The association between endothelial nitric oxide synthase (eNOS) polymorphisms (intron 4a/b, -786T > C and 894G > T) and cancer risk remains elusive. In addition, no studies focused on their associations with risk of breast cancer in Chinese Han population. Thus, a meta-analysis was conducted to determine the relationship between eNOS polymorphisms and cancer risk, and then a case-control study in Chinese Han population was performed to assess their associations with breast cancer susceptibility.
Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of association.
The pooled analysis indicated that eNOS intron 4a/b and -786T > C polymorphisms were significantly associated with an increased risk of overall cancer. In subgroup analyses based on cancer type, the significant association was found between eNOS intron 4a/b polymorphism and prostate cancer risk, between eNOS -786T > C polymorphism and risk of prostate, bladder and breast cancers, and between eNOS 894G > T polymorphism and breast cancer risk. In subgroup analyses based on ethnicity, eNOS intron 4a/b and -786T > C polymorphisms were associated with an increased risk of cancer in Caucasians. In consistent with our meta-analysis results, a case-control study in Chinese Han population showed significant associations of eNOS -786T > C and 894G > T polymorphisms with the increased risk of breast cancer. In addition, stratified analyses based on pathological type showed that eNOS 894G > T polymorphism was only associated with risk of infiltrative ductal carcinoma. Stratified analyses by tumor stage showed that eNOS -786T > C polymorphism was only associated with the risk of tumor stage III and IV.
Our meta-analysis and case-control study suggest that eNOS -786T > C and 894G > T polymorphisms are associated with the increased risk of breast cancer.
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All authors have declared no conflicts of interest.