ABO blood serotype A is known to be associated with risk of gastric cancer (GC), but little is known how ABO alleles and the fucosyltransferase (FUT) enzymes and genes which are involved in Lewis antigen formation [and in Helicobacter pylori (H. pylori) binding and pathogenicity] may be related to GC risk in a European population. The authors conducted an investigation of 32 variants at ABO and FUT1-7 loci and GC risk in a case-control study of 365 cases and 1,284 controls nested within the EPIC cohort (the EPIC-Eurgast study). Four variants (including rs505922) in ABO, and allelic blood group A (AO+AA, odds ratio?=?1.84, 95%CI?=?1.20-2.80) were associated with diffuse-type GC; however, conditional models with other ABO variants indicated that the associations were largely due to allelic blood group A. One variant in FUT5 was also associated with diffuse-type GC, and four variants (and haplotypes) in FUT2 (Se), FUT3 (Le) and FUT6 with intestinal-type GC. Further, one variant in ABO, two in FUT3 and two in FUT6 were associated with H. pylori infection status in controls, and two of these (in FUT3 and FUT6) were weakly associated with intestinal-type GC risk. None of the individual variants surpassed a Bonferroni corrected p-value cutoff of 0.0016; however, after a gene-based permutation test, two loci [FUT3(Le)/FUT5/FUT6 and FUT2(Se)] were significantly associated with diffuse- and intestinal-type GC, respectively. Replication and functional studies are therefore recommended to clarify the role of ABO and FUT alleles in H. pylori infection and subtype-specific gastric carcinogenesis.
We performed a multistage genome-wide association study including 7,683 individuals with pancreatic cancer and 14,397 controls of European descent. Four new loci reached genome-wide significance: rs6971499 at 7q32.3 (LINC-PINT, per-allele odds ratio (OR) = 0.79, 95% confidence interval (CI) 0.74-0.84, P = 3.0 × 10(-12)), rs7190458 at 16q23.1 (BCAR1/CTRB1/CTRB2, OR = 1.46, 95% CI 1.30-1.65, P = 1.1 × 10(-10)), rs9581943 at 13q12.2 (PDX1, OR = 1.15, 95% CI 1.10-1.20, P = 2.4 × 10(-9)) and rs16986825 at 22q12.1 (ZNRF3, OR = 1.18, 95% CI 1.12-1.25, P = 1.2 × 10(-8)). We identified an independent signal in exon 2 of TERT at the established region 5p15.33 (rs2736098, OR = 0.80, 95% CI 0.76-0.85, P = 9.8 × 10(-14)). We also identified a locus at 8q24.21 (rs1561927, P = 1.3 × 10(-7)) that approached genome-wide significance located 455 kb telomeric of PVT1. Our study identified multiple new susceptibility alleles for pancreatic cancer that are worthy of follow-up studies.
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.
Thyroid cancer is the most common endocrine malignancy and nonmedullary thyroid carcinoma (NMTC) represents 90% of all cases. NMTC risk in first-degree relatives of affected cases is elevated fivefold to ninefold. Familial NMTC (FNMTC) accounts for about 3-7% of all thyroid tumors and is a more aggressive clinical entity than its sporadic counterparts. Linkage analysis on high-risk families performed a decade ago mapped several susceptibility loci, but did not lead to the identification of high-penetrance causal germline mutations. More recently, a genome-wide association study (GWAS) identified common single nucleotide polymorphisms (SNPs) affecting the risk of sporadic NMTC. We sought to verify if the newly identified genetic risk factors for NMTC are relevant for FNMTC as well. We genotyped 23 SNPs at 11 candidate loci in 672 subjects belonging to 133 pedigrees with at least two NMTC cases. Statistical analysis was performed using family-based association tests, modified quasi-likelihood score and logistic-normal models. SNPs at 9q22.33 near FOXE1 showed convincing evidence of association with NMTC risk in these high-risk families. The other tested loci resulted negative. These findings confirm the importance of the SNPs identified by recent GWAS on sporadic NMTC on FNMTC as well. However, the proposed FOXE1 causal variants do not show the strongest association signal. Moreover, mutation screening of the FOXE1 coding sequence in the FNMTC cases did not identify rarer causal variants, suggesting that other yet unidentified variants at this locus are involved in FNMTC etiology.
