[Clinical-pathological features and gene profile in colorectal cancer]

Colorectal cancer is the third most frequent cancer in men and the second most frequent in women, with a worldwide incidence of approximately 1.2 million new cases per year. Our primary objective was to study the relationship between clinical and histological features of individuals with colorectal cancer and the mutational status of codons 12 and 13 of the KRAS gene (7 validated mutations), in order to find a histopathological marker to mutated tumors. The secondary objective was to determine how many patients had additional mutations in codons 15 and 61 of the KRAS gene, and codon 600 of the BRAF gene, which could modify the tumor phenotype. Sixty individuals with colorectal cancer (30 wild-type subjects and 30 with validated mutations in codons 12 and 13 of the KRAS gene) were selected. Exons 2 and 3 of the KRAS gene, and exon 15 of the BRAF gene were amplified and sequenced. The data collected were reviewed by a descriptive, univariate and/or multivariate analysis, as appropriate. In conclusion, no relation was found between clinical and histological features of individuals with colorectal cancer and their mutational status for codons 12 and 13 of the KRAS gene. This suggests that those easily available data do not allow predicting the response to anti-EGFR therapy. In patients with advanced colorectal adenocarcinomas and KRAS wild-type status, further study of codon 600 of the BRAF gene could be required.