A SYNOVIAL SARCOMA WITH A COMPLEX T(X 18/5/4) AND A BREAK IN THE ORNITHINE AMINOTRANSFERASE (OAT)LI CLUSTER ON XP11.2/

The initial cytogenetic analysis of a biphasic synovial sarcoma reveal ed complex anomalies involving six different chromosomes: 46,Y,t(X;18; 5;4)(p11;q11;p13;q12),t(2;5)(q35;q11). After fluorescence in situ hybr idization (FISH) analysis, using chromosome X-specific plasmid library and YAC probes, the situation appeared to be even more complex, with an insertion of part of the X chromosome short arm into the der(5)t(5; 18). In spite of these complex chromosomal rearrangements, the Xp11 br eakpoint could be mapped to within the ornithine aminotransferase (OAT )L1 cluster, very similar to that reported previously for the standard t(X;18)(p11;q11) in synovial sarcomas. These findings suggest common pathogenetic pathways in these cytogenetically different but morpholog ically similar tumors. (C) 1994 Wiley-Liss, Inc.