PDCD1 and breast cancer: We also found a negative correlation between the PD-1 rs2227982 polymorphism and the risk of gastrointestinal cancer (OR = 1.18, 95% CI = 1.04–1.34, p = 0.011, CT vs. CC; OR = 1.16 (95% CI = 1.03–1.30, p = 0.017, CT+TT vs. CC) and breast cancer risk (OR = 0.73, 95% CI = 0.59–0.90, p = 0.004, CT vs. CC; OR = 0.73, 95% CI = 0.57–0.93, p = 0.010, TT vs. CC; OR = 73, 95% CI = 0.60–0.89, p = 0.002, CT+TT vs. CC; OR = 0.85, 95% CI = 76–0.96, p = 0.010, T vs. C).