RESUMO
Activation of the ras family gene has been implicated in colorectal tumorigenesis, K-ras being the most frequently altered gene. The frequency of K-ras codon 12, 13 and 61 point mutations in patients with colorectal neoplasias was examined. We employed a polymerase chain reaction-restriction fragment length polymorphism assay and single-strand conformational polymorphism to detect mutations. We found that point mutations at codons 12 and 13 were present in 53% and 39% of the tumors, respectively, but none at codon 61. These results agree with previous reports. Point mutations were more frequent in adenomas than in carcinomas, with villous adenomas presenting a higher incidence of mutations than other adenomas. The association between clinical and histopathological parameters was investigated. Our study is the beginning of a new research line in molecular epidemiology of colorectal cancer and is the first to be carried out in one part of the Mexican population.