CYP24A1 and hepatocellular carcinoma: Interestingly, Huh7.5 hepatoma cells also express CYP27B1 and 1,25-dihydroxyvitamin D3 24-hydroxylase (CYP24A1), which converts vitamin D3 to calcitriol, afterwards to calcitroic acid, indicating that hepatocytes comprise the entire apparatus for vitamin D metabolism and activity.