CYP27A1 and breast cancer: Most of these enzymes are absent from the BC cell lines (supplemental Table S2) except CYP27A1 which is well expressed in MDA-MB468 suggesting in this case that polar compounds that are observed on the bottom of the TLC autoradiogram of cell culture media extracts from MDA-468 (Fig. 3A, C) are likely to be C27 derivatives of OCDO and CT.