We further genotyped 296 SNPs in the same subjects (N = 761) in CYP2R1, CYP27A1, CYP27B1, CYP24A1, and VDR genes directly involved in vitamin D metabolism, with an objective to elucidate variants that may modulate vitamin D levels, thereby potentially explaining their associations with lung cancer. The gene discussed is CYP2R1; the disease is lung carcinoma.