In the current study, a total of five case–control studies with 1,141 cases and 1,069 controls were included in the meta-analysis [13, 19–23], and the association between MMP-1-1607 1G/2G, MMP-2-1306 C/T, and MMP-9-1562 C/T polymorphisms and bladder cancer risk was explored. The gene discussed is MMP9; the disease is urinary bladder cancer.