knockout mice ("Fabry mice") were generated as an animal model for Fabry disease but, as they do not manifest progressive chronic kidney disease (CKD), their relevance as a model for human Fabry nephropathy is uncertain. We evaluated the histological alterations in the kidneys of Fabry mice at different ages, as contrasted to those observed in wild-type mice. Furthermore, we compared the renal histological alterations of Fabry mice to the kidney pathology reported in patients with Fabry disease at comparable age ranges and across different CKD stages, using a scoring system that has been developed for Fabry nephropathy. Fabry mice are phenotypically different from wild-type mice, displaying progressive age-related accumulation of glycosphingolipids in all types of renal cells. There were no statistically significant differences between Fabry mice and Fabry patients in the prevalence of glycosphingolipid storage per renal cell type with the exceptions of mesangial (higher in humans) and proximal tubular cells (higher in mice). However, Fabry mice lack the nonspecific histological glomerulosclerotic and interstitial fibrotic renal lesions that best correlate with progressive CKD in Fabry patients, and do not develop large podocyte inclusions. We postulate that the elucidation of the mechanisms underlying these species differences, may contribute important clues to a better understanding of the pathogenesis of Fabry nephropathy.
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Menstrual and reproductive factors, exogenous hormone use, and gastric cancer risk in a cohort of women from the European Prospective Investigation Into Cancer and Nutrition.
Am. J. Epidemiol.
PUBLISHED: 11-04-2010
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The worldwide incidence of gastric adenocarcinoma (GC) is lower in women than in men. Furthermore, cancer patients treated with estrogens have been reported to have a lower subsequent risk of GC. The authors conducted a prospective analysis of menstrual and reproductive factors, exogenous hormone use, and GC in 335,216 women from the European Prospective Investigation Into Cancer and Nutrition, a cohort study of individuals aged 35-70 years from 10 European countries. After a mean follow-up of 8.7 years (through 2004), 181 women for whom complete exposure data were available developed GC. Adjusted hazard ratios and 95% confidence intervals were estimated using Cox proportional hazards models. All statistical tests were 2-sided. Women who had ovariectomy had a 79% increased risk of GC (based on 25 cases) compared with women who did not (hazard ratio = 1.79, 95% confidence interval: 1.15, 2.78). Total cumulative years of menstrual cycling was inversely associated with GC risk (fifth vs. first quintile: hazard ratio = 0.55, 95% confidence interval: 0.31, 0.98; P(trend) = 0.06). No other reproductive factors analyzed were associated with risk of GC. The results of this analysis provide some support for the hypothesis that endogenous ovarian sex hormones lower GC incidence in women.
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De novo expression of CD44 variants in sporadic and hereditary gastric cancer.
Lab. Invest.
PUBLISHED: 09-20-2010
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CD44 is the major ubiquitously expressed cell surface receptor for hyaluronate. The CD44 gene encodes several protein isoforms due to extensive alternative splicing and post-translational modifications. Some of these CD44 variable isoforms have been foreseen as key players in malignant transformation and their expression is highly restricted and highly specific, unlike the canonical CD44 standard isoform. In this study, we aimed at dissecting the mRNA splicing pattern of CD44 in normal stomach and gastric cancer (GC) cell lines (n=9) using cloning and quantitative mRNA amplification assays. Moreover, we assessed the RNA levels and protein expression pattern of relevant splicing forms in distinct premalignant and malignant gastric lesions (sporadic (n=43) and hereditary (n=3) forms) using real-time RT-PCR and immunohistochemistry. We also explored the association of CD44 and E-cadherin expression by immunohistochemistry, as E-cadherin has a pivotal functional role in GC. We established the pattern of CD44 variant forms in normal stomach and gastric malignancy. We observed that although exon v6-containing isoforms were rarely expressed in normal gastric mucosa, they became increasingly expressed both in gastric premalignant (hyperplastic polyps, complete and incomplete intestinal metaplasia, low- and high-grade dysplasia) and malignant lesions (cell lines derived from GCs, primary sporadic GCs and hereditary diffuse GCs (HDGCs)). Moreover, we verified that whenever E-cadherin expression was absent, exon v6-containing CD44 isoforms were overexpressed. The lack of expression of CD44 isoforms containing exon v6 in the surface and foveolar epithelia of normal stomach and, its de novo expression in premalignant, as well as in sporadic and hereditary malignant lesions of the stomach, pinpoint CD44 v6-containing isoforms as potential biomarkers for early transformation of the gastric mucosa. Further, our results raise the hypothesis of using CD44v6 as a marker of early invasive intramucosal carcinoma in HDGC CDH1 mutation carriers that lack CDH1 expression in their tumors.
