Together, these results show that among the different breast cancer subtypes, PRL-induced acinar-like structures predominantly in the most differentiated HR+ breast cancer cells and promoted the elaboration of epithelial-like features (cell–cell clustering) in cells representing the mesenchymal claudin-low TNBC subtype implicating a morphogenic and differentiation role for PRL in breast cancer. This evidence concerns the gene PRL and breast carcinoma.