VALIDATION OF THE POINT-EXACCT METHOD IN NONSMALL CELL LUNG CARCINOMAS

K-ras point mutations are often detected in part of the lung carcinoma s. For the validation of a highly sensitive and rapid assay for known point mutations, Point-EXACCT (Biochim Biophys Acta 1998; 1379:42-52), we analyzed 89 non-small cell lung carcinomas and compared the result s with two sequencing methods. No point mutations were found with doub le-stranded sequencing. Single-stranded sequencing detected six patien ts positive for K-ms codon 12. When Point-EXACCT was used, K-ras codon 12 mutations were detected in 8 of 52 patients with squamous cell car cinomas, 10 of 29 patients with adenocarcinomas, and 3 of 8 patients w ith large cell carcinomas. The finding of K-rns mutations in squamous cell carcinomas is explained by the high sensitivity of the method. Th erefore, Point-EXACCT may be applicable to detection of those alterati ons occurring at a low frequency among an excess of cells with wild-ty pe DNA.