While the MR-inducible cell line used was a breast cancer cell line (MCF-7), this choice of parent cell line partly reflects the paucity of viable non-malignant cell models in which to test our hypothesis of a functional relationship between MR and RAR signalling in the normal breast and, moreover, we would argue that given the low basal MR level of the parent, by restoring MR expression in these cells, the MR-induced state more closely resembles the normal breast or is at least closer to the good prognosis subset of breast cancer suggested by our data. This evidence concerns the gene RARA and breast carcinoma.