It was observed that CYP27B1 expression is inversely correlated with the progression of tumors of prostate, lung, parathyroid, colon and skin [52,53,54,55,56,57,58], suggesting that local production of 1,25(OH)2D3 in CYP27B1-expressed tissues could be crucial for cancer prevention. This evidence concerns the gene CYP27B1 and cancer.