The IL-17A rs2275913G>A polymorphism showed significant associations with cancer risk in all populations (for A versus G: OR = 1.28, 95% CI: 1.16–1.41, P < 0.001, I2 = 61.1%; for GA versus GG: OR = 1.12, 95% CI: 1.02–1.23, P = 0.015, I2 = 27.8%; for AA versus GG: OR = 1.71, 95% CI: 1.38–2.41, P < 0.001, I2 = 69.6%; for GA + AA versus GG: OR = 1.23, 95% CI: 1.13–1.34, P < 0.001, I2 = 6.4% (Figure 2); and for AA versus GG + GA: OR = 1.62, 95% CI: 1.27–2.07, P < 0.001, I2 = 81.4%). The gene discussed is IL17A; the disease is cancer.