Immunohistochemical analysis of selected markers. A, D): Overexpression of myosin VI (MYO6) in tumoral (t) and PIN glands, as compared to normal (n) glands (inset, higher magnification showing a luminal reinforcement). B, E): Overexpression of multidrug resistance-associated protein 4 (ABCC4) in tumoral and PIN glands (inset in B, higher magnification showing a membrane staining pattern). C) Ephrin type-A receptor 2 precursor (EPHA2) was not detected in tumoral glands, while it was expressed in a subpopulation of basal cells in normal glands (n). F) Higher magnification showing a cytoplasmic and membrane staining pattern of EPHA2. Bars correspond to 100 μm.