THE STATUS OF THE GENE K-RAS IS AN INDEPENDENT PROGNOSTIC CRITERION IN PATIENTS WITH COLORECTAL CANCER

Actuality. One of the major somatic mutations found in colon tumors is the mutation in K-RAS gene which is revealed with in 30% - 50% of cases. The mutation in the K-RAS gene can become a new prognostic factor in one and the same stage of a disease. Objective. The aim of the research is to investigate frequency of mutation in K-RAS gene in patients with colorectal cancer in the Republic of Tatarstan, and to assess its influence on prognosis and the course of the disease. Materials and methods. The research included 120 patients with a colorectal cancer who received the combined treatment in Republican Clinical Oncology Dispensary of the Republic of Tatarstan. Genetic analysis of postoperative specimens for the presence of mutation in K-RAS gene was perfoemed. Results of own researches. Of 120 patients 35 (26.7%) were revealed K-RAS gene mutation , 85 patients having a wild-type of of K-RAS gene. In addition 25 mutations were found in 12-th and 13-th codones, 7 mutations were in 61-st codon and 3 were in the 146-th codon. Results of a research showed that the mutant type of a K-RAS gene is revealed more often in Russian population (38.9%) than in Tatar population (in 21.2%) (р =0.045). The mutation in K-RAS gene is more prevalent in women than in men (37.7% and 20.3% correspondingly). The existing relationship is of significance (р =0.045). Colon tumors with a mutant K-RAS gene are more prone to lymphogenous metastasizing (in 54.2%), than tumors with wild-type (45.8%), that indirectly shows more aggressive course of tumoral process in case of mutant type of a gene (р = 0.004). Patients with mutant type of gene have remote synchronous metastasis more often (63.6%), than patients with wild-type (36.4%). This dependence is statistically significant (р =0.0001). Annual survival rate of patients with wild-type of K-RAS gene was 96.5%, with mutant type of a gene was 88.6% (р =0.0012). Conclusion. Thus, the tumor with mutant type of K-RAS gene is characterized by aggressive course and high potential to metastasizing. The gene mutation in a tumor can be an independent significant prognostic sign for an assessment of the course and outcome of the disease.

colorectal cancer, mutations in K-RAS, a predictive criterion