LOCALIZATION OF POTENTIAL TUMOR-SUPPRESSOR LOCI TO A LESS-THAN-2 MB REGION ON CHROMOSOME 17Q IN HUMAN PROSTATE-CANCER

We recently demonstrated a high frequency of loss of heterozygosity (L OH) at the D17S856 and D17S855 (within the BRCA1 gene) loci in primary prostate cancer, suggesting that the BRCA1, gene and/or other tumor s uppressor gene(s) located within the interval of the D17S856 and D17S8 55 loci and/or within the vicinity of this interval may be important i n prostate cancer (Cancer Res., 55: 1002-1005, 1995). To further defin e the exact boundary of the deleted region (i.e., D17S856/D17S855) and to detect other possible LOH regions on the long arm of chromosome 17 , we analysed 23 matched normal and tumor DNAs with 15 polymorphic mic rosatellite markers spanning chromosome 17q12-21. Eleven of 22 (50%) i nformative tumors showed allelic deletion at one or more of the loci s tudied. A minimal area of LOH was identified to extend from the proxim al boundary at the D17S776 locus to the distal boundary at the D17S855 locus, spanning an estimated <2 Mb segment on chromosome 17q21. Our r esults suggest that a potential tumor suppressor gene(s) may reside in the <2 Mb region centromeric (inclusive) to the BRCA1 gene and that t his tumor suppressor gene(s) may be involved in the formation of prost ate cancer.