Abstract

The mutations of K-ras oncogenes have been detected in about 20~30% of non-small cell lung cancer(NSCLC). In some reports K-ras activations are associated with smoking and poor prognosis in NSCLC patients who undergo curative resection. The ras oncogenes are usually activated by point mutations. The development of polymerase chain reaction-single strand conformation polymorphism(PCR-SSCP) enables us to detect the subtle nucleotide changes such as point mutations. In SSCP the electrophoretic mobility of single strand nucleotide de- pends on not only its size but also its conformation determined by DNA sequences. We analysed genomic DNAs of 41 human NSCLC obtained by thoracotomy using PCR-SSCP of K- ras codon 12, 13 and K-ras codon 61, and compared the results with clinical informations. The electrophoretic mobility changes were found in 10 of 41 NSCLCs(24.4%) in K-ras codon 12, 13. Those changes were found in six of 25 squamous cell carcinomas(24% ) and four of 16 adenocarcinomas(25%). But no change was found in K-ras codon 61. Comparisans of clinical parameters including age, sex, stage, smoking, and survival showedno significant differences between two groups with or without K-ras mutation. These results suggest that the mutation of K-ras oncogene may play an important role in the pathogenesis of some group of NSCLC though the clinical significances of these molecular events are open to further investigations.

• Keywords: Mutation, K-ras, Non-small cell lung cancer, PCR-SSCP