Role of K-ras mutations in colorectal carcinoma.

In order to investigate whether two common types of colorectal cancer with different gross appearances share the same incidence of K-ras mutation, the occurrence of a point mutation in codon 12 or codon 13 of the K-ras oncogene was determined in 50 cases of colorectal carcinoma. The PCR technique was employed, followed by RFLP analysis and sequencing to identify specific point mutations. No correlation was found between the presence of a K-ras gene mutation and histological parameters. A strong association was found between K-ras mutations and the gross polypoid appearance of colorectal carcinoma (polypoid 73% versus ulcerative 8%). The results indicate a preferential association with the K-ras oncogene involved in polypoid type colorectal carcinoma.