GENETIC INSTABILITY OF MICROSATELLITE SEQUENCES IN NONSMALL CELL LUNGCANCERS

To evaluate the frequency and pattern of microsatellite instability in NSCLCs, we examined 36 cases of resected NSCLC. The mean age of the p atients was 59.9 +/- 8.3 years. There were 19 cases of squamous cell c arcinoma, 15 of adenocarcinoma and two of large cell carcinoma. We obs erved microsatellite instability at one or more loci in 13 (36%) of 36 tumors analyzed, and this instability ranged from six tumors showing instability in only a single microsatellite to three tumors that had a lterations in three of four tested microsatellites. The microsatellite that showed instability most frequently in these tumors was D3S1340 ( 31%). Microsatellite instability was found in five (26%) of 19 squamou s cell carcinomas, six (40%) of 15 adenocarcinomas, and in both large cell carcinomas tested. We found microsatellite instability in four (2 4%) of 17 cancers at stage I, in one (17%) of six at stage II, in eigh t (73%) of eleven at stage IIIa, and in neither at stage IIIb. In conc lusion, microsatellite instability was noted in at least one third of non-small cell lung cancers, suggesting its possible role in cancer de velopment. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.