Syndecan-1 (SDC1/CD138) is one of the main cell surface proteoglycans and is involved in crucial biological processes. Only a few studies have analyzed the role of SDC1 in mesenchymal tumor pathogenesis. In particular, its involvement in adipose tissue tumors has never been investigated. Dedifferentiated liposarcoma, one of the most frequent types of malignant adipose tumors, has a high potential of recurrence and metastastic evolution. Classical chemotherapy is inefficient in metastatic dedifferentiated liposarcoma and novel biological markers are needed for improving its treatment. In this study, we have analyzed the expression of SDC1 in well-differentiated/dedifferentiated liposarcomas and showed that SDC1 is highly overexpressed in dedifferentiated liposarcoma compared to normal adipose tissue and lipomas. Silencing of SDC1 in liposarcoma cells impaired cell viability and proliferation. Using the human multipotent adipose-derived stem (hMADS) cell model of human adipogenesis, we showed that SDC1 promotes proliferation of undifferentiated adipocyte progenitors and inhibits their adipogenic differentiation. Altogether, our results support the hypothesis that SDC1 might be involved in liposarcomagenesis. It might play a prominent role in the dedifferentiation process occurring when well-differentiated liposarcoma progress to dedifferentiated liposarcoma. Targeting SDC1 in these tumors might provide a novel therapeutic strategy.
Cytogenetically, most dermatofibrosarcoma protuberans are characterized by chromosomal rearrangements resulting in the collagen type-1 alpha 1 (COL1A1)-platelet-derived growth factor ? (PDGFB) fusion gene. This abnormality can be detected by fluorescence in situ hybridization (FISH) analysis in routine practice. The aim of this study was to evaluate the role of the FISH analysis in the diagnosis of dermatofibrosarcoma protuberans. A FISH analysis was prospectively and systematically performed on a series of 448 consecutive tumor specimens. All cases were reviewed by two independent pathologists and classified in three categories according to the probability of a DFSP diagnosis before molecular analyses. Cases were classified as certain when dermatofibrosarcoma protuberans was the only possible diagnosis. Those cases for which dermatofibrosarcoma protuberans remained the first diagnosis, but other differential diagnosis existed, were regarded as probable. When dermatofibrosarcoma protuberans was considered a differential diagnosis, they were labeled as possible. The final diagnosis was supported by clinicopathological findings and results of FISH analyses. Immunohistochemical analysis of CD34 was systematically performed, and additional markers when necessary. The cases (n=37) with a non-interpretable FISH were excluded. For the 185 certain tumors specimens: 178 (96%) FISH analyses showed a PDGFB/COL1A1 rearrangement, 7 (4%) were negative. For the 114 probable tumors specimens: 104 (91%) FISH analyses were positive and 10 (9%) were negative leading to a new diagnosis in 8 cases. For the 112 possible cases: 91 (81%) FISH analyses were negative and 21 (19%) were positive. Of the 21 cases, initial diagnoses included unclassified sarcoma, myxofibrosarcoma, dermatofibroma, reactive lesion, solitary fibrous tumor, perineurioma, benign nerve sheath tumor, and undifferentiated spindle cell tumor without malignant evidence. FISH analysis has been helpful for confirming the diagnosis of dermatofibrosarcoma protuberans in 25% (104/411) of cases and necessary for the diagnosis of dermatofibrosarcoma protuberans in 5% (21/411) of cases.Modern Pathology advance online publication, 1 August 2014; doi:10.1038/modpathol.2014.97.
Despite the numerous available drugs, the most appropriate treatments for patients affected by common or rare renal cell carcinomas (RCC), like those associated with the Xp11.2 translocation/transcription factor for immunoglobulin heavy-chain enhancer 3 (TFE3) gene fusion (TFE3 RCC), are not clearly defined. We aimed to make a parallel between the sensitivity to targeted therapies on living patients and on cells derived from the initial tumor. Three patients diagnosed with a metastatic RCC (one clear cell RCC [ccRCC], two TFE3 RCC) were treated with anti-angiogenesis drugs. The concentrations of the different drugs giving 50% inhibition of cell proliferation (IC50) were determined with the Thiazolyl Blue Tetrazolium Bromide (MTT) assay on cells from the primary tumors and a reference sensitive RCC cell line (786-O). We considered the cells to be sensitive if the IC50 was lower or equal to that in 786-O cells, and insensitive if the IC50 was higher to that in 786-O cells (IC 50 of 6 ± 1 µM for sunitinib, 10 ± 1 µM for everolimus and 6 ± 1 µM for sorafenib). Based on this standard, the response in patients and in cells was equivalent. The efficacy of anti-angiogenesis therapies was also tested in cells obtained from five patients with non-metastatic ccRCC, and untreated as recommended by clinical practice in order to determine the best treatment in case of progression toward a metastatic grade. In vitro experiments may represent a method for evaluating the best first-line treatment for personalized management of ccRCC during the period following surgery.