KRAS mutations are major factors involved in initiation and maintenance of pancreatic tumors. The impact of different mutations on patient survival has not been clearly defined. We screened tumors from 171 pancreatic cancer patients for mutations in KRAS and CDKN2A genes. Mutations in KRAS were detected in 134 tumors, with 131 in codon 12 and only 3 in codon 61. The GGT>GAT (G12D) was the most frequent mutation and was present in 60% (80/134). Deletions and mutations in CDKN2A were detected in 43 tumors. Analysis showed that KRAS mutations were associated with reduced patient survival in both malignant exocrine and ductal adenocarcinomas (PDAC). Patients with PDACs that had KRAS mutations showed a median survival of 17 months compared to 30 months for those without mutations (log-rank P?=?0.07) with a multivariate hazard ratio (HR) of 2.19 (95%CI 1.09-4.42). The patients with G12D mutation showed a median survival of 16 months (log-rank-test P?=?0.03) and an associated multivariate HR 2.42 (95%CI 1.14-2.67). Although, the association of survival in PDAC patients with CDKN2A aberrations in tumors was not statistically significant, the sub-group of patients with concomitant KRAS mutations and CDKN2A alterations in tumors were associated with a median survival of 13.5 months compared to 22 months without mutation (log-rank-test P?=?0.02) and a corresponding HR of 3.07 (95%CI 1.33-7.10). Our results are indicative of an association between mutational status and survival in PDAC patients, which if confirmed in subsequent studies can have potential clinical application.
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.
A higher incidence of stomach cancer in ABO blood type A individuals than in those with blood type O has been known for a long time. We studied this association in relation to Helicobacter pylori (Hp) of different cagA status. For our study, we used baseline gastric histopathology data and DNAs from frozen gastric biopsies of 2,077 subjects enrolled in a chemoprevention trial for gastric precancerous lesions in Venezuela. We analyzed six single nucleotide polymorphisms in the ABO gene, and we assessed the presence of the Hp cagA gene. Odds ratios (ORs) for risk of advanced precancerous gastric lesions were calculated using individuals with normal gastric epithelium or non-atrophic gastritis as a reference. Among individuals carrying a cagA negative Hp infection or no Hp infection, those with blood type A had a lower risk of intestinal metaplasia (IM) and dysplasia than those with blood type O (OR=0.60; 95% CI 0.38-0.94). In carriers of cagA positive Hp strains, individuals with blood type A had a higher risk of IM or dysplasia than those with blood type O (OR=1.42, 95% CI 1.09-1.86) and a higher risk if compared to subjects carrying cagA negative strain and non-A blood group (OR=3.82, 95% CI=2.80-5.20). The interaction between Hp cagA status and blood type was statistically significant (p=0.0006). We showed that SNPs in the ABO gene, predictive of ABO blood groups, are associated with risk of advanced precancerous gastric lesions in individuals infected with Hp, but the assessment of the risk is strictly dependent on cagA status.
There is strong epidemiologic evidence indicating that common genetic variability could be implicated in pancreatic cancer risk and, to date, various loci have been proposed. In particular, there is increasing evidence of the involvement of ABO gene variability and pancreatic cancer risk. In a large multicentric study of 1,028 pancreatic ductal adenocarcinoma cases and 2,257 controls in the context of the PANcreatic Disease ReseArch (PANDoRA) consortium, we investigated the suggested association with increased risk for carriers of single nucleotide polymorphisms (SNPs) determining the A or B allele in comparison with the O allele, which encodes for a non-functional enzyme. Since glycosyltransferase activity, encoded by ABO, is higher for the A1 variant compared with the A2 variant, we investigated the hypothesis that A1 carriers were at an increased risk of pancreatic cancer. In our analysis, carriers of the A1 were indeed at greater risk of developing the disease. In addition, we investigated the possible influence that genetic variability at the ABO locus may have in pancreatic cancer survival, but we observed no effect in our population.
