RARA and ductal breast carcinoma in situ: HME1“DCIS-precursor” cell lines when grown in 3D basement membrane culture evade the growth inhibitory and pro-apoptotic effects regulated by physiological Retinoic Acid (RA) via the RA receptor alpha (RARA) transcriptional function, which is indispensable for lumen formation [7,9,10,11,12], but retain the RARA function that enables the physiological RA induction of AKT signaling by the phosphatidylinositol-3 kinase catalytic (PI3KCA) subunit ([13] and references within).