Sarcomas represent a complex and heterogeneous group of rare malignant tumors and their correct diagnosis is often difficult. Recent molecular biological techniques have been of great diagnostic use and there is a need to assess the cost of these procedures in routine clinical practice. Using prospective and observational data from eight molecular biology laboratories in France, we used "microcosting" method to assess the cost of molecular biological techniques in the diagnosis of five types of sarcoma. The mean cost of fluorescence in situ hybridization (FISH) was 318 € (273-393) per sample; mean reverse transcription polymerase chain reaction (RT-PCR) cost ranged from 300 € (229-481) per formalin-fixed, paraffin-embedded specimen to 258 € (213-339) per frozen specimen; mean quantitative polymerase chain reaction (Q-PCR) cost was 184 € (112-229) and mean CGH-array cost was 332 € (329-335). The cost of these recently implemented techniques varied according to the type of sarcoma; the method of tissue collection and local organizational factors including the level of local expertise and investment. The cost of molecular diagnostic techniques needs to be balanced against their respective performance.
Degradation of signaling proteins is one of the most powerful tumor-suppressive mechanisms by which a cell can control its own growth. Here, we identify RHOA as the molecular target by which autophagy maintains genomic stability. Specifically, inhibition of autophagosome degradation by the loss of the v-ATPase a3 (TCIRG1) subunit is sufficient to induce aneuploidy. Underlying this phenotype, active RHOA is sequestered via p62 (SQSTM1) within autolysosomes and fails to localize to the plasma membrane or to the spindle midbody. Conversely, inhibition of autophagosome formation by ATG5 shRNA dramatically increases localization of active RHOA at the midbody, followed by diffusion to the flanking zones. As a result, all of the approaches we examined that compromise autophagy (irrespective of the defect: autophagosome formation, sequestration, or degradation) drive cytokinesis failure, multinucleation, and aneuploidy, processes that directly have an impact upon cancer progression. Consistently, we report a positive correlation between autophagy defects and the higher expression of RHOA in human lung carcinoma. We therefore propose that autophagy may act, in part, as a safeguard mechanism that degrades and thereby maintains the appropriate level of active RHOA at the midbody for faithful completion of cytokinesis and genome inheritance.
Primitive neuroectodermal tumors (PNET) represent 1% of sarcomas. Head and neck peripheral PNETs have an intermediate prognosis between abdominopelvic disease and extremities. We here report the case of a 40-year old male who presented with primitive neuroectodermal tumor of the thyroid and was treated by multimodal treatment, including surgery, chemotherapy and intermediate dose radiotherapy. The patient is alive and fit with a functional larynx at 27 months. Multimodal treatments yield five-year survival rates of about 60%. Major drug regimens use vincristine, doxorubicin, ifosfamide or cyclophosphamide, dactinomycin and/or etoposide. Complete surgical excision is undertaken whenever possible to improve long-term survival. However, the relative radiosensitivity of tumors of the Ewing family, suggest multimodal treatment including adjuvant conformal radiotherapy in case of positive margins or poor response to chemotherapy rather than resection with 2-3 cm margins, which would imply laryngeal sacrifice for thyroid tumors. The role of expert rare tumor networks is crucial for optimal decision-making and management of such rare tumors on a case by case basis.
The aim of this study was to determine the frequency of EGFR, KRAS, BRAF, and HER-2 mutations in brain metastases from non-small cell lung carcinomas (BM-NSCLC). A total of 77 samples of BM-NSCLC were included and 19 samples of BM from breast, kidney, and colorectal tumors were also studied as controls. These samples were collected from patients followed between 2008 and 2011 at Poitiers and Nice University Hospitals in France. The frequencies of EGFR, KRAS, BRAF, and HER-2 mutations in BM-NSCLC were 2.6, 38.5, 0, and 0% respectively. The incidence of KRAS mutation was significantly higher in female and younger patients (P < 0.05). No mutations of the four genes were found in BM from breast or kidney. However, among six BM from colorectal tumors, we identified KRAS mutations in three cases and BRAF mutations in two other cases. This study is the largest analysis on genetic alterations in BM-NSCLC performed to date. Our results suggest a low frequency of EGFR mutations in BM-NSCLC whereas KRAS mutations are as frequent in BM-NSCLC as in primitive NSCLC. These results raise the question of the variability of the brain metastatic potential of NSCLC cells in relation to the mutation pattern.