SNPs in the Prostate Stem Cell Antigen (PSCA) gene have been found associated with gastric cancer (GC) risk in a genome-wide association study. This association has been replicated in several populations. In this study we assessed the impact of PSCA genotype on the risk of advanced gastric precancerous lesions and GC. We used baseline gastric histopathology data and DNA from frozen gastric biopsies of 2045 subjects enrolled in a chemoprevention trial for gastric precancerous lesions in Venezuela, and 180 cases of GC from the same area. We analyzed 3 SNPs in the PSCA gene (rs2294008, rs9297976 and rs12155758) which were previously found to be associated with GC risk in Europeans. The T allele of rs2294008 was found to be associated with a higher prevalence of atrophic gastritis (OR = 1.44; 95% CI 1.03-2.01 for the dominant model) and intestinal metaplasia (OR = 1.50; 95% CI 1.13-1.98 for the dominant model). We also confirmed the association with higher risk of gastric cancer (OR = 2.34; 95% CI 1.36-4.01 for the allele carriers). SNP rs12155758 was not associated with risk of gastric preneoplastic lesions, but we confirmed its association with higher GC risk (OR 1.95; 95% CI 1.29-2.97 for dominant model). We tested the relevance of the presence of the Helicobacter pylori cagA gene, which is known to increase the risk of more severe gastric lesions, but we did not find any clearcut interaction with PSCA SNPs in defining risk of gastric precancerous lesions or cancer.
Basal cell carcinoma (BCC) of the skin is the most common neoplasm among the Caucasian population of the Western world. Inflammation may result in oxidative stress and contribute to promotion and progression of tumors, including BCC. The role of cytokines, which are inflammatory modulators, in the biology of tumors has been extensively studied and it is well known that they are aberrantly produced by cancer cells, macrophages and other phagocytic cells. Genetic polymorphisms are known in several cytokine genes, which result in altered expression. In the present association study, we investigated the association of 14 functional polymorphisms in 11 cytokines genes with BCC risk in 529 BCC cases and 532 healthy controls. We have also tested the possible interactions between the genetic variants and three known risk factors for BCC: skin complexion, sun effect and skin response to sun exposure. We did not observe any statistically significant association between SNPs and BCC risk. However, we found that, in a subgroup of subjects more prone to skin burns, carriers of at least one copy of the G allele of rs1800629 (TNF) had an increased risk of BCC [odds ratio (OR) = 2.40, 95% confidence interval (CI) 1.38-4.16, P = 0.0005]. Moreover, in subjects less prone to sunburns, we observed that carriers of the C allele of rs1143627 (IL1B) showed a decreased risk (OR = 0.53, 95% CI 0.34-0.82, P = 0.0019). In conclusion, we found that two polymorphisms in inflammatory genes interacting with environmental risk factors could modulate BCC risk.
Pancreatic cancer has one of the worst mortality rates of all cancers. Little is known about its etiology, particularly regarding inherited risk. The PanScan project, a genome-wide association study, identified several common polymorphisms affecting pancreatic cancer susceptibility. Single nucleotide polymorphisms (SNPs) in ABO, sonic hedgehog (SHH), telomerase reverse transcriptase (TERT), nuclear receptor subfamily 5, group A, member 2 (NR5A2) were found to be associated with pancreatic cancer risk. Moreover the scan identified loci on chromosomes 13q22.1 and 15q14, to which no known genes or other functional elements are mapped. We sought to replicate these observations in two additional, independent populations (from Germany and the UK), and also evaluate the possible impact of these SNPs on patient survival. We genotyped 15 SNPs in 690 cases of pancreatic ductal adenocarcinoma (PDAC) and in 1277 healthy controls. We replicated several associations between SNPs and PDAC risk. Furthermore we found that SNP rs8028529 was weakly associated with a better overall survival (OS) in both populations. We have also found that NR5A2 rs12029406_T allele was associated with a shorter survival in the German population. In conclusion, we found that rs8028529 could be, if these results are replicated, a promising marker for both risk and prognosis for this lethal disease.
