Defining Ewing and Ewing-like small round cell tumors (SRCT): The need for molecular techniques in their categorization and differential diagnosis. A study of 200 cases.

BACKGROUND: Differentiation of Ewing sarcoma family of tumors (ESFT) and Ewing-like tumors remains problematic. Certain ESFT with morphological and immunohistochemical (IHC) profiles lack the EWSR1-ETS transcript. To improve diagnostic accuracy we investigated the presence of several specific transcripts in 200 small round cell tumors (SRCT) displaying ESFT morphology and immunophenotype in which EWSR1 FISH analysis was non-informative or negative. DESIGN: 200 tumors (formalin-fixed, paraffin-embedded) were analyzed by RT-PCR. All tumors were tested for EWSR1-ETS, EWSR1/WT1, PAX3/7-FOX01 or SYT/SSX transcripts, and the negative tumors were subsequently analyzed for CIC/DUX4, BCOR/CCNB3 and CIC/FOX04 transcripts. RESULTS: 133 (66.5%) ESFT displayed one of the above EWSR1-ETS translocations. Three cases (1.5%) revealed the SYT-SSX transcript for Synovial sarcoma, and one (0.5%) a EWSR1-WT1 transcript for Desmoplastic Small Round Cell tumor. The CIC-DUX4 translocation was found in six Ewing-like tumors (3%) with CD99 positivity. The BCOR-CCNB3 gene fusion was observed in 5 tumors (2.5%) displaying round or spindle cells with strong CCNB3 IHC expression in 3 tumors. Moreover, RT-PCR failed to detect any gene fusion transcripts in 19 tumors (9.5%) and were considered "undifferentiated small round cell sarcoma" (SRCS). Molecular biology results were non-informative in 33 SRCTs (16.5%) due to RNA degradation through inadequate fixation and/or decalcification. CONCLUSION: Our analysis of 200 SRCTs confirms the molecular heterogeneity of neoplasms with ESFT morphology and highlight that molecular studies with RT-PCR including new emerging gene fusion transcripts are mandatory for the diagnosis when EWSR1 FISH is negative or non-informative. The incidence of CIC-DUX4, BCOR-CCNB3 and CIC-FOX04 transcripts was relatively low. A small group of Ewing-like sarcomas or undifferentiated SRCS remains unclassified. Adopting appropriate tissue fixation and processing protocols is important to avoid degradation of fixed/embedded tissue when no frozen tumor is available.

Clinicopathological significance of cell cycle regulation markers in a large series of genetically confirmed Ewing's sarcoma family of tumors.

More than 90% of all Ewing's Sarcoma Family of Tumors (ESFT) exhibit specific chromosomal rearrangements between the EWS gene on chromosome 22 and various members of the ETS gene family of transcription factors. The gene fusion type and other secondary genetic alterations, mainly involving cell cycle regulators, have been shown to be of prognostic relevance in ESFT. However, no conclusive results have been reported. We analyzed the clinicopathological significance of relevant cell cycle regulators in genetically confirmed ESFT. A total of 324 cases were analyzed for the immunohistochemical expression of p53, p21(Waf1/Cip1) , p27(Kip1) and Ki67 and the chromosomal alterations of the p53 and 9p21 locus by fluorescent in situ hybridization. We observed that expression of p53 (p = 0.025), p21(Waf1/Cip1) (p = 0.015) and p27(Kip1) (p = 0.013) was higher in disseminated than in localized disease. Furthermore, a cohort of 217 patients with localized disease was considered for studying the prognosis involvement of these factors on patient follow-up. The median follow-up was 39 months (range: 0.17-452) with an overall survival (OS) of 55%. Ki67 was expressed in 34% of cases and constituted an independent prognostic factor for progression free survival and OS independently of the type of treatment [hazard ratio of 2.0 (95% CI: 1.3-3.1; p = 0.003) and 1.9 (95% IC: 1.3-2.9; p = 0.007) for progression free survival and OS, respectively, being especially relevant in the group of patients which incorporated radiotherapy in their regimen schedules. In conclusion, this study demonstrates that Ki67 expression constitutes a valuable indicator of poor prognosis in localized ESFT.

Dermatofibrosarcoma protuberans: a clinicopathological, immunohistochemical, genetic (COL1A1-PDGFB), and therapeutic study of low-grade versus high-grade (fibrosarcomatous) tumors.