Most lipomas are characterized by translocations involving the HMGA2 gene in 12q14.3. These rearrangements lead to the fusion of HMGA2 with an ectopic sequence from the translocation chromosome partner. Only five fusion partners of HMGA2 have been identified in lipomas so far. The identification of novel fusion partners of HMGA2 is important not only for diagnosis in soft tissue tumors but also because these genes might have an oncogenic role in other tumors. We observed that t(1;12)(p32;q14) was the second most frequent translocation in our series of lipomas after t(3;12)(q28;q14.3). We detected overexpression of HMGA2 mRNA and protein in all t(1;12)(p32;q14) lipomas. We used a fluorescence in situ hybridization-based positional cloning strategy to characterize the 1p32 breakpoint. In 11 cases, we identified PPAP2B, a member of the lipid phosphate phosphatases family as the 1p32 target gene. Reverse transcription-polymerase chain reaction analysis followed by nucleotide sequencing of the fusion transcript indicated that HMGA2 3 untranslated region (3UTR) fused with exon 6 of PPAP2B in one case. In other t(1;12) cases, the breakpoint was extragenic, located in the 3region flanking PPAP2B 3UTR. Moreover, in one case showing a t(1;6)(p32;p21) we observed a rearrangement of PPAP2B and HMGA1, which suggests that HMGA1 might also be a fusion partner for PPAP2B. Our results also revealed that adipocytic differentiation of human mesenchymal stem cells derived from adipose tissue was associated with a significant decrease in PPAP2B mRNA expression suggesting that PPAP2B might play a role in adipogenesis.
Dermatofibrosarcoma Protuberans (DFSP) carries a translocation resulting in the COL1A1/PDGFB fusion-gene, responsible for platelet derived growth factor beta receptor (PDGFRB) activation. Fibrosarcomatous (FS) transformation in DFSP rarely occur. The fusion-gene and PDGFRB expression/activation pattern and imatinib role in DFSP-derived FS is less defined. We reviewed all consecutive patients operated for localized DFSP at our institution from 1994 to 2009, selecting cases with FS component. We also reviewed patients treated with imatinib for advanced FS-DFSP over the same period. When cryopreserved material was available, biochemical/molecular analyses were performed. Of 275 DFSPs, 13 (4.7%) showed a FS component. Fifteen percent of these patients developed metastases, one to the brain. Four patients with DFSP-derived FS received imatinib, with a Response Evaluation Criteria in Solid Tumor Partial Response. Response was followed by early secondary progression in two. One died for brain metastases. Three patients underwent surgery after imatinib. The fusion-gene was detected in all cases in both the classical and FS component, before and after imatinib. PDGFRB expression/activation was confirmed in all cases. mTOR was switched-off, despite the phosphorylation of its effectors. However, a strong phosphorylation of S6 and 4EBP1 was restricted to the FS component. In conclusion, DFSP-derived FS maintains the fusion-gene, being sensitive to imatinib. However, responses are short-lasting. Secondary resistance to imatinib is not related to PDGFRB.
Low-grade osteosarcoma is a rare malignancy that may be subdivided into two main subgroups on the basis of location in relation to the bone cortex, that is, parosteal osteosarcoma and low-grade central osteosarcoma. Their histological appearance is quite similar and characterized by spindle cell stroma with low-to-moderate cellularity and well-differentiated anastomosing bone trabeculae. Low-grade osteosarcomas have a simple genetic profile with supernumerary ring chromosomes comprising amplification of chromosome 12q13-15, including the cyclin-dependent kinase 4 (CDK4) and murine double-minute type 2 (MDM2) gene region. Low-grade osteosarcoma can be confused with fibrous and fibro-osseous lesions such as fibromatosis and fibrous dysplasia on radiological and histological findings. We investigated MDM2-CDK4 immunohistochemical expression in a series of 72 low-grade osteosarcomas and 107 fibrous or fibro-osseous lesions of the bone or paraosseous soft tissue. The MDM2-CDK4 amplification status of low-grade osteosarcoma was also evaluated by comparative genomic hybridization array in 18 cases, and the MDM2 amplification status was evaluated by fluorescence in situ hybridization or quantitative real-time polymerase chain reaction in 31 cases of benign fibrous and fibro-osseous lesions. MDM2-CDK4 immunostaining and MDM2 amplification by fluorescence in situ hybridization or quantitative real-time polymerase chain reaction were investigated in a control group of 23 cases of primary high-grade bone sarcoma, including 20 conventional high-grade osteosarcomas, two pleomorphic spindle cell sarcomas/malignant fibrous histiocytomas and one leiomyosarcoma. The results showed that MDM2 and/or CDK4 immunoreactivity was present in 89% of low-grade osteosarcoma specimens. All benign fibrous and fibro-osseous lesions and the tumors of the control group were negative for MDM2 and CDK4. These results were consistent with the MDM2 and CDK4 amplification results. In conclusion, immunohistochemical expression of MDM2 and CDK4 is specific and provides sensitive markers for the diagnosis of low-grade osteosarcomas, helping to differentiate them from benign fibrous and fibro-osseous lesions, particularly in cases with atypical radio-clinical presentation and/or limited biopsy samples.
