CDKN2A and urinary bladder carcinoma: Subgroup analysis based on geographic area showed a subtle distinction between p16 expression and OS in patients with bladder cancer in Asia (HR = 1.61, 95% CI = 0.97~2.66, and P = 0.065; I2 = 0%, P = 0.703) and Europe (HR = 2.54, 95% CI = 1.05~6.15, and P = 0.039; I2 = 27.0%, P = 0.250).