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Hereditary diffuse gastric cancer: updated consensus guidelines for clinical management and directions for future research.
J. Med. Genet.
PUBLISHED: 07-02-2010
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25-30% of families fulfilling the criteria for hereditary diffuse gastric cancer have germline mutations of the CDH1 (E-cadherin) gene. In light of new data and advancement of technologies, a multidisciplinary workshop was convened to discuss genetic testing, surgery, endoscopy and pathology reporting. The updated recommendations include broadening of CDH1 testing criteria such that: histological confirmation of diffuse gastric criteria is only required for one family member; inclusion of individuals with diffuse gastric cancer before the age of 40 years without a family history; and inclusion of individuals and families with diagnoses of both diffuse gastric cancer (including one before the age of 50 years) and lobular breast cancer. Testing is considered appropriate from the age of consent following counselling and discussion with a multidisciplinary team. In addition to direct sequencing, large genomic rearrangements should be sought. Annual mammography and breast MRI from the age of 35 years is recommended for women due to the increased risk for lobular breast cancer. In mutation positive individuals prophylactic total gastrectomy at a centre of excellence should be strongly considered. Protocolised endoscopic surveillance in centres with endoscopists and pathologists experienced with these patients is recommended for: those opting not to have gastrectomy, those with mutations of undetermined significance, and in those families for whom no germline mutation is yet identified. The systematic histological study of prophylactic gastrectomies almost universally shows pre-invasive lesions including in situ signet ring carcinoma with pagetoid spread of signet ring cells. Expert histopathological confirmation of these early lesions is recommended.
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C/EBP alpha expression is associated with homeostasis of the gastric epithelium and with gastric carcinogenesis.
Lab. Invest.
PUBLISHED: 04-12-2010
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Transcription factors from the CCAAT/enhancer-binding protein (C/EBP) family are fundamental for the control of differentiation and proliferation of many adult tissues. C/EBP alpha has a crucial role in inducing terminal differentiation and is an established tumor suppressor gene in several cancer models. The objective of this study was to analyze the putative role of C/EBP alpha in gastric carcinoma (GC). We analyzed the expression of C/EBP alpha in normal and neoplastic gastric tissues, and assessed the role of C/EBP alpha on proliferation and differentiation of GC cells. In normal gastric mucosa, C/EBP alpha is expressed in the foveolar epithelium and co-localizes with the gastric differentiation marker trefoil factor 1 (TFF1). The expression of C/EBP alpha was found to be lost in 30% of GC cases. To evaluate the role of C/EBP alpha in cell proliferation and differentiation, we transfected GC cells with a full-length C/EBP alpha protein. We observed a significant decrease in proliferation in C/EBP alpha-transfected cells. This was accompanied by a decrease in Cyclin D1, an increase in P27 expression, and an increased expression of TFF1. Finally, we showed that inhibition of the Ras/MAPK pathway leads to increased C/EBP alpha and TFF1 expression, and decreased cell proliferation and cyclin D1 expression in GC cells. Our results suggest that C/EBP alpha (together with other members of the C/EBP family) has an active role in the control of differentiation and proliferation in normal gastric mucosa. In GC, loss of C/EBP alpha may be associated with the switch from a cellular differentiation to a cellular proliferation program, presumably as a consequence of Ras/MAPK pathway activation.
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Helicobacter pylori colonization of the adenotonsillar tissue: fact or fiction?
Int. J. Pediatr. Otorhinolaryngol.
