Of association between survivin 231G.C polymorphism and esophageal cancer risk may be due to a lack of a sufficient number of eligible studies andthe influence of different genetic and environmental factors. More research is needed to determine the association between survivin gene polymorphisms and esophageal cancer risk. Further stratified analysis by ethnicity and country, the results identified that survivin 231G.C polymorphism as a risk factor for GIT cancer among both Asian and Caucasian populations, and was also associated with increased risk among Chinese, Greek and Indian populations, but not in Brazilian populations. The reasons for the diverse results might include differences in genetic backgrounds and environments, different matching criteria and selection biases. In interpreting our results of the current meta-analysis, some limitations need to be addressed. Firstly, the sample size is still relatively small and may not provide sufficient statistical power to estimate the correlation between survivin 231G.C polymorphism and GIT cancer risk. Secondly, the selection bias may exist because of the differences in source of controls or detection samples. Thirdly, our meta-analysis was based on unadjusted ORs estimates because not all published presented adjusted ORs and if they did, the ORs were not adjusted by the same potential confounders, such as ethnicity, age, gender, geographic distribution, etc. Nevertheless, it is well acknowledged that many other factors, such as gene-gene or gene-environment interaction may affect the risk of GIT cancer. Furthermore, the present metaanalysis also includes most of the studies from Asian populations, which may not provide strong evidence of Ergocalciferol heterogeneity by ethnicity. Finally, although all cases and controls of each study were well defined with similar inclusion criteria, there may be other potential GSK -3203591 factors that were not taken into account that may have influenced our results. In spite of these limitations, our meta-analysis still has some advantages. The specific aim of this study is to update the previous meta-analyses and focus on the correlation between survivin 231G.C polymorphism and GIT cancer risk. Unlike previous meta-analyses, we find that survivin 31G.C polymorphism is associated with increased risk of gastric and colorectal cancers. It is worthwhile to mention that we have established an effective and efficient searching strategy based on computer-assisted program and manual search to find all possible and eligible studies. Through this search strategy, the quality of studies included in this meta-analysis satisfied our selection criteria. Furthermore, explicit methods for study selection, data extraction, and data analysis were well 23977191 designed before initiating the calculations. Last but not least, there were no evidences of publication bias in this metaanalysis and the sensitivity analysis indicated that the results are statistically robust. In summary, this meta-analysis suggests that survivin 31G.C polymorphism may be a risk factor for developing GIT cancer, especially among gastric and colorectal cancers. However, further studies are necessary in order to warrant and validate the associations between survivin gene polymorphisms, other gene polymorphisms and GIT cancer risk.Supporting InformationSupplement S1 PRISMA Checklist.(DOC)Supplement S2 Modified STROBE quality score sys-tems. (DOC)AcknowledgmentsWe would like to acknowledge the helpful comments on this paper rece.Of association between survivin 231G.C polymorphism and esophageal cancer risk may be due to a lack of a sufficient number of eligible studies andthe influence of different genetic and environmental factors. More research is needed to determine the association between survivin gene polymorphisms and esophageal cancer risk. Further stratified analysis by ethnicity and country, the results identified that survivin 231G.C polymorphism as a risk factor for GIT cancer among both Asian and Caucasian populations, and was also associated with increased risk among Chinese, Greek and Indian populations, but not in Brazilian populations. The reasons for the diverse results might include differences in genetic backgrounds and environments, different matching criteria and selection biases. In interpreting our results of the current meta-analysis, some limitations need to be addressed. Firstly, the sample size is still relatively small and may not provide sufficient statistical power to estimate the correlation between survivin 231G.C polymorphism and GIT cancer risk. Secondly, the selection bias may exist because of the differences in source of controls or detection samples. Thirdly, our meta-analysis was based on unadjusted ORs estimates because not all published presented adjusted ORs and if they did, the ORs were not adjusted by the same potential confounders, such as ethnicity, age, gender, geographic distribution, etc. Nevertheless, it is well acknowledged that many other factors, such as gene-gene or gene-environment interaction may affect the risk of GIT cancer. Furthermore, the present metaanalysis also includes most of the studies from Asian populations, which may not provide strong evidence of heterogeneity by ethnicity. Finally, although all cases and controls of each study were well defined with similar inclusion criteria, there may be other potential factors that were not taken into account that may have influenced our results. In spite of these limitations, our meta-analysis still has some advantages. The specific aim of this study is to update the previous meta-analyses and focus on the correlation between survivin 231G.C polymorphism and GIT cancer risk. Unlike previous meta-analyses, we find that survivin 31G.C polymorphism is associated with increased risk of gastric and colorectal cancers. It is worthwhile to mention that we have established an effective and efficient searching strategy based on computer-assisted program and manual search to find all possible and eligible studies. Through this search strategy, the quality of studies included in this meta-analysis satisfied our selection criteria. Furthermore, explicit methods for study selection, data extraction, and data analysis were well 23977191 designed before initiating the calculations. Last but not least, there were no evidences of publication bias in this metaanalysis and the sensitivity analysis indicated that the results are statistically robust. In summary, this meta-analysis suggests that survivin 31G.C polymorphism may be a risk factor for developing GIT cancer, especially among gastric and colorectal cancers. However, further studies are necessary in order to warrant and validate the associations between survivin gene polymorphisms, other gene polymorphisms and GIT cancer risk.Supporting InformationSupplement S1 PRISMA Checklist.(DOC)Supplement S2 Modified STROBE quality score sys-tems. (DOC)AcknowledgmentsWe would like to acknowledge the helpful comments on this paper rece.
