AT LEAST 2 DIFFERENT REGIONS ARE INVOLVED IN ALLELIC IMBALANCE ON CHROMOSOME ARM 16Q IN BREAST-CANCER

Loss of heterozygosity (LOH) or allelic imbalance, the latter term ref erring to both loss and gain of an allele, on the long arm of chromoso me 16 has been repeatedly found in cancers of, e.g., the breast and pr ostate. This indicates the presence of one or more tumor suppressor ge nes on 16q. To locate the gene(s) more precisely, a detailed allelic i mbalance map of 20 polymorphic markers on this chromosome arm was made for 79 sporadic breast carcinomas. LOH of one or more markers was fou nd in 63% of the tumors. Some had allelic imbalance on a region of 16q which failed to overlap with the LOH in other tumors. We therefore as signed two separate ''smallest regions of overlap'' to 16q and suggest that this chromosome arm contains at least two different tumor suppre ssor genes. (C) 1994 Wiley-Liss, Inc.