Association of Three Single Nucleotide Polymorphisms in MTR and MTRR Genes with Lung Cancer in a Turkish Population

Aims: Folate metabolism plays a critical role in DNA methylation and synthesis. Polymorphisms in folate metabolism may affect enzyme activities and thereby affect the cancer risk. Methionine synthase (MTR) and methionine synthase reductase (MTRR) are critical enzymes for the folate cycle. In this study, possible associations between genetic variabilities in MTR and MTRR and susceptibility to lung cancer (LC) were investigated in a Turkish population. Methods: A case-control study with 193 LC cases and 199 noncancerous controls was conducted. DNA was extracted from leukocytes using the high pure polymerase chain reaction (PCR) template preparation kit. The MTR 2756A>G (rs1805087), MTRR 524 C>T (rs1532268), and MTRR 66A>G (rs1801394) genotypes were determined using PCR-restriction fragment length polymorphism (PCR-RFLP) assays. The genotype and haplotype analyses of these polymorphisms were performed using SPSS 21 and Haploview 4.2, respectively. Results: An association between the MTRR A66G polymorphism and LC (p = 0.042) was found. In addition, this allele was observed more frequently in smokers compared to nonsmokers (p = 0.030). In contrast, the distribution of the MTR 2756A>G and the MTRR 524 C>T allele frequencies were similar in the subject cases and controls. Conclusions: In conclusion, the present study suggests an association between the MTRR 66A>G gene polymorphisms and LC risk in a Turkish population.