CDKN2A and urinary bladder cancer: Subgroup analysis based on histopathological grade showed that heterogeneity decreased from G1-G2 (HR = 4.12, 95% CI = 2.48~6.83, and P < 0.001; I2 = 0%, P = 0.924), G1–G3 (HR = 1.44, 95% CI = 1.18~1.75, and P < 0.001; I2 = 11.9%, P = 0.323), and G2-G3 (HR = 1.37, 95% CI = 0.78~2.42, and P = 0.273; I2 = 0%, P = 0.802), indicating that the effects of p16 on RFS in patients with bladder cancer were closely associated with pathological grade.