CD44 and neoplasm: Among epithelial populations, we identified tumor cells (expressing Cd44, Ccnd1, Plau, Krt7), luminal alveolar (AV) cells (expressing Kit, Ehf, Csn3, Ltf), luminal hormone-sensing (HS) cells (expressing Prlr, Esr1, Pgr), and myoepithelial cells (expressing Myh11, Mylk, Myome1).