The aim of our study was first to assess the role of HMGA2 expression in the pathogenesis of adipocytic tumors (AT) and, second, to seek a potential correlation between overexpression of HMGA2 and let-7 expression inhibition by analyzing a series of 56 benign and malignant AT with molecular cytogenetic data. We measured the levels of expression of HMGA2 mRNA and of eight members of the let-7 microRNA family using quantitative RT-PCR and expression of HMGA2 protein using immunohistochemistry. HMGA2 was highly overexpressed in 100% of well-differentiated/dedifferentiated liposarcomas (WDLPS/DDLPS), all with HMGA2 amplification, and 100% of lipomas with HMGA2 rearrangement. Overexpression of HMGA2 mRNA was detected in 76% of lipomas without HMGA2 rearrangement. HMGA2 protein expression was detected in 100% of lipomas with HMGA2 rearrangement and 48% of lipomas without HMGA2 rearrangement. We detected decreased expression levels of some let-7 members in a significant proportion of AT. Notably, let-7b and let-7g were inhibited in 61% of WDLPS/DDLPS. In lipomas, each type of let-7 was inhibited in approximately one-third of the cases. Although overexpression of both HMGA2 mRNA and protein in a majority of ordinary lipomas without HMGA2 structural rearrangement may have suggested a potential role for let-7 microRNAs, we did not observe a significant link with let-7 inhibition in such cases. Our results indicate that inhibition of let-7 microRNA expression may participate in the deregulation of HMGA2 in AT but that this inhibition is neither a prominent stimulator for HMGA2 overexpression nor a surrogate to genomic HMGA2 rearrangements.
A child with plexiform fibrohistiocytic tumor is presented, in whom a superficial biopsy was misdiagnosed as an inflammatory granuloma. Cytogenetic analysis revealed a 46,X,del(X)(q13)/46,XX karyotype. However, fluorescence in situ hybridization (FISH) and array-comparative genomic hybridization (CGH) analysis failed to detect any numerical or quantitative genomic anomaly. Because of lack of specific chromosomal hallmarks, a molecular diagnosis of plexiform fibrohistiocytic tumor with the currently available tools is not reliable.
The treatment of dermatofibrosarcoma protuberans (DFSP) involves wide local excision with frequent need for reconstructive surgery. A t(17;22) translocation resulting in COL1A1-PDGFB fusion is present in >95% of cases. Certain patient observations and a report on nine patients suggest that imatinib mesylate, targeting platelet-derived growth factor receptor beta, has clinical potential in DFSP. The primary aim of this phase II multicenter study was to define the percentage of clinical responders (Response Evaluation Criteria in Solid Tumors) to a 2-month preoperative daily administration of 600 mg of imatinib mesylate before wide local excision. The secondary aims were to determine tolerance, objective response from imaging results (ultrasound and magnetic resonance imaging), and pathologic responses observed in sequential tissue specimens.
Histological features are usually sufficient for providing an accurate diagnosis of renal cell carcinomas (RCC). However, the morphological appearance might sometimes be misleading. For instance, RCC with papillary areas and extensive clear cell changes may be difficult to classify either as clear cell renal carcinoma or as papillary renal cell carcinoma (pRCC). We used the combination of immunohistochemistry, conventional cytogenetics, fluorescence in situ hybridization (FISH), bacterial artificial chromosomes comparative genomic hybridization arrays and high-density single nucleotides polymorphism arrays (SNP arrays) to characterize three cases of RCC showing a predominant cytology of cells with clear cytoplasm and variable amounts of papillary areas. In accordance with the 2004 World Health Organization (WHO) classification, we initially assessed the diagnosis of clear cell RCC for one of the cases and unclassified RCC for the two remaining cases. However, because of a strong immunohistochemical labeling for alpha-methylacyl-CoA racemase, as well as the presence of a gain of chromosomes 7 and 17, we concluded that two of these tumors were actually pRCC. As for the third case, because of the presence of both pCCR and ccCCR molecular cytogenetic aberrations, including gains of chromosomes 7 and 17, loss of chromosome Y and whole chromosome 3 loss of heterozyosity (isodisomy), the final diagnosis was hybrid tumor cc-pRCC, so-called "unclassified RCC" according to the WHO classification. Our observations demonstrate the necessity to use immunohistochemical and cytogenetic tools in all cases of RCC showing unusual features. The combination of FISH and SNP arrays is prevailing for characterizing cases with hybrid features.
