A SINGLE NUCLEOTIDE POLYMORPHISM IN THE RAD51 GENE IN COLORECTAL CANCER
RAD51 is a key enzyme for homologous recombination and play an important role in the repair of DNA double strand breaks. Increased levels of RAD51 protein and increased numbers of cells with nuclear RAD51 foci were found in a wide variety of tumor cell. Therefore, genetic variability in the RAD51 gene may contribute to the appearance and/or progression of cancer. We investigated the distribution of genotypes and frequency of alleles of a single nucleotide polymorphism, a G to C substitution at position 135 in the 5' untranslated region of the RAD51 gene (the 135 G/C 5'UTR polymorphism) in colorectal cancer. Tumor tissues and distant mucosa samples were obtained from 52 patients. Blood samples from 80 sex and age matched healthy persons served as control. The 135 G/C 5'UTR polymorphism was determined by PCR-based MvaI restriction fragment length polymorphism. No differences between genotypes of the polymorphism in cancer tissue and distant mucosa were found. The distributions of the genotypes in cancer patients and controls differed significantly (p < 0.05) from those predicted by the Hardy — Weinberg distribution. There were no differences in the frequencies of the G and C alleles between both groups. Our results suggest that the 135 G/C 5'UTR polymorphism may not be associated with colorectal cancer but further research performed on larger population is needed to clarify this point.
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