MICROSATELLITE INSTABILITY IN ORAL-CANCER

Generalized genomic instability, detected as somatic changes in allele sizes at microsatellite loci in tumors compared to peripheral lymphoc yte DNA, is a recently recognized mechanism of mutation in cancer. Suc h instability results from the somatic loss of DNA mismatch repair cap ability. Germ-line mutations at DNA mismatch repair loci confer suscep tibility to colon cancer in hereditary non-polyposis colorectal cancer . Somatic loss of DNA mismatch repair has been reported in a large var iety of other tumor types. Our goal was to determine the frequency of microsatellite instability in a large series of oral tumors. Out of 91 tumors analyzed for microsatellite instability, 6 (7%) showed microsa tellite instability. Instability was observed at multiple loci with a range of 50-74% of loci affected. Alterations include both increase (7 4%) and decrease (26%) in allele sizes. The proportion of alleles affe cted ranged from 30-58% of all alleles. Our data suggest that somatic genomic instability plays a role in the pathogenesis of a small subset of oral tumors. (C) 1995 Wiley-Liss, Inc.