Polymorphism within the distal RAD51 gene promoter is associated with colorectal cancer in a Polish population.

BACKGROUND Colorectal cancer (CRC) is one of the most common cancers in developed countries. Annually, over one million of new cases in the world are recorded. Majority of CRCs occur sporadically with dominant phenotype of chromosomal instability (CIN). Permanent exposure to DNA damaging agents such as ionizing radiation result in DNA double-stranded breaks, which create favorable conditions for chromosomal aberration to arise. Homologous recombination repair (HRR) is the leading process engaged in maintaining of the genome integrity. RAD51 protein was recognized as crucial in HRR. Single nucleotide polymorphisms are the primary source of genetic variation which presence in the RAD51 promoter region can affect on its expression and consequently modulate HR efficiency. OBJECTIVES The aim of this study was to analyze the distribution of genotypes and allele frequencies of -4791A/T and -4601A/G RAD51 gene polymorphisms, followed by an assessment of their relationship with the risk of CRC. MATERIAL AND METHODS The study included 115 patients with confirmed CRC. Control group was consisted of 118 cancer-free individuals with a negative family history. The genotypes were identified by PCR-RFLP method. CONCLUSION This study revealed statistically significant association between appearance of G/A genotype in position -4601 of RAD51 gene and CRC risk.