PRLR and breast cancer: We found that suppressing PRLR expression in the luminal HR+ MCF-7 breast cancer cells caused loss of their luminal (ER and CK18 markers expression) phenotype but enhanced their basal (CK5/6 marker expression) and mesenchymal/stemness (vimentin and CD44 markers expression) phenocopying human basal-like breast cancers43.