Diet folate, DNA methylation and genetic polymorphisms of MTHFR C677T in association with the prognosis of esophageal squamous cell carcinoma

BACKGROUND: Folic acid may affect the development of human cancers. However, few studies have evaluated the consumption of diet folate in the prognosis of patients with esophageal squamous cell carcinoma (ESCC). METHODS: One hundred and twenty five ESCC patients underwent esophagectomy between January 2005 and March 2006 in the Yangzhong People's Hospital were recruited and followed up. The effects of diet folate, aberrant DNA methylation of selected genes and methylenetetrahydrofolate reductase (MTHFR) C677T genetic polymorphisms on the prognosis of ESCC were evaluated by using Cox proportional hazard regression models. RESULTS: Our analysis showed an inverse association between diet folate intake and the risk of death after esophagectomy. The median survival time was 3.06 years for low or moderate folate consumption and over 4.59 years for high folate consumption. After adjusting for potential confounders, the hazard ratios (95% confidence interval) [HRs (95% CI)] were 0.72 (0.36-1.46) for moderate and 0.39 (0.20-0.78) for high folate intake, respectively (P for trend = 0.007). This preventive effect was more evident in patients carrying MTHFR 677CC genotype. No significant relation was observed between aberrant DNA methylation of P16, MGMT and hMLH1 gene, as well as MTHFR C677T genetic polymorphisms and the prognosis of ESCC. CONCLUSIONS: Our research indicated that diet folate intake may have benefits on the prognosis of ESCC after esophagectomy. From a practical viewpoint, the findings of our study help to establish practical intervention and surveillance strategies for managements of ESCC patients and can finally decrease the disease burden.