Overall, no significant association was found between RAD51 135G>C polymorphism and cancer susceptibility in any genetic model (dominant model: OR = 1.06, 95% CI = 0.96–1.08, P value of heterogeneity test [Ph]<0.001, I2 = 61.4%; recessive model: OR = 1.35, 95% CI = 0.89–2.03, Ph<0.001, I2 = 80.8%; additive model: OR = 1.46, 95% CI = 0.94–2.27, Ph<0.001, I2 = 72.8%). The gene discussed is RAD51; the disease is cancer.