Association of DNMT3B -283 T > C and -579 G > T polymorphisms with decreased cancer risk: evidence from a meta-analysis.

Numerous studies have explored the association of polymorphisms in the DNA methyltransferase 3b (DNMT3B) gene with the risk of different types of cancer, but yielded controversial results. Therefore, we performed a meta-analysis to derive a more precise estimation of the association between three widely-studied DNMT3B polymorphisms and overall cancer susceptibility. Totally, 4 studies with 1234 cases and 1337 controls were eligible for DNMT3B -283 T > C (rs6087990), 19 studies with 5332 cases and 7407 controls for DNMT3B -149 C > T (rs2424913), and 14 studies with 3933 cases and 4436 controls for DNMT3B -579 G > T (rs1569686). Overall, DNMT3B -283 T > C was associated with a significantly reduced risk of overall cancer (T vs. C: OR = 0.84, 95% CI = 0.71-0.99, P = 0.039). Likewise, the association of DNMT3B -579 G > T with a decreased overall cancer risk was also observed (heterozygous: OR = 0.77, 95% CI = 0.65-0.91, P = 0.003 and dominant: OR = 0.80, 95% CI = 0.66-0.98, P = 0.029); in the subgroup analysis, the protective association was found for lung and colorectal cancer, but not for head and neck cancer. Finally, the pooled analysis showed no significant association between DNMT3B -149 C > T and overall cancer susceptibility, but stratification analysis indicated that this polymorphism decreased the risk of developing head and neck cancer (heterozygous: OR = 0.73, 95% CI = 0.59-0.90, P = 0.003 and dominant: OR = 0.76, 95% CI = 0.61-0.93, P = 0.009). In conclusion, our results suggested that DNMT3B -283 T > C and DNMT3B -579 G > T but DNMT3B -149 C > T might confer protection against overall cancer risk. In the future, large and well-designed case-control studies are needed to validate our findings.