[Activation of K-ras and c-erbB-2 protooncogenes in human colonic adenocarcinomas]

Although data on genetic alterations leading to development of colorectal cancer are abundant, no specific genetic alteration has been demonstrated for each class of tumor. The colorectal cancer phenotype is originated from an accumulation of different genetic alterations. The nature of these alterations, their order of appearance, and their associations vary greatly from one tumor to another, suggesting that the concept of a unique model of carcinogenesis is not applicable to these tumors. The aim of the present work was to study the association between K-ras and c-erbB-2 mutations and different clinicopathological variables in fifty-four samples from adenocarcinomas of the colon. The detection of K-ras activation was performed by specific enriched PCR. The genomic differential polymerase chain reaction with the single copy reference gene was employed for the detection of c-erbB-2 gene amplification. K-ras mutations were detected in 16 cases (29.63%) and c-erbB-2 amplifications in 1 sample (1.85%). Statistical analysis showed a significant association between K-ras codon 12 mutation frequency and Duke's stage B (p < 0.05). On the other hand, there was no association in relation to the other studied parameters. These results could indicate the occurrence of K-ras activation in early stages of the disease.