MTHFR C677T polymorphism and risk of esophageal cancer: An updated meta-analysis

Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme involved in folate/homocysteine metabolism. A polymorphism C677T has been reported to be linked with risk of several diseases/disorders like birth defects, metabolic and psychiatric disorders and different cancers. The association between esophageal cancer and MTHFR gene C677T polymorphism has been investigated in several case-control studies, which rendered contradictory results. To shed light on association between MTHFR C677T polymorphism and risk of esophageal cancer, a meta-analysis of published case control association studies was conducted. Four electronic databases: PubMed, Google Scholars, Elsevier and Springer Link were searched up to August 2016. All statistical analyses were performed using MetaAnalyst and Mix (version 1.7). Odds ratios (ORs) with their 95% confidence intervals (95% CIs) were calculated. Total twenty-nine studies with 6520 cases and 9192 controls were included in the present meta-analysis. The results of meta-analysis suggested that there were significant association between C677T polymorphism and esophageal cancer risk using overall comparisons in five genetic models (T vs. C: OR = 1.20, 95% CI = 1.1–1.27, p = <0.0001; TT + CT vs. CC: OR = 1.37, 95% CI = 1.14–1.62, p = 0.0004; TT vs. CC: OR = 1.43, 95% CI = 1.1–1.84, p = 0.005; CT vs. CC OR = 1.35, 95% CI = 1.15–1.58, p = 0.0002; TT vs. CT + CC: OR = 1.19, 95% CI = 0.99–1.42, p = 0.05). Publication bias was absent. Subgroup analysis based on ethnicity and source of controls were also performed. In conclusion, results of present meta-analysis showed significant association between MTHFR C677T polymorphism and esophageal cancer.