As illustrated in Supplementary Fig. 9, loss of PRLR expression in luminal and epithelial breast cancer subtypes altered their differentiation status promoting the complex multifaceted tumorigenic features of breast cancer including stemness, tumor development, metastasis, and resistance to therapies and positions PRL/PRLR pathway as a differentiation therapeutic target in breast cancer. The gene discussed is PRLR; the disease is breast cancer.