BACKGROUND: Dermatofibrosarcoma protuberans (DFSP) is an uncommon cutaneous tumor, usually low grade, except for the fibrosarcomatous variant (DFSP-FS). OBJECTIVES: We sought to compare the clinicopathological, immunohistochemical, genetic, and therapeutic features between DFSP and DFSP-FS. METHODS: The clinicopathological features were reviewed in 63 DFSP and 12 DFSP-FS. Immunohistochemistry and multiplex reverse transcriptase-polymerase chain reaction were carried out using formalin-fixed, paraffin-embedded tissue, using specific primers for collagen type I alpha 1 (COL1A1) and platelet-derived growth factor beta (PDGFB). RESULTS: DFSP-FS was associated with tumor history longer than 5 years (P = .009), tumor size greater than 4 cm (P = .001), more stages of modified Mohs micrographic surgery (P = .005), expansive subcutaneous infiltration (P = .005), muscular invasion (P = .0001), absence of CD34 staining (P = .018), p53 positivity (P = .006), and increased proliferative activity (P = .004) compared with DFSP. The COL1A1-PDGFB fusion transcript was found in 100% DFSP-FS and 72% DFSP. No association was found between the different COL1A1-PDGFB fusion transcripts and the different histologic subtypes. Wide local excision (2 cm) was performed in 47% of cases and modified Mohs micrographic surgery in 53%. After a mean follow-up of 73 months (range 21-235), 6 patients had local recurrence (5 DFSP, 1 DFSP-FS) and one died of disease (DFSP-FS). The only factor related to local recurrence was the type of surgery (17% wide local excision vs 0% modified Mohs micrographic surgery) (P = .006). LIMITATIONS: Our study is retrospective. Prospective studies are necessary to confirm our results. CONCLUSIONS: DFSP-FS reflects tumor progression in DFSP, with larger size, particular invasive patterns, p53 expression, and increased proliferative activity. However, as in low-grade DFSP, appropriate surgery permits a tumor-free excision. COL1A1-PDGFB is a useful tool for diagnosis of DFSP and particularly for DFSP-FS.

New approaches in the diagnosis of small-cell round tumors of bone and soft tissue.

The diagnosis of 17 small-cell round tumors of the bone and soft tissue, which were histologically similar to Ewing's sarcoma (EWS), was verified on paraffin sections, by using tissue microarray (TMA) technology, immunohistochemistry, cytogenetic (FISH) and molecular biological (RT-PCR) methods. Classical EWS was found to be in 8 patients, large-cell EWS in 1 patient; atypical EWS in 1, and endothelial ESW in 1. Two patients were diagnosed as having primitive neuroectodermal tumor (PNET), synovial sarcoma was present in 1 patient, embryonic rhabdomyosarcoma in 1, high-grade undifferentiated sarcoma in 1 and diffuse B-cell large-cell lymphoma in 1. TMA makes it possible to perform a number of diagnostic procedures on the same block containing a copious number of tumor samples and to assess the results of their use. It is emphasized that the diagnosis of small-cell round tumors requires the use of a package of the currently available methods providing the qualitative characteristics of each neoplasm.

Evaluation of genetic stability of the SYT gene rearrangement by break-apart FISH in primary and xenotransplanted synovial sarcomas.

Synovial sarcomas (SS) are infrequent and morphologically heterogeneous soft tissue sarcomas. The t(X;18)(p11.2;q11.2), which results in fusion of the SYT gene at 18q11 with the SSX1, SSX2, or (rarely) SSX4 gene is a primary genetic event in 90% of SS. To determine whether the t(X;18) present in the original tumor is maintained in its passages, a dual-color break-apart FISH assay for SYT gene disruption was performed in two tissue microarrays (TMA) comprising eight molecularly confirmed primary SSs and their xenografts, which were followed for several generations. A simplified scoring system was applied to the FISH results of the primary and xenotransplanted SS to classify the FISH data into distinct groups. SYT disruption was identified in all eight primary SS and in all their passages without any significant differences among them, despite wide variations in xenotransplantation time between the primary tumors and their xenografts. The TMA-based FISH assay demonstrated genetic stability related to SYT gene rearrangement in primary and xenografted SS.

Prognostic value of the International Neuroblastoma Pathology Classification in Neuroblastoma (Schwannian stroma-poor) and comparison with other prognostic factors: a study of 182 cases from the Spanish Neuroblastoma Registry.

