REFINEMENT OF 2 CHROMOSOME-11Q REGIONS OF LOSS OF HETEROZYGOSITY IN OVARIAN-CANCER

Loss of heterozygosity on chromosome 11q23.3-qter is a frequent event in ovarian carcinoma, implying the existence of an important ovarian t umor suppressor gene(s) within the region. To refine a minimum region( s) of loss, 67 ovarian tumors were analyzed for loss of heterozygosity with eight microsatellite markers spanning 11q23.3-qter. Forty tumors (61%) demonstrated allelic losses. Twenty-seven of these had allelic losses on only part of 11q23.3, which enabled the identification of tw o distinct regions likely to harbor ovarian tumor suppressor genes. Th e proximal region, flanked by markers D11S925 and D11S1336, is less th an two megabases while the second more distal region, flanked by marke rs D11S912 and D11S439, is approximately eight megabases. The refineme nt of these candidate tumor suppressor gene loci will facilitate futur e loss of heterozygosity studies and enable the isolation of candidate genes from these regions.