Our observation is consistent with previous studies that noted 1,25(OH)2D3-mediated, duodenal CYP3A4 regulation in human colon cancer cells lines (Caco-2, LS180), and undifferentiated human colonoids (8–10) as well as induction of the CYP3A4 homologs Cyp3a1 or Cyp3a11 in vitamin D deficient rats, mouse intestinal segments, and in mouse duodenal enteroids (3, 7, 35). Here, CYP3A4 is linked to malignant colon neoplasm.