Identification of XRCC1 Arg399Gln and XRCC3 Thr241Met Polymorphisms in a Turkish Population and Their Association with the Risk of Chronic Lymphocytic Leukemia.

DNA repair systems are essential for cellular functions. Defects due to sequence variations in DNA repair genes can lead severe failure of cell functions and causing many cancer types including leukemia. The aim of this study was to investigate the relationship between XRCC1 Arg399Gln and XRCC3 Thr241Met polymorphisms and susceptibility to chronic lymphocytic leukemia (CLL) in Turkish patients. In addition, genotype distribution of these polymorphisms was compared with other populations. The frequencies of Arg399Gln and Thr241Met single nucleotide polymorphisms were studied in 25 CLL patients and 30 healthy individuals. Single nucleotide polymorphisms were genotyped by PCR-RFLP method. The genotype and allele frequencies of Arg399Gln and Thr241Met polymorphisms were not statistically different between the CLL patients and control group. The allelic frequency similarities were found between Turkish and Brazilian populations for Arg399Gln polymorphism. On the other hand, similarities were found between Turkish and other Caucasian populations for Thr241Met polymorphism. Marked differences were observed between American African versus Turkish and Chinese versus Turkish populations for Arg399Gln and Thr241Met polymorphisms respectively. These results indicate that Arg399Gln and Thr241Met polymorphisms were not associated with the development of CLL in Turkish population and ethnic differences is one of the most important factor for allele frequency differences.