Complex tumor-specific t(X;18) in seven synovial sarcoma tumors.

Cytogenetic analysis was performed of six monophasic synovial sarcomas (four primary, two recurrent tumors) and one recurrent poorly differentiated synovial sarcoma with complex tumor-specific t(X;18). In the complex translocations, besides chromosomes X and 18, the following chromosomes were involved: 1, 3, 5, 15, and 17. In all, taking these results together with findings of 20 previously published synovial sarcoma tumors with complex t(X;18), 13 different chromosomes were involved. Chromosomes 15 (22% of tumors) and 1, 5, and 12 (approximately 11% each) were the most frequently involved in complex translocation, but with different breakpoints. In our laboratories, complex tumor-specific t(X;18) ranged from 2.5% to 11.7% (average 6.5%) of synovial sarcoma karyotypes.