Prognostic value of TP53 and K-ras-2 mutational analysis in stage III carcinoma of the colon

BACKGROUND: Genetic mutations involving oncogenes and tumor-suppressor genes occur in carcinogenesis, and may effect biologic behavior of neoplasms. In this study, we analyzed the prognostic value of mutational analysis in colon carcinoma. PATIENTS AND METHODS: Archival pathology specimens from 70 consecutive patients, resected for stage III colon carcinoma, were analyzed for point mutations by amplification and direct sequencing of exons from the K-ras-2 and the TP53 genes (topographic genotyping). Mutations were compared with adverse histopathologic features (poor differentiation, vascular and lymphatic invasion, mucin production) as prognostic markers. RESULTS: Five- year survival was 75% in patients with nonmutated lesions, significantly lower (21%) with TP53 mutations (P = 0.01), and intermediate with K-ras-2 only (45%) or both K-ras-2 and TP53 mutations (36%). A TP53 mutation carried the highest relative risk of death (2.39; 95% confidence interval, 1.29 to 4.42; P = 0.006). There was an additive effect on the risk of death between TP53 mutations and adverse histopathologic features. CONCLUSIONS: The information derived from mutational analysis is creating new prognostic variables that may play a role in the choice of therapy for colorectal carcinoma.