MOLECULAR CHARACTERIZATION OF MAR, A MULTIPLE ABERRATION REGION ON HUMAN-CHROMOSOME SEGMENT 12Q13-Q15 IMPLICATED IN VARIOUS SOLID TUMORS

Chromosome arm 12q breakpoints in seven cell lines derived from primar y pleomorphic salivary gland adenomas were mapped by FISH analysis rel ative to nine DNA probes. These probes all reside in a 2.8 Mb genomic DNA region of chromosome segment 12q13-q15 and correspond to previousl y published sequence-tagged sites (STS). Their relative positions were established on the basis of YAC cloning and long range physical and S TS content mapping. The 12q breakpoints of five of the cell lines were found to be mapping within three different subregions of the 445 kb D NA interval that was recently defined as the uterine leiomyoma cluster region of chromosome 12 breakpoints (ULCR12) between STS RM33 and RM9 8. All seven breakpoints appeared to map within the 1.7 Mb DNA region between STS RM36 and RM 103. Furthermore, the chromosome 12 breakpoint s of three primary pleomorphic salivary gland adenomas were also found to be mapping between RM36 and RM 103. Finally, FISH analysis of two lipoma cell lines with 12q13-q15 aberrations pinpointed the breakpoint s of these to relatively small and adjacent DNA segments which, as wel l as those of two primary lipomas, appeared to be located also between RM36 and RM 103. We conclude from the observed clustering of the 12q breakpoints of the three distinct solid tumor types that the 1.7 Mb DN A region of the long arm of chromosome 12 between RM36 and RM103 is a multiple aberration region which we designate MAR. (C) 1995 Wiley-Liss , Inc.