Association between MTHFR C677T, MTHFR A1298C and MS A2756G polymorphisms and risk of cervical intraepithelial neoplasia II/III and cervical cancer: A meta-analysis

Numerous case-control studies on the association between polymorphisms of key genes involved in methionine remethylation [methylenetetrahydrofolate reductase (MTHFR) and methionine synthase (MS)] and the susceptibility of cervical intraepithelial neoplasia (CIN) and cervical cancer have provided inconclusive results. The aim of the present meta-analysis was to determine the effects of two MTHFR (C677T and A1298C) and one MS gene polymorphism (A2756G) on the risk of CIN II/III or cervical cancer. Relevant data were retrieved following a systematic search in PubMed, Web of Science, MEDLINE and Wanfang Data up to November 2012. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were estimated from eligible studies by meta-analysis with subgroup analyses stratified by ethnicity. A total of 13 studies with 1,936 cases and 2,858 controls were included in the present metaanalysis. An increased risk of cervical cancer was found in Asian women with the MTHFR 677T allele (TT vs. CC: OR=1.41, 95% CI=1.071.86, P=0.01; TT vs. CC+CT: OR=1.38, 95% CI=1.08-1.75, P=0.008), while a decreased risk was observed in Caucasian women (TT vs. CC: OR=0.65, 95% CI=0.45-0.93, P=0.02; TT+CT vs. CC: OR=0.7, 95% CI=0.58-0.86, P=0.0005). No effects of MTHFR C677T polymorphism on CIN II/III risk and MTHFR A1298C or MS A2756G polymorphisms on cervical cancer risk were detected. The sensitivity analysis suggested stability of this meta-analysis and no publication bias was detected. The MTHFR 677T allele may enhance the risk of cervical cancer in the Asian female population and play a protective role in Caucasian females. However, limited association is suggested between MTHFR A1298C and MS A2756G polymorphisms with cervical tumorigenesis.