Renal cell carcinoma (RCC) with translocation involving Xp11.2 (Xp11.2-RCC) is a rare neoplasm that usually occurs in children and young adults. This incidence is underestimated in adults because its morphological similarities with clear-cell RCC or papillary RCC2,3, as well as immunohistochemical and cytogenetic analyses are not carried out systematically in adults. We present a novel case of Xp11.2-RCC in a 57-year-old woman. The histologic features were those of a clear-cell RCC. Molecular cytogenetic analysis showed an uncommon t(X;1)(p11.2;p34) with TFE3 rearrangement and no alteration of chromosome 3. The immunohistochemical analysis showed expression of the TFE3 protein. Only nine cases of (X;1)(p11.2;p34) have been published, most of them occurring in children or young adults. To our knowledge, this is the second report of such a translocation in a patient older than 55 years. After a follow-up period of 13 months, the patient showed no evidence of disease. The clinical outcome was favorable, indicating that this particular translocation might be associated with a good prognosis. This observation confirms that Xp11.2-RCC are very likely to be underestimated in adults older than 40 years, and it highlights the importance of performing immunohistochemical and cytogenetic analyses in RCC for accurate diagnosis.
KRAS and BRAF mutations in primary colorectal tumors (PT) are predictive of nonresponse to anti-epidermal growth factor receptor (EGFR) antibodies in patients with metastatic colorectal cancer (mCRC). The question of primary resistance to anti-EGFR treatment as a result of the presence of KRAS or BRAF mutations only in metastases has been raised but not resolved.
The MDM2 and HMGA2 genes are consistently amplified in well-differentiated/dedifferentiated liposarcomas (WDLPS/DDLPS) whereas CDK4 is frequently but not always amplified in these tumors. Our goal was to determine whether the absence of CDK4 amplification was (a) correlated to a specific clinico-histopathologic profile; and (b) compensated by another genomic anomaly involving the CCND1/CDK4/P16INK4a/RB1/E2F pathway.
Sarcomatoid carcinomas (SC) of the lung are uncommon malignant tumors composed of carcinomatous and sarcomatous cell components and characterized by a more aggressive outcome than other histological subtypes of nonsmall cell lung cancer (NSCLC). Although epidermal growth factor receptor (EGFR)-targeted therapies have emerged as a promising therapeutic approach in patients with advanced typical NSCLC such as adenocarcinoma, the potential clinical activity of these drugs in lung SC is still unknown. To investigate this point, we have analyzed the status of 4 EGFR pathways biomarkers in a series of lung SC. EGFR protein expression, EGFR gene copy number, EGFR mutational status and KRAS mutational status were assessed in a series of 22 consecutive cases of primary lung SC. EGFR protein overexpression was observed in all the cases. High level of polysomy (>or=4 copies of the gene in >40% of cells) was detected in 5 cases (23%). No EGFR mutation was detected. KRAS mutations were found in 8 patients (38%; Gly12Cys in 6 cases and Gly12Val in 2 cases). The consistent EGFR protein overexpression and the high rate of KRAS mutation may contribute to the poorer outcome of lung SC in comparison with typical NSCLC. The rare incidence of increased EGFR gene copy number, the lack of EGFR mutation and the high rate of KRAS mutation observed in our series also suggest that most patients with lung SC are not likely to benefit from anti-EGFR therapies.
Despite complex genetics, aneuploid tumors like dedifferentiated liposarcoma have specific and reproducible chromosomal changes such as amplification of HDM2 and CDK4 that represent potential targets for systemic therapy. In addition, there are cancer cell survival pathways that may not be the target of chromosomal translocations or mutations that are still estimable targets for new systemic therapeutics, be it pathways involved in angiogenesis or apoptosis. In this review, we examine target selection for specific sarcoma subtypes, and demonstrate with a few examples new techniques being used to delineate novel therapeutic inroads for patients with sarcoma.