Basal cell carcinoma (BCC) of the skin is the most common neoplasm among the Caucasian population of the western world. Ultraviolet (UV) radiation-induced p53 activation promotes cutaneous pigmentation by increasing transcriptional activity of pro-opiomelanocortin (POMC) in the skin. Induction of POMC/?-melanocyte-stimulating hormone (?-MSH) activates the melanocortin 1 receptor (MC1R), resulting in skin pigmentation. The tumor suppressor p53 is a key player in stress responses that preserve genomic stability, responding to a variety of insults including DNA damage, hypoxia, metabolic stress and oncogene activation. Malfunction of the p53 pathway is an almost universal hallmark of human tumors. Polymorphisms in the gene encoding p53 (TP53) alter its transcriptional activity, which in turn may influence the UV radiation-induced tanning response.
The 22q11.2 region is a hotspot for chromosomal rearrangements mediated by LCR22A-D low-copy repeats. Sequence motifs and homology-driven mechanisms have been suggested to mediate rearrangements. Nevertheless, recent evidence has emphasized the role of functional properties in genome instability, suggesting that replication timing transition regions could be peculiarly prone to genetic damage. In this work, we show that an early-late replication-transition zone is localised within LCR22A, the shared proximal endpoint of the majority of deletions and duplications of 22q11.2 region. Transition zone is characterized by asynchronous replication and by a DNA flexibility peak, features which are relevant for double-strand breaks and rearrangements at fragile sites. This and other flexibility peaks, associated with less relevant replication anomalies, are present in clusters inside LCR22A, B and D. All of them are composed of modules of AT-rich sequences, DNA satellites, and a HIV-1 integration site; moreover, they have coincidental position with boundaries of duplicons inside segmental duplications and with breakpoints of recurrent translocations. Noteworthy, flexibility peaks also lay at breakpoints of translocation partner chromosomes, three of which, 1p21.2, 8q24.13 and 11q23.3, have been positioned inside known common fragile sites. In many cases peaks are associated with potential matrix attachment regions (MARs). We propose that, similarly to fragile sites, replication perturbation and flexibility peaks may mediate strand breakage and rearrangements. Consistently with this view we show that the replication timing transition zone detected inside LCR22A is susceptible to replicative stress by aphidicolin, known inducer of fragile sites. These findings emphasize the significance of mutagenic exposure for the constitutional syndrome origin.
Two recent genome-wide association studies (GWAS) of pancreatic ductal adenocarcinoma (PDAC), conducted, respectively, in a Japanese and in a Chinese population, identified eight novel loci affecting PDAC risk.
Pancreatic cancer is the fourth leading cause of cancer deaths in the European Union and in the USA, but little is known about its genetic susceptibility. The PANcreatic Disease ReseArch (PANDoRA) consortium was established to unite the efforts of different research groups; its aim is to create a large bio-database to uncover new genetic factors for pancreatic cancer risk, response to treatment, and patient survival. So far 2220 cases of pancreatic adenocarcinoma, a smaller number of cases of endocrine pancreatic tumours (n=86), chronic pancreatitis (n=272) and 3847 healthy controls have been collected. As a collective effort of the consortium, SNPs associated with pancreatic adenocarcinoma risk from a genome-wide association study performed in Caucasians were replicated. The possibility that the same genetic polymorphisms may influence patient survival as well was also addressed. This collective effort is particularly important for pancreatic cancer because it is a relatively rare disease for which little is known about aetiopathogenesis and risk factors. The recruitment of additional collaborators and partner institutions is continuously on-going.
