RET and medullary thyroid gland carcinoma: An increased risk association was identified for NAT2Y94Y SNP (OR 1.62, 95% CI 1.17‐2.25, P = .004) and CDKN2A3′UTR SNP (OR 1.89, 95% CI 1.19‐2.98, P = .006) with sporadic MTC and RET S904S with hereditary MTC (OR 2.82, 95% CI 1.64‐4.86, P < .001).