Common polymorphisms in methylenetetrahydrofolate reductase gene are associated with risks of cervical intraepithelial neoplasia and cervical cancer in women with low serum folate and vitamin B12

We evaluated associations between folate, vitamin B12, and the methylenetetrahydrofolate reductase (MTHFR) gene, and risk of cervical intraepithelial neoplasia (CIN) and cervical cancer. This multicenter case-control study enrolled 927 Korean women (440 controls, 165 patients with CIN 1, 167 patients with CIN 2/3, and 155 patients with cervical cancer, aged 20-75 years). Patients with cervical cancer had significantly lower median serum folate and vitamin B12 concentrations vs. controls. Higher serum folate was significantly associated with lower cervical cancer risk (p for linear trend = 0.0058) with a trend for a lower CIN risk after multivariate adjustment. Low folate and the MTHFR 677 C > T variant were associated with a higher risk for CIN2/3 and cervical cancer vs. wild-type or heterozygous genotypes with high folate [OR, 2.39 (1.18-4.85) and 3.19 (1.43-7.13)]. Low vitamin B12 and the MTHFR 677 C > T variant also were associated with a higher risk for CIN 2/3 and cervical cancers [OR, 2.52 (1.17-5.42) and 2.40 (1-5.73)] vs. wild-type or heterozygous status with high vitamin levels. Serum folate concentration is inversely associated with the risk of cervical cancer, and the MTHFR variant genotype may increase CIN and cervical cancer risk in women with low folate or vitamin B12 status.