• chromosomal translocation;
  • fluorescence in situ hybridization;
  • paraffin-embedded tissue;
  • soft tissue sarcoma

In soft tissue sarcomes, clonal rearrangement of chromosomes has been shown by cytogenetic analysls to be unique and specific for tumor types. The development of fluorescence in situ hybridbation (FISH) has allowed detection of chromosomal rearrangements In the interphase nuclel isolated from paraffin-embedded tissues. Three kinds of trans-locations in the interphase nuclel that were isolated from 47 cases of soft tissue sarcomas ware examined by FISH with chromosome-speclfic DNA probes of centromeric and total probes. of 47 soft tissue sarcomas 42 (89.4%) revealed tumor-specitic transiocations by retrospective cytogenetic analysis. Transiocation t(X;18) was detected In 25/28 synovial sarcomas; translocation t(11;22) In 5/6 Ewlng's sarcomas and primitive neuroectodermal tumors (PNET); and translocation t(12;16) was found in 12/13 liposarcomas, including 10 myxold and two round cell lypes as clonal chromosomal aberrations specific for both subtypes. Based on the cytogenetic analysis, Ewing's sarcoma is related closely with PNET as shown by MIC2–protein reactivity. Other cytogenetic findings of translocation t(12;16) Indicate that round cell liposarcomas share chromosomal changes with myxoid lipo sarcomas, and further suggest that both tumor subtypes of liposarcoma may possess common precursor cells. FISH is a useful aid in determining the tumor type of soft tissue sarcomas with regard to histogenetic origin.