RXRG and breast cancer: Steroid-Receptors, Heterodimeric-Receptors and the Lipid-sensors, Retinoid-X-Receptors (NR2B1/RXRα, NR2B2/RXRβ, NR2B3/RXRγ) are excluded from our analysis given the wealth of data on their therapeutic significance in breast-cancer [4, 5].