THE TYPE OF K-RAS MUTATION DETERMINES PROGNOSIS IN COLORECTAL-CANCER

BACKGROUND: Mutations involving the oncogene K-ras in colorectal cance r may be related to tumor aggressiveness. However, the value of K-ras gene determination as a prognostic marker has not been clearly establi shed. PATIENTS AND METHODS: The results from 98 patients recruited in a prospective study analyzing the effect of a K-ras mutation as a prog nostic factor in colorectal cancer are reported. RESULTS: Disease-free (P = 0.02) and overall survival (P = 0.03) were significantly reduced for patients harboring a K-ras mutation. Two specific mutations demon strated a significantly increased risk of disease recurrence, namely, 12-TGT (P = 0.04) and 13-GAC substitutions (P = 0.002). Patients with either of these substitutions had a 2-year disease-free survival rate of 37% compared with that of 67% for the group of patients harboring a ny other mutation type or a wild-type status (P = 0.01). CONCLUSIONS: The results herein presented suggest that K-ras acts as a prognostic f actor in colorectal cancer and that this effect is probably related to a limited number of defined mutations. (C) 1998 by Excerpta Medica, I nc.