By using different strategies to functionally inhibit RA-RARα signaling in RA-sensitive breast cancer cells (T47D), we found that–concomitant with heritable epigenetic gene silencing of the downstream RARβ2 receptor and tumor suppressor–cells not only survive, but also proliferate significantly more in response to RA ([13] and Fig. 1A). This evidence concerns the gene RARA and breast carcinoma.