GH1 T1663A polymorphism and cancer risk: a meta-analysis of case-control studies.

Many studies have demonstrated that the most common polymorphism (T1663A, rs2665802) in the promoter region of growth hormone 1 (GH1) gene might play an important role in cancer development and progression. This meta-analysis aims to investigate a more precise estimation of the relationship between GH1 T1663A polymorphism and cancer risk. We searched CISCOM, CINAHL, Web of Science, PubMed, Google Scholar, EBSCO, Cochrane Library, and CBM databases from inception through October 1st, 2013. Meta-analysis was performed using the STATA 12.0 software. Seven studies were included with a total of 4,018 cancer patients and 5,308 healthy controls. Our meta-analysis results revealed that GH1 T1663A polymorphism was associated with increased cancer risks. Subgroup analysis by cancer type showed significant associations between GH1 T1663A polymorphism and increased colorectal cancer risk, but there was no evidence of any association with breast cancer. Further subgroup analysis based on ethnicity indicated that GH1 T1663A polymorphism might increase cancer risks among Asian populations. However, no statistically significant association was found among Caucasian populations. Meta-regression analyses also suggested that cancer type and ethnicity may be the main sources of heterogeneity. No publication bias was detected in this meta-analysis. The present meta-analysis indicates that GH1 T1663A polymorphism may contribute to the risk of colorectal cancer, especially among Asian populations.