PUBLISHED: 03-23-2010
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The transmission of the gastric pathogen Helicobacter pylori involves the oral route. Molecular techniques have allowed the detection of H. pylori DNA in samples of the oral cavity, although culture of H. pylori from these type of samples has been sporadic. Studies have tried to demonstrate the presence of H. pylori in adenotonsillar tissue, with contradictory results. Our aim was to clarify whether the adenotonsillar tissue may constitute an extra gastric reservoir for H. pylori.
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MSI phenotype and MMR alterations in familial and sporadic gastric cancer.
Int. J. Cancer
PUBLISHED: 03-03-2010
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Microsatellite instability (MSI) is a major pathway involved in gastric carcinogenesis occurring in 20% of gastric cancer (GC). However, it is not clear whether MSI phenotype preferentially occurs in the sporadic or familial GC, when stringent inclusion criteria are used. The aim of this study was to compare the frequency of MSI and hypermethylation of MLH1 promoter in a large series of familial GC patients (non-HNPCC and non-CDH1-related) and sporadic cases. Additionally, we analysed the immunoexpression of MMR proteins in a fraction of cases. Overall, the frequency of familial GC was 7.1%, and the frequency of hereditary tumours was 4.6%. MSI phenotype and MLH1 hypermethylation frequencies were not statistical different between familial and sporadic GC settings. Further, the MSI phenotype was not associated with any clinico-pathological features studied in the familial GC setting, whereas in the sporadic setting, it was associated with older age, female gender and intestinal histotype. Using our stringent Amsterdam-based clinical criteria to select familial GC (number of cases, age of onset), we verified that sporadic and familial cases differed in gender but shared histopathological features. We verified that the frequency of MSI was similar in familial and sporadic GC settings, demonstrating that this molecular phenotype is not a hallmark of familial GC in contrast to what is verified in HNPCC. Moreover, we observed that the frequency of MLH1 hypermethylation is similar in sporadic and familial cases suggesting that in both settings MSI is not associated to MMR genetic alterations but in contrast to epigenetic deregulation.
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Vitamins B2 and B6 and genetic polymorphisms related to one-carbon metabolism as risk factors for gastric adenocarcinoma in the European prospective investigation into cancer and nutrition.
Cancer Epidemiol. Biomarkers Prev.
PUBLISHED: 01-09-2010
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B vitamins and polymorphisms in genes coding for enzymes involved in one-carbon metabolism may affect DNA synthesis and methylation and thereby be implicated in carcinogenesis. Previous data on vitamins B2 and B6 and genetic polymorphisms other than those involving MTHFR as risk factors for gastric cancer (GC) are sparse and inconsistent. In this case-control study nested within the European Prospective Investigation into Cancer and Nutrition cohort, cases (n = 235) and controls (n = 601) were matched for study center, age, sex, and time of blood sampling. B2 and B6 species were measured in plasma, and the sum of riboflavin and flavin mononucleotide was used as the main exposure variable for vitamin B2 status, whereas the sum of pyridoxal 5-phosphate, pyridoxal, and 4-pyridoxic acid was used to define vitamin B6 status. In addition, we determined eight polymorphisms related to one-carbon metabolism. Relative risks for GC risk were calculated with conditional logistic regression, adjusted for Helicobacter pylori infection status and smoking status. Adjusted relative risks per quartile (95% confidence interval, P(trend)) were 0.85 (0.72-1.01, 0.06) for vitamin B2 and 0.78 (0.65-0.93, <0.01) for vitamin B6. Both relations were stronger in individuals with severe chronic atrophic gastritis. The polymorphisms were not associated with GC risk and did not modify the observed vitamin-cancer associations. In summary, results from this large European cohort study showed an inverse association between vitamin B2 and GC risk, which is borderline significant, and a significant inverse association between vitamin B6 and GC risk.
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Clear cell change in colonic polyps.
Int. J. Surg. Pathol.
