The G894t, T-786c and 4b/a polymorphisms in Enos gene and cancer risk: a meta-analysis

Published results on association between eNOS polymorphisms and cancer risk are conflicting. We aimed to investigate the association and give an overall understanding of possible risk role of eNOS.

We searched PubMed and EMbase databases. The pooled ORs and 95% CIs for the association between eNOS polymorphisms and cancer risk was estimated using fixed- or random- effect model. Subgroup and sensitivity analyses were employed for further analysis.

The Overall results showed no significant association of G894T polymorphism with cancer susceptibility (T vs. G: OR 1.02, 95% CI 0.97 to 1.07; TT+GT vs. GG: OR 1.02, 95% CI 0.96 to 1.09; TT vs. GT+GG: OR 1.05, 95% CI 0.93 to 1.17). For the T-786C polymorphism, pooled OR under recessive model suggested that CC genotype was significantly associated with increased cancer risk (CC vs. TC+TT: OR 1.31, 95% CI 1.09 to 1.57). For the 4b/a polymorphism, pooled OR for recessive model suggested positive result of 4a/4a genotype (aa vs. ba+bb: OR 1.64, 95% CI 1.11 to 2.43). In subgroup analysis by ethnicity, significant association was found in Caucasians in recessive model but not in Asians for T-786C and 4b/a, respectively. In subgroup analysis by cancer types, significant result was obtained for breast cancer in recessive model for the T-786C polymorphism.

The eNOS G894T polymorphism may not be a major risk factor for most types of cancers. The CC of T-786C polymorphism and 4a/4a of 4b/a polymorphism are associated with cancer risk, especially in Caucasians. There is significant association between T786C polymorphism and breast cancer risk. More data are needed to verify these results.