In addition to clinical and biological factors, further valuable prognostic information in neuroblastoma (Schwannian stroma-poor) (NB) patients is provided by the histopathologic analysis and the application of the International Neuroblastoma Pathology Classification (INPC) system. The objective of this study was to assess the prognostic impact of the INPC classification in a series of NB (Schwannian stroma-poor) and its relation with other prognostic factors. One hundred eighty-two cases of NB were collected from the files of the Spanish Neuroblastoma Registry. Slides were reviewed, and NB cases were grouped into favorable and unfavorable categories according to INPC criteria, taking into account morphological features (mitosis-karyorrhexis index, histological subtype) and patient's age at diagnosis. Other pathological [presence of calcifications, tissular components, and number of mitotic cells per 10 high-power field (HPF)], immunohistochemical (P-glycoprotein and Ki-67 protein expression) and genetic (MYCN amplification and chromosome 1p deletion) features were also studied. Statistical analyses of overall survival with Kaplan-Meier curves and a multivariate study using Cox regression were performed (40.3% of NBs were considered favorable and 59.7% unfavorable). Unfavorable NB showed a mean survival time of 57 months compared with 89 months in favorable cases. Advanced stage, more than ten mitoses per 10 HPF, Ki-67 expression in more than 30% of tumor cells, MYCN oncogene amplification and chromosome 1p deletion were observed more frequently in unfavorable NB. The Cox regression analysis demonstrated that clinical stage (International Neuroblastoma Staging System stage 4) and histological subtype (undifferentiated NB) were the most important factors that influence the overall survival (p<0.001). INPC classification results are major prognostic indicators in NB and should be considered in the therapeutic stratification of NB patients.

Tissue microarray profiling of primary and xenotransplanted synovial sarcomas demonstrates the immunophenotypic similarities existing between SYT-SSX fusion gene confirmed, biphasic, and monophasic fibrous variants.

This paper discusses the diversity of synovial sarcomas (SSs) [biphasic (BSS), monophasic fibrous (MFSS), and poorly differentiated (PDSS)] and tissue microarray (TMA) evaluation of the immunophenotypic and histological progression of SSs in nude mice using three TMAs comprising 11 primary SSs (8 MFSSs, 2 BSSs, and 1 PDSS) and their xenografts. BSS and MFSS progressively transformed to a similar undifferentiated phenotype with loss of glandular component in the xenografts. Epidermal growth factor receptor and SALL2 were expressed in primary tumors and xenografts. Enhanced bcl-2 and bax expression were noted in xenografts. Ki-67 overexpression in xenografts correlated with high mitotic index. Epithelial membrane antigen (EMA) and cytokeratin AE1/AE3 were detected in all original and xenografted SSs. Hierarchical clustering differentiated original MFSS and BSS, but their xenografts clustered together due to similar immunoexpression profile. Our study demonstrates definite phenotypic variability of BSS and MFSS in the xenografts. Differences in immunoexpression for various markers existed between primary tumor and xenografts but not between subtypes. Hierarchical clustering grouped TMA immunostaining data and confirmed immunophenotypic variability; however, it failed to reveal any immunophenotypic differences between SYT-SSX1 and SYT-SSX2 type tumors. Nonetheless, reverse-transcriptase-polymerase chain reaction detected SYT-SSX transcripts in all primary SSs and their xenografts, thereby demonstrating their genetic stability.

Mutational analysis of the c-KIT AND PDGFRalpha in a series of molecularly well-characterized synovial sarcomas.

The c-KIT and the platelet-derived growth factor receptor alpha (PDGFRalpha) have been shown to be important for tumor growth and progression in several soft-tissue sarcomas, including synovial sarcomas (SSs). It has been suggested that these c-KIT-positive cases might benefit from a tyrosine kinase inhibitor therapy. In this study, we analyze a series of SSs to investigate the presence of c-KIT and PDGFRalpha mutations with the aim of selecting those for a more adequate and appropriate therapy. We analyzed fresh-frozen tissues from 12 SSs (8 primary tumors and 4 nude mice xenotransplants from primary tumors). RNA was extracted to identify the presence of the SYT-SSX gene fusion to confirm the SS diagnosis. Mutational analysis of exons 9, 11, 13, and 17 of c-KIT and exons 12 and 18 of PDGFRalpha was performed by direct sequencing. Immunohistochemical analysis of c-KIT, PDGFRalpha, and p-PDGFRalpha was also performed. All analyzed cases showed the presence of SYT-SSX gene fusion transcripts confirming the diagnosis of SS, 10 carried the SYT-SSX1 fusion, and 2 the SYT-SSX2. Immunohistochemical analysis showed expression of c-KIT in 3 cases in which no molecular alterations were detected. For the PDGFRalpha, we observed an in-frame deletion of codons 554 and 555 in a case which also showed a strong immunopositivity for the phosphorylated form of PDGFRalpha. PDGFRalpha expression was observed in 8 cases. We suggest that a more exhaustive mutational analysis of the c-KIT and PDGFRalpha genes should be performed to ascertain which cases would really benefit from a tyrosine kinase inhibitor therapy in SS.

