Detection of k-ras mutations in nonsmall cell lung-carcinoma.

Forty-five non-small cell lung cancers (NSCLC) were examined for the presence of K-ras mutations in codon 12 using RFLP (restriction fragment length polymorphism) and ARMS (amplification refractory mutation system) assays. The RFLP analysis consisted of a PCR and subsequent digestion of the product with BstNI. Three adenocarcinomas and one adenosquamous carcinoma were shown to have mutations at codon 12. All of these samples were also examined using the ARMS assay for mutations at codon 12 and second base G to A transitions at codon 13 of the K-ras gene. The same four samples were confirmed to have a single base change in codon 12. No G to A transitions were found at codon 13. The four mutations were: one G to C transversion, one G to A transition and two G to T transversions. All mutations occurred at the second position of codon 12 as shown by the ARMS assay. Both of these techniques are rapid and reproducible for the identification of mutations in the K-ras gene and have potential for use in cancer diagnosis.