YAP1 and breast carcinoma: Together, our results revealed that loss of PRLR expression in HR + MCF7 cells resulted in loss of cell-cell junctional complexes and a shift from luminal to basal-stem like cellular plasticity and that blocking YAP-CCN2 signaling with the chemical inhibitor VPF reestablished proper intercellular junctional adherence and luminal differentiation phenotype in breast cancer cells deficient in PRLR expression.