Involvement of K-RAS mutations and amino acid substitutions in the survival of metastatic colorectal cancer patients

The efficacy of epidermal growth factor-targeting therapies has been found to be limited in tumors with the wild-type K-RAS gene, suggesting a predictive value of K-RAS gene analysis in tumoral response. However, the prognostic value of K-RAS is controversial. This study included patients diagnosed with metastatic colorectal cancer. The presence of K-RAS mutations was analyzed, and the tumors positive for a K-RAS mutation were further analyzed to identify the mutation type. Similarly, the following clinical and pathological variables were also collected. The study was composed of 53.3 % of patients with wild-type K-RAS and 46.7 % of patients with mutated K-RAS (mutated codon 12 was the most frequent). With a mean follow-up of 15 months (range, 1–45), the median survival of patients with wild-type K-RAS was 31.6 months. The median survival was 24.8 months for patients with K-RAS mutated in codon 12 and 17.8 months for patients with mutated codon 13 ( p = 0.37). In a univariate analysis, K-RAS was associated with stage IV at diagnosis ( p