PUBLISHED: 12-23-2009
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In this study, the pathogenesis of clear cell change in colorectal epithelial lesions was studied. A total of 4 cases of clear cell change (1 hyperplasic polyp and 3 adenomas) were characterized using histochemistry, immunohistochemistry, and electron microscopy. All lesions developed in the left colon. In all, 1 adenoma with clear cell dysplastic glands progressed to adenocarcinoma without clear cell change. Clear cell cytoplasmatic vacuoles were negative for glycogen and mucins (MUC 2, MUC 5AC). Ki-67 LI in clear cell adenoma components was lower than in common adenoma components of the same dysplasia grades (while p53 and beta-catenin were similarly expressed). Ultrastructural features of clear cell change showed features of lipid-like material. Clear cell change is found in hyperplastic and neoplastic lesions of the colon and is not due to the accumulation of glycogen or mucins. A degenerative nature of clear cell change is suggested by the demonstration of lipid-like material in the vacuoles of clear cells.
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Mixed lineage kinase 3 gene mutations in mismatch repair deficient gastrointestinal tumours.
Hum. Mol. Genet.
PUBLISHED: 12-02-2009
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Mixed lineage kinase 3 (MLK3) is a serine/threonine kinase, regulating MAPkinase signalling, in which cancer-associated mutations have never been reported. In this study, 174 primary gastrointestinal cancers (48 hereditary and 126 sporadic forms) and 7 colorectal cancer cell lines were screened for MLK3 mutations. MLK3 mutations were significantly associated with MSI phenotype in primary tumours (P = 0.0005), occurring in 21% of the MSI carcinomas. Most MLK3 somatic mutations identified were of the missense type (62.5%) and more than 80% of them affected evolutionarily conserved residues. A predictive 3D model points to the functional relevance of MLK3 missense mutations, which cluster in the kinase domain. Further, the model shows that most of the altered residues in the kinase domain probably affect MLK3 scaffold properties, instead of its kinase activity. MLK3 missense mutations showed transforming capacity in vitro and cells expressing the mutant gene were able to develop locally invasive tumours, when subcutaneously injected in nude mice. Interestingly, in primary tumours, MLK3 mutations occurred in KRAS and/or BRAF wild-type carcinomas, although not being mutually exclusive genetic events. In conclusion, we have demonstrated for the first time the presence of MLK3 mutations in cancer and its association to mismatch repair deficiency. Further, we demonstrated that MLK3 missense mutations found in MSI gastrointestinal carcinomas are functionally relevant.
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Hereditary gastric cancer.
Best Pract Res Clin Gastroenterol
PUBLISHED: 05-06-2009
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Gastric cancer is a heterogeneous and highly prevalent disease, being the fourth most common cancer and the second leading cause of cancer associated death worldwide. Most cases are sporadic and familial clustering is observed in about 10% of the cases. Hereditary gastric cancer accounts for a very low percentage of cases (1-3%) and a single hereditary syndrome - Hereditary Diffuse Gastric Cancer (HDGC) - has been characterised. Among families that fulfil the clinical criteria for HDGC, about 40% carry CDH1 germline mutations, the genetic cause of the others being unknown. The management options for CDH1 asymptomatic germline carriers are intensive endoscopic surveillance and prophylactic gastrectomy. In this chapter we review the pathophysiology and clinicopathological features of HDGC and discuss issues related with genetic testing and management of family members.
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The role of N-acetylglucosaminyltransferase III and V in the post-transcriptional modifications of E-cadherin.
Hum. Mol. Genet.
PUBLISHED: 04-29-2009
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It has long been recognized that E-cadherin dysfunction is a major cause of epithelial cell invasion. However, very little is known about the post-transcriptional modifications of E-cadherin and its role in E-cadherin mediated tumor progression. N-acetylglucosaminyltransferase III (GnT-III) catalyzes the formation of a bisecting GlcNAc structure in N-glycans, and has been pointed as a metastasis suppressor. N-acetylglucosaminyltransferase V (GnT-V) catalyzes the addition of beta1,6 GlcNAc branching of N-glycans, and has been associated to increase metastasis. The regulatory mechanism between E-cadherin expression and the remodeling of its oligosaccharides structures by GnT-III and GnT-V were explored in this study. We have demonstrated that wild-type E-cadherin regulates MGAT3 gene transcription resulting in increased GnT-III expression. We also showed that GnT-III and GnT-V competitively modified E-cadherin N-glycans. The GnT-III knockdown cells revealed a membrane de-localization of E-cadherin leading to its cytoplasmic accumulation. Further, the GnT-III knockdown cells also caused modifications of E-cadherin N-glycans catalyzed by GnT-III and GnT-V. Altogether our results have clarified the existence of a bidirectional crosstalk between E-cadherin and GnT-III/GnT-V that was, for the first time, reproduced in an in vivo model. This study opens new insights into the post-transcriptional modifications of E-cadherin in its biological function, in a tumor context.
