PGR and malignant colon neoplasm: Vitamin D receptor expression is enhanced during early stages of colon cancer but, analogously to oestrogen and progesterone receptors in breast cancer, it is downregulated during late colon cancer progression (Sheinin et al, 2000; Cross et al, 2001), causing ligand unresponsiveness and, possibly, failure of therapy with vitamin D analogues (Figure 2).