膀胱癌的病因尚不清楚。本研究调查了基因多态性，特别是甲基四氢叶酸还原酶基因(MTHFR)对膀胱癌易感性的影响，重点关注rs1801133单核苷酸多态性(SNP)。遵循PRISMA指南并在PROSPERO（CRD42023423064）登记后，对MTHFR基因文献进行系统回顾，进行了一项荟萃分析。共纳入了七项研究，显示出MTHFR C677T（rs1801133）多态性与膀胱癌易感性之间存在显著相关性。携带T等位基因或TT基因型的个体容易患膀胱癌。在亚洲人群中，总体分析显示T等位基因与C等位基因的比值比（OR）为1.15（95% CI 1.03-1.30；p值=0.03），TT基因型与TC+CC基因型的比值比为1.34（95% CI 1.04-1.72；p值=0.02）。然而，CC基因型与膀胱癌之间没有显著相关性。值得注意的是，表观遗传学发现显示低敏感性但高特异性，表示可靠地确认了与膀胱癌相关的一些表观遗传因素，但也有可能忽视了一些与膀胱癌相关的表观遗传因素。总之，MTHFR的T等位基因和TT基因型与亚洲人群中膀胱癌风险增加相关。这些对影响膀胱癌易感性的遗传因素的认识可以为有针对性的预防和治疗策略提供参考。进一步的研究有必要验证和扩展这些发现。

The etiology of bladder cancer remains unclear. This study investigates the impact of gene polymorphisms, particularly methylenetetrahydrofolate reductase gene (MTHFR), on bladder cancer susceptibility, focusing on the rs1801133 single-nucleotide polymorphism (SNP). A meta-analysis was conducted after systematically reviewing the MTHFR gene literature, adhering to PRISMA guidelines and registering in PROSPERO (CRD42023423064). Seven studies were included, showing a significant association between the MTHFR C677T (rs1801133) polymorphism and bladder cancer susceptibility. Individuals with the T-allele or TT genotype had a higher likelihood of bladder cancer. In the Asian population, the overall analysis revealed an odds ratio (OR) of 1.15 (95% CI 1.03-1.30; p-value = 0.03) for T-allele versus C-allele and an OR of 1.34 (95% CI 1.04-1.72; p-value = 0.02) for TT genotype versus TC+CC genotype. The CC genotype, however, showed no significant association with bladder cancer. Notably, epigenetic findings displayed low sensitivity but high specificity, indicating reliable identified associations while potentially overlooking some epigenetic factors related to bladder cancer. In conclusion, the MTHFR T-allele and TT genotype were associated with increased bladder cancer risk in the Asian population. These insights into genetic factors influencing bladder cancer susceptibility could inform targeted prevention and treatment strategies. Further research is warranted to validate and expand these findings.