COMT GENE POLYMORPHISM AND RADIATION REACTIONS OF NORMAL TISSUE IN BREAST CANCER PATIENTS

I.A. Zharikova, Yu.A. Ragulin, T.V. Kondrashova
Medical Radiological Research Center, Russian Federation, 249036, Kaluga region, Obninsk, Koroleva Str., 4

Introduction. The COMT gene encodes for a protein involved in deactivation of genotoxic estrogen species, and the protein product encoded by the L (low activity) allele is 3–5-fold less active than its counterpart encoded by the H (high activity) allele. The aim of the study. The study was designed to compare the severity of normal tissue reactions to radiation therapy in breast cancer patients with different genotypes at the polymorphic site COMT*H/L. Methods. The study group included 92 breast cancer patients, who received radiation therapy; total local doses were 50–60 Gy. Tissue reactions were classified as three groups, namely expressed, moderate, and no reaction. Genotypes at the polymorphic site were determined by PCR-RFLP technique. Results. It was found that individual ray reaction was associated with the L allele frequency: 0,46 in patients without ray reactions, 0,52 – in patients with moderate reactions, and 0,64 – in patients with expressed ray reactions of normal tissues (p
Keywords: 
breast cancer, radiation therapy, COMT gene, radiation reactions