GENETIC IMBALANCES IN 67 SYNOVIAL SARCOMAS EVALUATED BY COMPARATIVE GENOMIC HYBRIDIZATION

We used comparative genomic hybridization (CGH) to evaluate DNA sequen ce copy number changes in 67 synovial sarcomas of both monophasic and biphasic histological subtypes, Changes (mean among aberrant cases: 4. 7 aberrations/tumor; range: 1-17), affecting most often entire chromos omes or chromosome arms, were detected in 37 sarcomas (55%). Gains and losses were distributed equally, but different chromosomes were affec ted with variable frequencies. The most frequent aberrations, each det ected in 9-11 of 67 tumors, were gain of 8q and gain at 12q (12q14-15 and 12q23-qter), loss of 13q21-31, and loss of 3p. Other frequent chan ges (in 7 or 8 cases) included gains at 2p, 1q24-31, and 17q22-qter, a nd losses at 3cen-q23 and 10q21. High-level amplifications were seen i n 7 cases. A total of 16 regions were detected. Two of them, 8p12-qter and 21q21-qter, seen in 4 and 2 tumors, respectively, were recurrent. No aberrations specific to histological subtype were identified, Howe ver, genetic changes in the monophasic tumors were more complex and nu merous (mean among aberrant cases: 5.3 aberrations/tumor; range: 1-17) than in the biphasic tumors (mean: 2.5 aberrations/tumor; range: 1-5) , and high-level amplifications occurred more frequently. All but I of the sarcomas showing high-level amplification were of the monophasic subtype. These findings may reflect differences in the pathogenesis an d biological behavior of both histological subtypes of synovial sarcom a. Genes Chromosomes Cancer 23:213-219, 1998. (C) 1998 Wiley-Liss, Inc .