When data were stratified by cancer types, we found that IL-10 −592C>A polymorphism was significantly associated with bladder cancer risk in CC versus AA (P = 0.002, OR 0.51, 95% CI 0.33–0.78), CA versus AA (P = 0.004, OR 0.64, 95% CI 0.48–0.87), CC versus CA+AA (P = 0.02, OR 0.62, 95% CI 0.41–0.93), CA versus CC+AA (P = 0.04, OR 0.74, 95% CI 0.56–0.99), AA versus CC+CA (P = 0.0004, OR 1.65, 95% CI 1.25–2.19), and C versus A (P = 0.00001, OR 0.66, 95% CI 0.54–0.82). Here, IL10 is linked to cancer.