Well-differentiated and undifferentiated liposarcomas are characterized by high-level amplifications of chromosome 12 regions including the CDK4 and MDM2 genes. These amplicons are either localized, in well-differentiated liposarcoma (WDLPS), on extrachromosomal structures (ring or rod chromosomes), or integrated into chromosome arms in undifferentiated tumors. Our results reveal that extrachromosomal amplicons are unstable, and frequently lost by micronucleation. This loss correlates with hypermethylation of eliminated sequences and changes of their replication time. Treatment of cells with demethylating agents during early S-phase significantly decreases the rate of micronuclei positive for CDK4. We also demonstrate that, in our model, micronuclei are generated during anaphase as a consequence of anaphase abnormalities (chromosome lagging and anaphase bridges). Finally, a dramatic increase of adipocytic differentiation was noted in cells that have eliminated copies of CDK4 gene in micronuclei. These findings provide evidence that, in WDLPS, adipocytic differentiation could be the consequence of CDK4 loss, an event occurring rarely in undifferentiated tumors in which the amplified sequences are integrated into chromosome arms.
Lipomas are frequently characterized by aberrations of the 12q13 approximately q15 chromosomal region and often by rearrangements of the HMGA2 gene. These rearrangements include the formation of chimeric genes that fuse the 5 region of HMGA2 with a variety of partners, such as LPP (3q28) or NFIB (9p22). We describe here the fourth reported case of lipoma showing a HMGA2-NFIB fusion, and the first one in a child. We found a translocation t(9;12)(p22;q14) in a deep-seated intramuscular lipoma occurring in the buttock of a 5-year-old boy. By fluorescence in situ hybridization and reverse-transcription polymerase chain reaction, we have shown that the translocation t(9;12) resulted in an in-frame fusion of the first four exons of HMGA2 with the last exon of NFIB. Intramuscular lipomas are very rare in childhood. Our results confirm that lipomas containing NFIB rearrangements may be related to peculiar clinicohistologic features, including large size, deep situation, infiltration of surrounding muscles, or precocious occurrence. Both the truncation of HMGA2 and the nature of its fusion partner gene might be relevant in the adipose tissue tumorigenesis.
We report the clinical and pathologic features of, what is to the best of our knowledge, the first case of epithelioid sarcoma of bone. A 31-year-old woman with an unremarkable past medical history presented with pelvic pain and was found by computed tomography scan to have a destructive 5 cm, partially calcified intraosseous lesion of the iliac bone. Histologically, the tumor consisted of relatively uniform but clearly malignant-appearing epithelioid cells, with scattered rhabdoid-appearing cells. A hyalinized to partially calcified matrix was present between the tumor cells, with a "chickenwire" pattern of calcification. By immunohistochemistry, the neoplastic cells expressed cytokeratins, vimentin, epithelial membrane antigen and CD34, and showed complete loss of INI1 protein expression. Fluorescence in situ hybridization showed homozygous deletion of the INI1 gene. An extensive clinical and radiographic workup did not show evidence of a soft tissue tumor, and the diagnosis of a primary epithelioid sarcoma of bone was made. After this, the patient underwent a complete resection of her tumor, and is currently disease free, 6 months after surgery. These extremely rare tumors must be rigorously distinguished from other more common tumors of bone, in particular, chondroblastoma and osteosarcoma. Awareness that epithelioid sarcoma may occur in bone, careful histologic evaluation and ancillary immunohistochemistry for epithelial markers, CD34 and INI1 protein should allow for recognition of such tumors. Study of additional cases of primary epithelioid sarcoma of bone will be necessary to better understand its clinical behavior.
Atypical lipomatous tumor or well-differentiated liposarcoma (ALT-WDLPS) and dedifferentiated liposarcoma (DDLPS) share the same basic genetic abnormality characterized by a simple genomic profile with a 12q14-15 amplification involving MDM2 gene. These tumors are the most frequent LPS. This paper reviews the molecular pathology, general clinical and imaging features, histopathology, new diagnostic tools, and prognosis of ALT-WDLPS and DDLPS.
Salivary gland oncocytic lipoadenoma is an exceptional benign tumor composed of mature adipose tissue associated with a mixture of oncocytes. We report a case of oncocytic lipoadenoma showing sebaceous differentiation, and provide a cytogenetic analysis, which has not yet been described. A 64-year-old male developed a left parotid gland, well-encapsulated tumor measuring 3.5 x 3 cm(2), showing mature fat cells associated with oncocytic changes of epithelial components. Immunohistochemistry showed a dual epithelial population with ductal (positivity for AE1/AE3, CK19, CK7 antibodies) and basal-cell (positivity for p63, CK14, CK5,6 antibodies) differentiation in oncocytic areas. Moreover, oncocytic cells were stained with anti-alpha-1 antichymotrypsin antibody and phosphotungstic acid-hematoxylin staining. Molecular cytogenetic analysis showed a translocation t(12;14), resulting in structural rearrangement of the region framing the HMGA2 gene at 12q14.3. Such alterations in HMGA2 have been described in both lipomas and pleomorphic adenomas of the salivary glands.
