With regard to MMP-1-1607 1G/2G polymorphism, significant association was found with bladder cancer risk only under recessive model (2G2G vs. 1G2G/1G1G: OR = 1.44, 95 % CI = 1.05–1.97, P = 0.022, Fig. 1a), and as to MMP-2-1306 C/T polymorphism, significant association was found with bladder cancer risk only under homozygote model (TT vs. CC: OR = 2.10, 95 % CI = 1.38–3.10, P = 0, Fig. 1b), but we did not find any associations between MMP-9-1562 C/T polymorphism and bladder cancer risk (which only show homozygote model (TT vs. CC) in Fig. 1c). Here, MMP9 is linked to urinary bladder cancer.