Cytogenetic Findings in Two Synovial Sarcomas J. Limon, K. Mr6zek, B. Nedoszytko, M. Babibska, J. Ja~kiewicz, A. Kopacz, A. 7.bltowska, and J. Borowska-Lehman ABSTRACT: Cytogenetic analysis was perJormed after short-term tissue culture of two recurrent syn- ovial sarcomas. The tumors were classified on the basis of morphology, location, and immuno- histochemistry. In a poorly differentiated tumor, the karyotype 49,XY,+7,+8,+lg,tfS;18J (qll.2;q11.2), and in a biphasic tumor two clonal cell lines with common translocations t(X;18)(pl 1.2;q11.2] and t(12;17J(p11.2;qll.2J were present. In the predominant cell line sev- eral other structural aberrations including t(1;12)(q21;q24.3), t(3;18)(p23;q21), and 17p+ were found. A comparison of our results with previously published studies suggests that in addition to t{X;18), translocations of chromosome 18 with other chromosomes may represent a consis- tent feature of chromosomal changes in synovial sarcoma. INTRODUCTION Cytogenetic studies of soft tissue tumors have revealed specific aberrations in adi- pose tissue sarcomas [1-3], rhabdomyosarcomas [4], synovial sarcomas [5-11], and Ewing's sarcoma [12]. The translocation t(X;18)(p11.2;q11.2) was common for 12 cases of monophasic spindle cell and biphasic types or poorly differentiated sarco- mas [6-11]. However, the same translocation was observed in single cases of malig- nant fibrous histiocytoma [6] and fibrosarcoma [13]. We present herein reports on two cases of synovial sarcoma that, in addition to other numerical and structural aberrations, displayed translocations of chromosome 18. In the case of the biphasic synovial sarcoma the translocation t(X;18) was found. In the case of a poorly differen- tiated synovial sarcoma, chromosome 18 was involved in translocation with chromo- some 5. The breakpoint on chromosome 18 was the same as the one in the well- known translocation, t(X;18). From the Departments of Biology and Genetics (J. L., K. M., B. N., M. B.), Oncological Surgery (J. J., A. K.), and Pathomorphology (J. B.), and the Laboratory of Immunology (A. Z.), Medical Academy, Gda~sk, Poland. Address reprint requests to: Dr. lanusz Limon, Department of Biology and Genetics, 1 Debinki St., 80-211 Gda~sk, Poland. Received July 22, 1988; accepted November 3, 1988. 215 © 1989 Elsevier Science Publishing Co., Inc, 655 Avenue of the Americas, New York, NY 10010 Cancer Genet Cytogenet 38:215-222 (1989) 0165-4608/89/$03.50