Well-differentiated liposarcomas (WDLPS) and dedifferentiated liposarcomas are cytogenetically characterized by the presence of supernumerary ring or giant chromosomes containing amplified material from the 12q14-15 region. These chromosomes contain neocentromeres, which are able to bind the kinetochore proteins and to ensure a stable mitotic transmission although they do not show detectable alpha-satellite sequences. WDLPS is the sole solid tumor for which the presence of a neocentromere is a consistent and specific feature. By immunostaining with anti-centromere antibodies in combination with FISH analysis (immunoFISH) in four cases of WDLPS, we have shown that sequences from the region 12q14-21 region were not located at the neocentromere site. In addition, we have microdissected the neocentromeric region from a giant supernumerary chromosome in the 94T778 WDLPS cell line. By using immunoFISH and positional cloning we have shown that the neocentromere of this cell line originated from a region at 4p16.1, rich in AT sequences and in long interspersed nucleotide element (LINE)1, that was co-amplified with 12q14-15. We have observed that this 4p sequence was not involved in the neocentromere of the supernumerary giant chromosome present in the 93T449 WDLPS cell line derived from a metachronous recurrence of the same primary WDLPS than 94T778. Altogether, these results indicate that the neocentromeres in WDLPS originate from amplified chromosomal regions other than 12q14-15 and do not involve a specific and recurrent DNA sequence. These sequences might be activated for centromeric function by epigenetic mechanisms.
Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma and rarely occurs in adults. There are six main subtypes, each histologically, clinically, and cytogenetically distinct. Embryonal RMS is characterized by chromosomal gains, usually not associated with any consistent structural anomaly. We describe here a case of embryonal RMS in a 19-year-old female patient. The conventional cytogenetic analysis showed a t(4;22)(q35;q12) translocation as the sole cytogenetic change. Complementary fluorescence in situ hybridization analysis showed that the translocation breakpoints were located in the EWSR1 gene at 22q12 and the region of the DUX4 and FSHMD1A at 4q35. This constitutes a novel example of the high frequency of EWSR1 rearrangements in various types of sarcomas as well as of its ability to fuse with a large variety of partner genes. Because DUX4 is involved in myogenic differentiation and cell-cycle control, the striated muscle differentiation observed in the present case might be a direct consequence of the alteration of the DUX4 region generated by the t(4;22). The involvement of the DUX4 region might represent the genetic hallmark of a novel subclass of small round cell tumors.
To investigate for the first time the immunohistochemical and mutational status of ?-catenin in a mandibular case of adenomatoid odontogenic tumor (AOT) and to review the immunohistochemical expression data of various markers (cytokeratins, metalloproteinases, etc) in such a lesion.
We observed a t(11;22)(q23-24;q11.2-12) and monosomy 3 in renal tumor cells from a 72-year-old man. The hypothesis of a primitive peripheral neuroectodermal tumor (PPNET) located in the kidney was promptly excluded: Histologically, the tumor was a clear cell renal cell carcinoma (RCC) and we did not observe an EWSR1 gene rearrangement. The constitutional origin of this alteration was established. We report on the second case of RCC in a patient with a constitutional t(11;22). The t(11;22)(q23;q11.2) is the main recurrent germline translocation in humans. Unbalanced translocation can be transmitted to the progeny and can cause Emanuel syndrome. Our observation alerts cancer cytogeneticists to the fortuitous discovery of the constitutional t(11;22) in tumor cells. This translocation appears grossly similar to the t(11;22)(q24;q12) of PPNET and should be evoked if present in all cells of a tumor other than PPNET. This is important when providing appropriate genetic counseling. Moreover, the potential oncogenic role of the t(11;22) and its predisposing risk of cancer are under debate. The family history of the patient revealed a disabled brother who died at an early age from colon cancer and a sister with breast cancer. This observation reopens the issue of a link between the constitutional t(11;22) and cancer, and the utility of cancer prevention workups for t(11;22) carriers.