Deregulation of glyceraldehyde-3-phosphate dehydrogenase expression during tumor progression of human cutaneous melanoma.

BACKGROUND/AIM: Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a highly abundant housekeeping gene. GAPDH overexpression has been reported in diverse types of human cancers including cutaneous melanoma. Our goal was to quantify GAPDH mRNA and protein expression in the whole spectrum of primary and metastatic melanomas in the search for a specific role for this ubiquitous molecule during tumor progression. MATERIALS AND METHODS: Intratumoral GAPDH mRNA expression was quantified by real-time PCR in 71 cases, including 29 primary melanomas and 42 metastatic cases. Relative expression levels in thin (≤1 mm) and thick (>1 mm) primary tumors and 'in-transit', lymph node and distant metastases were compared. Similarly, protein expression was investigated by means of immunohistochemistry. Specific exons of GAPDH were analyzed by DNA sequencing. RESULTS: GAPDH mRNA expression was significantly up-regulated in thick melanomas when compared to primary thin melanomas. Similar differences were also encountered between metastatic melanomas when compared to lymph-node metastatic melanomas. Interestingly, GAPDH protein immunoexpression was higher in thick melanomas and distant metastases than in thin tumors and lymph node metastases, respectively. However, no specific point-mutations in GAPDH-specific exons were found in any patient. CONCLUSION: Deregulation of GAPDH during melanoma progression was demonstrated in our series by mRNA and protein expression studies.

Ewing-like sarcoma with CIC-DUX4 gene fusion in a patient with neurofibromatosis type 1. A hitherto unreported association.

Sarcoma with CIC-DUX4 gene fusion is emerging as the most prevalent subset of Ewing-like undifferentiated small round cell sarcomas with around 50 cases published. We report hereby the case of a 40-year-old male who presented a CIC-DUX4 sarcoma in deep soft tissues in his thigh. He had been diagnosed with neurofibromatosis type 1 at age 19 and over the years underwent resection of multiple neural neoplasms, including two malignant peripheral nerve sheath tumors with classical spindle-cell histopathology. The CIC-DUX4 sarcoma was treated with surgical resection, radiation and chemotherapy, but lung and brain metastases developed and the patient died from the disease 14 months after diagnosis. This is the first case of sarcoma with CIC-DUX4 gene fusion reported in a patient with NF1. Whether this association is coincidental or CIC-DUX4 sarcomas could be related to NF1 remains to be clarified. Study of alternative molecular alterations in EWSR1-negative undifferentiated small round cell sarcomas is clinically relevant, since CIC-DUX4 sarcomas seem to be a very aggressive subset with poor response to the presently used therapeutic regimens.

The INK4a /ARF locus: role in cell cycle control for renal cell epithelial tumor growth after the Chernobyl accident.

Previous studies have shown that during the period subsequent to the Chernobyl accident, increases in morbidity, aggressivity and proliferative activity of renal-cell carcinomas (RCCs) in Ukrainian patients were recognized. The present paper describes the molecular alterations of those tumor suppressor genes located on chromosome 9p21 ( INK4a/ARF locus and p15(INK4B)) in 26 primary renal-cell epithelial tumors from patients with different degrees of radiation exposure after the Chernobyl accident in Ukraine. Radiometric measurement of Cesium 137 ((137)Cs) was conducted with 1-day urine from all patients before surgery. Our results demonstrate that RCCs from patients living in the radio-contaminated areas showed aberrant hypermethylation of p14(ARF) and p16(INK4A) genes, associated with increased p38MAPK, p14(ARF), mdm2, cyclinD1 and Ki67 protein expression levels. Present findings show the possibility that chronic long-term low-dose radiation activates the INK4a/ARF locus, targeted by activation of the p38MAPK cascade. These actions could lead to disruptions and loss of cell cycle checkpoints and, thereby, to cellular transformation.

Deregulation of the G1 to S-phase cell cycle checkpoint is involved in the pathogenesis of human osteosarcoma.

