CYP24A1 and triple-negative breast carcinoma: Interestingly, triple-negative breast cancer patients have been shown to have lower serum vitamin D levels, and Cyp24A1 is known to catabolize both 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D. It is therefore tempting to speculate that higher levels of CYP24A1 might be linked to increased breast cancer risk [37].