INCREASED PREVALENCE OF K-RAS ONCOGENE MUTATIONS IN LUNG ADENOCARCINOMA

Reported estimates of ras mutation prevalence in lung adenocarcinoma o f 15-24% may be underestimates because of the insensitivity of the ass ays used. We have devised a rapid, non-radioactive assay for ras mutat ions, which detects 1 mutant allele/10(3) normal alleles and hal e use d it to study DNA isolated from 53 lung tumor samples (including 28 ad enocarcinomas) previously analyzed by PCR/allele specific oligonucleot ide hybridization, which is less sensitive. We detected mutations in 1 3 of 28 samples, including 7 not detected by PCR/allele specific oligo nucleotide hybridization. We also found ras mutations in 14 of 25 prev iously unstudied samples (56%). Our results indicate that the prevalen ce of K-ras codon 12 mutations in lung adenocarcinoma is higher than p reviously reported; thus, ras mutations may be more clinically useful as molecular markers for lung cancer than has been appreciated.