Osteosarcoma (OS) displays complex karyotypes with numerical changes as well as structural abnormalities suggesting that several oncogenes and tumor suppressor genes may be implicated in the biology of OS. The aim of our study was to investigate the possible implication of the molecular alterations of the G1 to S-phase checkpoint genes in the pathogenesis of OS. We analyzed samples from 29 patients and found molecular alterations of the RB and TP53 genes in 6 (21%) and 3 (10%) cases, respectively. Homozygous deletion of the INK4A/ARF locus and methylation of INK4A was detected in 3 (10%) and 2 (7%) cases, respectively. CDK4 and MDM2 co-amplification was observed in 1 case (3%). Cyclin D3 is differentially expressed in a greater proportion than D1- and D2-type cyclins. Cytogenetically, all cases had complex karyotypes being especially significant the losses of the chromosomes 4, 13, and 17. As a whole, 11 of 29 (38%) analyzed OS presented alterations in some of the analyzed G1 to S-phase checkpoint genes. These alterations were more frequently present in adults (P = 0.032). All patients with genetic alterations in the G1/S-phase checkpoint died during their clinical follow-up, whereas more than 53% of the remaining cases were alive in this period (P = 0.007). Hence, in the pathogenesis of human OS, deregulation of the G1/S checkpoint genes, especially RB, TP53, and INK4/ARF locus, plays an important role and defines a subgroup of patients with a poor outcome.

P16INK4A and p15INK4B gene alteration associated with oxidative stress in renal cell carcinomas after the chernobyl accident (pilot study).

Our study was undertaken to better understand the role of G1/S transition abnormalities in the malignant progression of renal cell carcinomas (RCCs), exposed to long-term low doses of ionizing radiation (IR), from patients living in radiocontaminated areas of the Ukraine after the Chernobyl accident. We studied p16 and p15 gene alteration in association with oxidative stress markers, including inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2). We analyzed 88 samples collected from 22 patients with RCCs and with different exposure to IR. Homozygous deletion of the p16 and p15 genes, as well as hypermethylation of the 5CpG island in the promoter region of the same genes, were analyzed by differential PCR and Methylation-Specific PCR respectively, in association with histopathology and immunohistochemical analysis of p16 and p15 proteins. COX2 and iNOS expression in the same tumors were likewise analyzed. Aberrant hypermethylation was observed in 7 (32%) and 5 (23%) cases accompanied, by immunohistochemical loss of expression for p16 and p15 genes respectively, in both high stage and grade tumors from patients living in radiocontaminated areas, this being especially outstanding for the p16 gene. An association with COX2 and less iNOS overexpression in the same tumors was observed. Our data suggest that inactivation of p16 gene, but not p15, induced by increased oxidative stress generated by persistent chronic exposure to IR, could be one of the major pathways responsible for RCCs malignant progression.

MYCN gain and MYCN amplification in a stage 4S neuroblastoma.

Stage 4S neuroblastoma is a disease associated with spontaneous regression and good survival. We present a patient whose evolution has shown the variety and complexity of this disease in infants. Biologic factors, such as ploidy, MYCN copy number, loss of 1p36, and other chromosomal gains and losses were determined. A complex pattern of genetic abnormalities, such as near-diploidy, MYCN gain (2-4 copies per haploid genome) and imbalance/deletion of 1p36 was seen in the diagnostic sample. An extensive disseminated disease after a latent period of 26 months was associated with a special genetic evolution, such a tetraploidy, MYCN amplification (2:100-500 copies), 1p36 deletion, and gain of 17q. Our results provide evidence that either the primary tumor was heterogeneous in terms of gene amplification or that amplification was acquired later on as a transition from MYCN gain. We suggest that near-di-/tetraploid 4S tumors with MYCN gain and/or deletion 1p could be progressing 4S tumors.

Prognostic significance of cell proliferation in human neuroblastoma: comparison with other prognostic factors.

Peripheral neuroblastic tumors (PNT), are heterogeneous neoplasms that include neuroblastoma (NB), ganglioneuroblastoma (GNB) and ganglioneuroma (GN) and present great biological heterogeneity. There are few reports analyzing PCNA and Ki-67 expression in PNT; however, controversy exists concerning the specificity of PCNA as a real proliferative marker. The objective of our study was to determine which of these cellular proliferation markers is more specific on cellular cycle and could contribute with more information on the cell cycle. We found that PCNA was expressed in NB unfavourable cases, with MYCN amplification and high mitosis-karyorrhexis-index (MKI). Whereas, Ki-67 showed statistical significance regarding cases unfavourable with intermediate and high MKI, aneuploid and stages 3 and 4. Survival showed that patients with tumor not expressing Ki-67 (MIB1) lived longer than those without PCNA (88.93 vs 74.05%). We conclude that Ki-67 expression permits reliable detection of the cellular proliferation neuroblastoma fraction and provides useful prognostic information when associated with other biological factors.