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Helicobacter pylori infection induces genetic instability of nuclear and mitochondrial DNA in gastric cells.
Clin. Cancer Res.
PUBLISHED: 04-21-2009
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Helicobacter pylori is a major cause of gastric carcinoma. To investigate a possible link between bacterial infection and genetic instability of the host genome, we examined the effect of H. pylori infection on known cellular repair pathways in vitro and in vivo. Moreover, various types of genetic instabilities in the nuclear and mitochondrial DNA (mtDNA) were examined.
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Role of the epithelial-mesenchymal transition regulator Slug in primary human cancers.
Front Biosci (Landmark Ed)
PUBLISHED: 03-11-2009
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Epithelial-mesenchymal-transition (EMT) is a crucial process during morphogenesis of multi-cellular organisms. EMT not only is a normal developmental process but also plays a role in tumor invasion and metastasis. Indeed, molecules involved in EMT, such as the transcription factor and E-cadherin repressor Slug (SNAI2), have recently been demonstrated to be important for cancer cells to down-regulate epithelial markers and up-regulate mesenchymal markers in order to become motile and invasive. Here we summarize major studies focusing on Slug expression in human tumor samples. We review a total of 13 studies involving 1150 cases from 9 different types of tumors. It is becoming clear that this transcription factor plays a role in the progression of some tumor types, including breast and gastric cancer. Interestingly, Slug expression is not always associated with down-regulation of E-cadherin. The mode of action, the signaling pathways involved in its regulation, and the interplay with other EMT regulators need to be addressed in future studies in order to fully understand Slugs role in tumor progression.
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Quantification of epigenetic and genetic 2nd hits in CDH1 during hereditary diffuse gastric cancer syndrome progression.
Gastroenterology
PUBLISHED: 02-16-2009
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Hereditary diffuse gastric cancer (HDGC) families carry CDH1 heterozygous germline mutations; their tumors acquire complete CDH1 inactivation through "2nd-hit" mechanisms. Most frequently, this occurs via promoter hypermethylation (epigenetic modification), and less frequently via CDH1 mutations and loss of heterozygosity (LOH). We quantified the different 2nd hits in CDH1 occurring in neoplastic lesions from HDGC patients.
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A TARBP2 mutation in human cancer impairs microRNA processing and DICER1 function.
Nat. Genet.
PUBLISHED: 02-15-2009
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microRNAs (miRNAs) are small noncoding RNAs that regulate gene expression by targeting messenger RNA (mRNA) transcripts. Recently, a miRNA expression profile of human tumors has been characterized by an overall miRNA downregulation. Explanations for this observation include a failure of miRNA post-transcriptional regulation, transcriptional silencing associated with hypermethylation of CpG island promoters and miRNA transcriptional repression by oncogenic factors. Another possibility is that the enzymes and cofactors involved in miRNA processing pathways may themselves be targets of genetic disruption, further enhancing cellular transformation. However, no loss-of-function genetic alterations in the genes encoding these proteins have been reported. Here we have identified truncating mutations in TARBP2 (TAR RNA-binding protein 2), encoding an integral component of a DICER1-containing complex, in sporadic and hereditary carcinomas with microsatellite instability. The presence of TARBP2 frameshift mutations causes diminished TRBP protein expression and a defect in the processing of miRNAs. The reintroduction of TRBP in the deficient cells restores the efficient production of miRNAs and inhibits tumor growth. Most important, the TRBP impairment is associated with a destabilization of the DICER1 protein. These results provide, for a subset of human tumors, an explanation for the observed defects in the expression of mature miRNAs.
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Juvenile polyps have gastric differentiation with MUC5AC expression and downregulation of CDX2 and SMAD4.
Histochem. Cell Biol.
