The association of steroid 5-alpha reductase type-II gene polymorphisms (A49T and V89L) with prostate cancer risk in African population: A systematic review and meta-analysis

African men are more predisposed to prostate cancer (PC). Genetic polymorphism is one of the risk factors that predispose men of African descent to PC. The steroid 5-alpha reductase type-II (SRD5A2), an androgen biosynthesis gene, encodes the SRD5A2 enzyme that converts testosterone to a more potent androgen, dihydrotestosterone (DHT), implicated in PC progression. Previous meta-analysis studies have investigated the association of PC risk across different races with polymorphisms in the SRD5A2 gene, including A49T and V89L. However, no meta-analysis study has been conducted exclusively on African populations. Hence, this meta-analysis study aimed to evaluate the association between SRD5A2 gene polymorphisms (A49T and V89L) and prostate cancer risk in the African population. We systematically performed a literature search of PubMed, Web of Science, ScienceDirect, and Scopus and conducted a meta-analysis of six (6) studies on the African population with 1,606 PC cases and 1,511 controls to evaluate the association of A49T and V89L polymorphisms of SRD5A2 with prostate cancer risk among Africans. The JASP software (version 0.18.3.0) was used to perform the meta-analysis. The odds ratios (OR) and confidence intervals (CIs) generated from the meta-analysis were used to evaluate the association using different genetic models. A significant between-study heterogeneity was observed across all genetic models, and therefore, we used the random effects (R.E) model to pool the results. Our study showed a positive association of PC risk with both polymorphisms examined, having an OR of 1.33 (95% CI:0.58-2.07, P-heterogeneity = 0.51) and an OR of 1.70 (95% CI:0.89-2.50, P-heterogeneity = 0.63) for V89L and A49T polymorphisms respectively, with a statistical significance of p<0.001. Our results revealed that the SRD5A2 polymorphisms, A49T and V89L, might increase the risk of PC among Africans. However, future meta-analysis studies, which will include a more significant number of studies on the African population with little or no publication bias, are recommended to validate our findings.