Study of proliferation and apoptosis in neuroblastoma. Their relation with other prognostic factors.

BACKGROUND: Our objective was to study the proliferation and apoptotic process in 111 cases of neuroblastoma (NB) and to seek their relationship with other prognostic factors and survival. METHODS: Immunohistochemistry following ABC peroxidase was carried out for PCNA, Ki-67, bcl-2, and p53 proteins. Apoptosis analysis was performed with in situ detection of chromosomal breakdown. Molecular detection of DNA ladders by electrophoresis and amplification of MYCN was studied with PCR and Southern blot. Statistical study was performed with Pearson chi(2) and Kruskal-Wallis tests and Cox regression. RESULTS: Our results indicate that proliferative factors PCNA and Ki-67 were correlated to each other as well as to advanced stage and MYCN amplification. Regarding apoptosis, we found expression of bcl-2 protein in cases of NB without differentiation and advanced stages. p53 protein showed an inverse relation with bcl-2 and cell death measured by assay protein. In situ determination of apoptosis was found mainly in differentiated and stage 4s cases. Multivariate analysis revealed protein as the most independent risk factor of our study. CONCLUSIONS: The study of cellular proliferation and apoptosis contributes with information of prognostic value that could be applied to the design of different protocols for treatment of neuroblastoma.

Histological tumor grade correlates with HER2/c-erB-2 status in invasive breast cancer: a comparative analysis between immunohistochemical (CB11 clone and Herceptest), FISH and differential PCR procedures.

There is a growing clinical demand for analysis of the HER2/c-erbB-2 (HER2) status of breast cancer specimens because it provides valuable prognostic, predictive and therapeutic information. In this sense, a variety of methods is available for detection of HER2 status, although to date a reliable and sensitive test does not exist. In order to choose the most suitable procedure to assess HER2 status, we analyzed 102 invasive breast cancers for HER2 overexpression by means of immunohistochemistry (IHC), with the CB11 Mo-Ab and the Hercep Test kit, and for HER2 gene amplification by fluorescence in situ hyubridization (FISH) and differential PCR (dPCR). HER2 overexpression, determined by CB11 (group C) and HercepTest (2+ and 3+), was observed in 19 samples (18.6%) whereas genetic amplification was detected in 31 (30.4%) and 14 (13.7%) cases by FISH and dPCR, respectively. The majority of overexpressed/amplified specimens corresponded to high grade tumors. We found concordances of 78-80% and 93-95% between IHC vs FISH and IHC vs dPCR, respectively. Considering FISH procedure as a gold standard, we found a sensitivity and specificity of 48.4% and 94.3% for CB11 antibody, of 45.2% and 92.9% for HercepTest, and of 45.2% and for 100% for the dPCR. Thus, considering the sensitivity, specificity and the high grade of concordance between IHC and dPCR, we suggest the use of IHC for assessing HER2 status. However, due that sensitivity of IHC test is lower than FISH, we also suggest to carry out FISH on those cass in which IHC results are not definitive for its clinical evaluation.

Characterization of a new human cell line (CH-3573) derived from a grade II chondrosarcoma with matrix production.

Chondrosarcomas are malignant cartilage-forming tumors that represent the third most common malignant solid tumor of bone. In patients with grades II and III, local recurrence, increasing tumor size and dedifferentiation have been associated with lower survival rates. These biologically poorly-understood neoplasms vary considerably in clinical presentation and biological behavior. Cytogenetic studies have shown that heterogeneity is related to karyotypic complexity; moreover, alterations in the 9p21 locus and TP53 gene are related to disease progression. Despite the relatively high frequency of chondrosarcoma only a limited number of cell lines exist in the scientific community, limiting the possibility to study hypothesis-derived research or primary drug interaction necessary for pre-clinical studies. We report a chondrosarcoma cell line, CH-3573, derived from a primary tumor that may serve as a useful tool for both in vitro and in vivo models to study the molecular pathogenesis. In addition, xenograft passages in nude mice were studied to characterize the genetic stability over the course of tumor progression. In contrary to other reported cell lines, an important feature of our established cell line was the retained matrix production, a characteristic feature of a conventional grade II chondrosarcoma. The cell line (CH-3573) was characterized by pathological, immunohistochemical and molecular genetic methods.