PUBLISHED: 02-12-2009
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CDX2 is a homeobox transcription factor that works as a master gene in intestinal differentiation, both in the colon and in aberrant locations such as intestinal metaplasia (IM) of the stomach. Transgenic mice with Cdx2 expression in the stomach develop IM and Cdx2(+/-) mice develop hamartomatous polyps in the colon presenting gastric differentiation. We previously observed regulation of CDX2 by the BMP/SMAD pathway in the gastric context. Here, we hypothesized that juvenile polyps, which are hamartomatous polyps caused by mutations in members of the BMP/SMAD pathway, might recapitulate the gastric differentiation observed in Cdx2(+/-) mice due to SMAD4 and CDX2 downregulation. We characterized SMAD4 and CDX2 expression in a series of 18 solitary juvenile polyps and 2 polyps from juvenile polyposis (JP) patients, one with a germline SMAD4 mutation and one with a germline BMPRIA mutation, as well as the expression of an intestinal differentiation marker, MUC2 (by immunohistochemistry and in situ hybridization), and gastric differentiation markers, MUC5AC and MUC6 (by immunohistochemistry). We observed that juvenile polyps have a heterogeneous expression of CDX2, MUC2 and SMAD4, with negative areas, and 15 of the 18 solitary polyps and the JP case with SMAD4 mutation exhibit de novo expression of MUC5AC but not MUC6. In conclusion, juvenile polyps have gastric transdifferentiation associated with downregulation of CDX2 and SMAD4, lending support to the role of the BMP/SMAD pathway in CDX2 regulation.
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History, pathogenesis, and management of familial gastric cancer: original study of John XXIIIs family.
Biomed Res Int
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Hereditary diffuse gastric cancer is associated with the E-cadherin germline mutations, but genetic determinants have not been identified for familial intestinal gastric carcinoma. The guidelines for hereditary diffuse gastric cancer are clearly established; however, there are no defined recommendations for the management of familial intestinal gastric carcinoma.
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Guideline on the requirements of external quality assessment programs in molecular pathology.
Virchows Arch.
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Molecular pathology is an integral part of daily diagnostic pathology and used for classification of tumors, for prediction of prognosis and response to therapy, and to support treatment decisions. For these reasons, analyses in molecular pathology must be highly reliable and hence external quality assessment (EQA) programs are called for. Several EQA programs exist to which laboratories can subscribe, but they vary in scope, number of subscribers, and execution. The guideline presented in this paper has been developed with the purpose to harmonize EQA in molecular pathology. It presents recommendations on how an EQA program should be organized, provides criteria for a reference laboratory, proposes requirements for EQA test samples, and defines the number of samples needed for an EQA program. Furthermore, a system for scoring of the results is proposed as well as measures to be taken for poorly performing laboratories. Proposals are made regarding the content requirements of an EQA report and how its results should be communicated. Finally, the need for an EQA database and a participant manual are elaborated. It is the intention of this guideline to improve EQA for molecular pathology in order to provide more reliable molecular analyses as well as optimal information regarding patient selection for treatment.
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Serrated polyps of the colon: how reproducible is their classification?
Virchows Arch.
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For several years, the lack of consensus on definition, nomenclature, natural history, and biology of serrated polyps (SPs) of the colon has created considerable confusion among pathologists. According to the latest WHO classification, the family of SPs comprises hyperplastic polyps (HPs), sessile serrated adenomas/polyps (SSA/Ps), and traditional serrated adenomas (TSAs). The term SSA/P with dysplasia has replaced the category of mixed hyperplastic/adenomatous polyps (MPs). The present study aimed to evaluate the reproducibility of the diagnosis of SPs based on currently available diagnostic criteria and interactive consensus development. In an initial round, H&E slides of 70 cases of SPs were circulated among participating pathologists across Europe. This round was followed by a consensus discussion on diagnostic criteria. A second round was performed on the same 70 cases using the revised criteria and definitions according to the recent WHO classification. Data were evaluated for inter-observer agreement using Kappa statistics. In the initial round, for the total of 70 cases, a fair overall kappa value of 0.318 was reached, while in the second round overall kappa value improved to moderate (kappa?=?0.557; p?
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A novel method for genotyping the Helicobacter pylori vacA intermediate region directly in gastric biopsy specimens.
