We found that the polymorphism of RAD18 rs250403 was significantly correlated with differentiation grade (χ2 = 8.750, P = .003), lymph node metastasis (χ2 = 4.758, P = .029), and vascular involvement (χ2 = 4.082, P = .043), while RAD18 rs615967 was significantly correlated with tumor family history (χ2 = 6.012, P = .014), differentiation grade (χ2 = 11.435, P = .001), and lymph node metastasis (χ2 = 6.719, P = .010). Here, RAD18 is linked to neoplasm.