Background: BCL-2 Associated X (BAX) is an important modulator of apoptosis. The associations between BAX gene polymorphism and cancer susceptibility and prognosis in different ethnic groups and types of cancer have yielded controversial results. To reconcile the results, a systematic review followed by meta-analysis was performed to assess the associations.
Methods: A systematic search of Medline database (PubMed), EMBASE, China Biology Medicine disc, China National Knowledge Infrastructure, Wanfang databases for publications on BAX polymorphisms, and susceptibility and prognosis was carried out until July 2017. Retrieved 14 articles met the inclusions. Summary odds ratios (ORs) and hazard ratios (HRs) with their 95% confidence intervals (CIs) were harnessed to determine the strength of correlation between BAX polymorphisms and cancer susceptibility and prognosis, which were combined using fixed- or random-effects models as appropriate.
Results: A total of 12 trials involving 3321 cases and 3209 controls were included in our pooled analysis regarding the polymorphisms and the susceptibility of cancers. Overall, results of the present meta-analysis demonstrated that there was no significant association between BAX polymorphisms and susceptibility of cancers (OR = 1.052, 95% CI: 0.827-1.339, P = .679, A vs G). Even in a stratified analysis by ethnicity and the sources of control groups, the results were consistent. Four retrospective studies of 549 cases qualified for meta-analysis were identified to set forth the associations of the polymorphisms with cancer prognosis. Our results suggested that BAX gene polymorphisms were significantly associated with unfavorable prognosis (HR = 1.735, 95% CI: 1.368-2.202, P = .000, GG vs GA/AA).
Conclusion: There is no significant association between BAX gene polymorphism and cancer susceptibility, but it probably contributes to increased adverse prognosis to cancer.