Brain metastases are a frequent and grave complication of non-small cell lung carcinoma (NSCLC). The prognosis is generally poor, despite standard therapy based on surgery and radiotherapy. A degree of understanding of the molecular basis of tumors has led to the development of targeted agents with promising initial findings for the treatment of NSCLC. EGFR mutations have been identified which are associated with significant sensitivity to EGFR tyrosine kinase inhibitors (TKI) and correlate with improved outcome in patients with NSCLC who are treated with these agents. The adoption of treatment tailored to the genetic make-up of individual tumors could lead to substantial therapeutic improvements, and such targeted therapy might be considered as a therapeutic option for brain metastases in the future. We review current knowledge about EGFR mutation status in the specific context of brain metastasis: its association with the response of brain metastases to TKI, its prevalence in brain metastases, and the correlation between mutation status in metastases as compared to the corresponding primary lung carcinoma.
Solitary fibrous tumors (SFTs) are rare spindle cell tumors with limited therapeutic options. Their molecular basis is poorly known. No consistent cytogenetic abnormality has been reported. We used high-resolution whole-genome array-based comparative genomic hybridization (Agilent 244K oligonucleotide chips) to profile 47 samples, meningeal in >75% of cases. Few copy number aberrations (CNAs) were observed. Sixty-eight percent of samples did not show any gene CNA after exclusion of probes located in regions with referenced copy number variation (CNV). Only low-level CNAs were observed. The genomic profiles were very homogeneous among samples. No molecular class was revealed by clustering of DNA copy numbers. All cases displayed a "simplex" profile. No recurrent CNA was identified. Imbalances occurring in >20%, such as the gain of 8p11.23-11.22 region, contained known CNVs. The 13q14.11-13q31.1 region (lost in 4% of cases) was the largest altered region and contained the lowest percentage of genes with referenced CNVs. A total of 425 genes without CNV showed copy number transition in at least one sample, but only but only 1 in at least 10% of samples. The genomic profiles of meningeal and extra-meningeal cases did not show any differences.
Renal medullary carcinoma (RMC), a rare and highly aggressive tumour which occurs in patients with sickle-cell disease, shares many clinicopathological features with collecting duct carcinoma (CDC). The molecular mechanisms underlying RMC and CDC are mainly unknown, and there is ongoing debate about their status as distinct entities. Loss of expression of SMARCB1/INI1, a chromatin remodelling regulator and repressor of cyclin D1 transcription, has been reported recently in RMC. The aim of our study was to investigate if such loss of expression is specific for RMC. SMARCB1/INI1 genetic alterations and cyclin D1 expression were also studied.
While surgery is the usual treatment for localized well-differentiated and dedifferentiated liposarcomas (WDLPS/DDLPS), the therapeutic options for patients with advanced disease are limited. The classical antimitotic treatments are most often inefficient. The establishment of genetically characterized cell lines is therefore crucial for providing in vitro models for novel targeted therapies. We have used spectral karyotyping, fluorescence in situ hybridization with whole chromosome painting and locus-specific probes, and array-comparative genomic hybridization to identify the chromosomal and molecular alterations of a novel cell line established from a recurring sclerosing WDLPS. The karyotype was hypertriploid and showed multiple structural anomalies. All cells retained the presence of a giant marker chromosome that had been previously identified in the primary cell cultures. This giant chromosome contained high-level amplification of chromosomal regions 12q13-21 and lacked the alpha-satellite centromeric sequences associated with WDLPS/DDLPS. The 12q amplicon was large, containing 370 amplified genes. The DNA copy number ranged from 3 to 57. The highest levels of amplification were observed at 12q14.3 for GNS, WIF1, and HMGA2. We analyzed the mRNA expression status by real-time reverse transcription polymerase chain reaction for six genes from this amplicon: MDM2, HMGA2, CDK4, TSPAN31, WIF1, and YEATS4. mRNA overexpression was correlated with genomic amplification. A second amplicon originating from 10p11-14 was also present in the giant marker chromosome. The 10p amplicon contained 62 genes, including oncogenes such as MLLT10, previously described in chimeric fusion with MLL in leukemias, NEBL, and BMI1.
Lipoblastoma is a rare benign adipocytic tumor that occurs usually in children. It can be difficult to distinguish a lipoblastoma from other lipogenic tumors. In such cases, the detection of a rearrangement of the PLAG1 gene by fluorescence in situ hybridization analysis is useful for characterizing a lipoblastoma. We present here a novel case of morphological infantile lipoblastoma showing a rearrangement of HMGA2 instead of the classical PLAG1 alteration. HMGA2 is the main target of clonal aberrations encountered in lipomas. This result supports the hypothesis that benign lipomatous tumors harboring PLAG1 or HMGA2 rearrangement could constitute a unique pathogenetic entity.
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