J. Clin. Microbiol.
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The present report describes a novel method for genotyping the virulence-associated vacA intermediate (i) region of Helicobacter pylori in archive material. vacA i-region genotypes as determined by the novel method were completely concordant with those of sequence analysis and with those of functional vacuolation activity. The method was further validated directly in gastric biopsy specimens of 386 H. pylori-positive cases, and effective characterization of the vacA i region was obtained in 191 of 192 (99.5%) frozen and in 186 of 194 (95.9%) formalin-fixed paraffin-embedded gastric biopsy specimens, respectively. The genotyping method was next used to address the relationship between the vacA genotypes and the cagA status. The vacA i1 genotype was associated with vacA s1 (where s indicates signal region), vacA m1 (where m indicates middle region), and cagA-positive genotypes (P < 0.0001), while the vacA i2 genotype was closely related with vacA s2, vacA m2, and cagA-negative genotypes (P < 0.0001). The relationship between H. pylori vacA i-region genotypes and gastric disease development was subsequently evaluated in the Portuguese population. Patients infected with vacA i1 strains showed an increased risk for gastric atrophy and for gastric carcinoma, with odds ratios of 8.0 (95% confidence interval [CI], 2.3 to 27) and of 22 (95% CI, 7.9 to 63), respectively. Taken together, the results show that this novel H. pylori vacA i-region genotyping method can be applied directly to archive material, providing a fast evaluation of strain virulence determinants without the need of culture. The results further emphasize that the characterization of the vacA i region may be useful to identify patients at higher risk of gastric carcinoma development.
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E-cadherin dysfunction in gastric cancer--cellular consequences, clinical applications and open questions.
FEBS Lett.
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E-cadherin plays a major role in cell-cell adhesion and inactivating germline mutations in its encoding gene predispose to hereditary diffuse gastric cancer. Evidence indicates that aside from its recognized role in early tumourigenesis, E-cadherin is also pivotal for tumour progression, including invasion and metastization. Herein, we discuss E-cadherin alterations found in a cancer context, associated cellular effects and signalling pathways, and we raise new key questions that will impact in the management of GC patients and families.
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Colorectal cancer and RASSF family--a special emphasis on RASSF1A.
Int. J. Cancer
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The RAS-association domain family, commonly referred to as RASSF, is a family of 10 members (RASSF1-10) implicated in a variety of key biological processes, including cell cycle regulation, apoptosis and microtubule stability. Furthermore, RASSFs have been implicated in tumorigenesis and several family members are now thought to be tumor suppressors. As opposed to the KRAS oncogene, for which mutational activation is frequent in colorectal cancer (CRC), RASSFs are found to be silenced mainly by aberrant promoter methylation. In particular, RASSF1A, RASSF2 and RASSF5 methylation has been associated with CRC development, though the mechanisms of action remain poorly understood. This review focus on the current knowledge of RASSF inactivation in CRC, particularly RASSF1A, and on the implications RASSFs may have as potential biomarkers and for the development of new targeted therapies for CRC.
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Epithelial E- and P-cadherins: role and clinical significance in cancer.
Biochim. Biophys. Acta
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E-cadherin and P-cadherin are major contributors to cell-cell adhesion in epithelial tissues, playing pivotal roles in important morphogenetic and differentiation processes during development, and in maintaining integrity and homeostasis in adult tissues. It is now generally accepted that alterations in these two molecules are observed during tumour progression of most carcinomas. Genetic or epigenetic alterations in E- and P-cadherin-encoding genes (CDH1 and CDH3, respectively), or alterations in their proteins expression, often result in tissue disorder, cellular de-differentiation, increased invasiveness of tumour cells and ultimately in metastasis. In this review, we will discuss the major properties of E- and P-cadherin molecules, its regulation in normal tissue, and their alterations and role in cancer, with a specific focus on gastric and breast cancer models.
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The number of Helicobacter pylori CagA EPIYA C tyrosine phosphorylation motifs influences the pattern of gastritis and the development of gastric carcinoma.
Histopathology
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To characterize the variation in virulence of Helicobacter pylori associated with CagA Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs, and to explore its relationship with the histopathological features of chronic gastritis and with the development of gastric carcinoma.
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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.