RXRA and breast carcinoma: Thus, in the current study, the growth-suppressive activity of RXR pan agonists (LGD1069 and LG100268) and an RXRα specific ligand (Ro25-7386) were investigated in normal human mammary epithelial cells (HMECs) and four breast cancer cell lines (MCF-7, T47D, MDA-MB-231 and MDA-MB-435) using an MTS assay.