Several studies have shown that genetic factors account for 25% of the variation in human life span. On the basis of published molecular, genetic and epidemiological data, we hypothesized that genetic polymorphisms of taste receptors, which modulate food preferences but are also expressed in a number of organs and regulate food absorption processing and metabolism, could modulate the aging process. Using a tagging approach, we investigated the possible associations between longevity and the common genetic variation at the three bitter taste receptor gene clusters on chromosomes 5, 7 and 12 in a population of 941 individuals ranging in age from 20 to 106 years from the South of Italy. We found that one polymorphism, rs978739, situated 212 bp upstream of the TAS2R16 gene, shows a statistically significant association (p?=?0.001) with longevity. In particular, the frequency of A/A homozygotes increases gradually from 35% in subjects aged 20 to 70 up to 55% in centenarians. These data provide suggestive evidence on the possible correlation between human longevity and taste genetics.
The pathways that regulate energy homeostasis, the mechanisms of damage repair, and the signaling response to internal environmental changes or external signals have been shown to be critical in modulating lifespan of model organisms and humans. In order to investigate whether genetic variation of genes involved in these pathways contribute to longevity, a two-stage case-control study in two independent sets of long-lived individuals from Calabria (Italy) was performed. In stage 1, 317 SNPs in 104 genes were analyzed in 78 cases (median age 98 years) and 71 controls (median age 67 years). In stage 2, 31 candidate SNPs identified in stage 1 (? markers = 0.1) were analyzed in an independent sample composed by 288 cases (median age 92 years) and 554 controls (median age 67 years). Two SNPs, rs282070 located in intron 1 of the MAP3K7 gene, and rs2111699 located in intron 1 of the GSTZ1 gene, were significantly associated (after adjustment for multiple testing) with longevity in stage 2 (p?=?1.1?×?10(-3) and p?=?1.4?×?10(-3), respectively). Interestingly, both genes are implicated in the cellular response to internal and external environmental changes, playing a crucial role in the inflammation processes that accompany aging. Our data confirm that long-lived subjects are endowed with genetic variants that allow them to optimize these cellular responses and to better deal with environmental and internal stresses.
Helicobacter pylori (HP) is a bacterium that colonizes the human stomach and can establish a long-term infection of the gastric mucosa. Persistent Hp infection often induces gastritis and is associated with the development of peptic ulcer disease, atrophic gastritis, and gastric adenocarcinoma. Virulent HP isolates harbor the cag (cytotoxin-associated genes) pathogenicity island (cagPAI), a 40 kb stretch of DNA that encodes components of a type IV secretion system (T4SS). This T4SS forms a pilus for the injection of virulence factors into host target cells, such as the CagA oncoprotein. We analyzed the genetic variability in cagA and other selected genes of the HP cagPAI (cagC, cagE, cagL, cagT, cagV and cag Gamma) using DNA extracted from frozen gastric biopsies or from clinical isolates. Study subjects were 95 cagA+ patients that were histologically diagnosed with chronic gastritis or gastric cancer in Venezuela and Mexico, areas with high prevalence of Hp infection. Sequencing reactions were carried out by both Sanger and next-generation pyrosequencing (454 Roche) methods. We found a total of 381 variants with unambiguous calls observed in at least 10% of the originally tested samples and reference strains. We compared the frequencies of these genetic variants between gastric cancer and chronic gastritis cases. Twenty-six SNPs (11 non-synonymous and 14 synonymous) showed statistically significant differences (P<0.05), and two SNPs, in position 1039 and 1041 of cagE, showed a highly significant association with cancer (p-value?=?2.07×10??), and the variant codon was located in the VirB3 homology domain of Agrobacterium. The results of this study may provide preliminary information to target antibiotic treatment to high-risk individuals, if effects of these variants are confirmed in further investigations.
Related JoVE Video
Journal of Visualized Experiments
What is Visualize?
JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.
How does it work?
We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.
Video X seems to be unrelated to Abstract Y...
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.