Here we demonstrate that an expanded p63<sup>+</sup> and CK5<sup>+</sup> basal/progenitor cell population, induced by the concomitant activation of oncogenic Kras(G12D) and androgen receptor (AR) signaling, underwent cell differentiation in vivo The differentiation process led to suppression of p63-expressing cells with a decreased number of CK5<sup>+</sup> basal cells but an increase of CK8<sup>+</sup> luminal tumorigenic cells and revealed a hierarchal lineage pattern consisting of p63<sup>+</sup>/CK5<sup>+</sup> progenitor, CK5<sup>+</sup>/CK8<sup>+</sup> transitional progenitor, and CK8<sup>+</sup> differentiated luminal cells.