Fluorescence,Hybridization, Sarcomas,Diagnosis

Soft tissue sarcomas (STS) are rare solid cancers of mesenchymal cell origin accounting for <1% of adult cancers and they represent histologically and molecularly heterogeneous group of tumors. The diagnostics of STS is difficult because of heterogeneity and low incidence, but it is necessary to diagnose the highly malignant sarcomas early and accurately. Specific genetic findings as translocations of SS18, COL1A/PDGFB, EWSR1, DDIT3 genes have been found in 30% STS, and they can be detected by fluorescence in situ hybridization (FISH). Between January 2014 and January 2017, in our laboratory, 17 formalin-fixed, paraffin-embedded (FFPE) tissues were examined by FISH using probes: Kreatech ON SYT (18q11) Break, ON EWSR1 (22q12) Break, ON CHOP (12q13) Break, ZytoVysion SPEC COL1A1/ PDGFB Dual color. A total of 17 cases were evaluated, namely a Ewing sarcoma (7 cases), Synovial sarcoma (8 cases), Liposarcoma (1) and Dermatofibrosarcoma (1). Rearrangements of investigated genes were identified in 11 samples (64,7%): rearrangement of SS18 in 3 cases of synovial sarcoma, rearrangement of EWSR1 in 4 cases of Ewing sarcoma, rearrangement of genes COL1A1/PDGFB in one case of dermatofibrosarcoma and rearrangement of gene DDIT3 in one case of liposarcoma. In 2 cases of suspect Ewing sarcoma with rearrangement of EWSR1 the final histopathological diagnosis were olfactory neuroblastoma and extraskeletal myxoid chondrosarcoma; this genetic change in both diagnosis has been described in literature before. 6 FISH negative cases (35,3%) were reported as stromal endometrial carcinoma, malignant peripheral nerve sheath tumor, leiomyosarcoma, adenocarcinoma, sarcomatoid carcinoma. Rearrangements of investigated genes have been identified by FISH in 64,7% cases, the findings were corresponding with the final diagnosis and with literature.