[Association between genetic polymorphisms in folate metabolic enzyme genes and colorectal cancer: a nested case-control study]

To investigate the interrelationship of genetic polymorphisms in folate metabolic enzymes (MTHFRC677T, MTHFRA1298C, MTRA2756G and MTRRA66G) and their combinative effects with colorectal cancer (CRC).A nested case-control study was designed and carried out. 140 CRC patients and 343 control subjects were included in this study. Polymorphisms of folate metabolic enzyme genes were genotyped by PCR-restriction fragment length polymorphism method. Risk of CRC was estimated by unconditional logistic model, and P value for interaction was calculated by likelihood test.The allele of MTR2756G showed a positive association with CRC (OR = 2.04, 95% CI = 1.22 - 3.40). Those with MTHFR1298AA and MTR 2756AG/GG genotypes had an elevated risk with CRC (OR = 2.57, 95% CI, 1.42 -4.65), and their combinative effect showed a significant association with CRC (P = 0.04).MTR2756G allele may be a risk factor of CRC, and interaction may exsit between polymorphisms of MTHFRA1298C and MTRA2756G. Further studies with larger sample and in different ethnic groups are needed.