Here, we could describe the CYP2W1 mRNA and protein levels of CYP2W1 in human fetal colon and in SI, and using the immunohistochemical analysis, show the regio-selective distribution of CYP2W1 in the crypt cells of embryonic human colon, reminiscent of the CYP2W1 expression in colon cancer cells [7]. Here, CYP2W1 is linked to malignant colon neoplasm.