The study conducted in the Swedish population showed no effect of the selected polymorphism within CYP27B1 (rs4646537) on risk of cancer, as well as no effect of any SNP within the VDR, CYP24A1, RXRA (retinoid X receptor alpha), GC/VDBP, 7-dehydrocholesterol reductase (DHCR7), and CYP2R1 genes (112 SNPs in total) [93]. This evidence concerns the gene GC and cancer.