Fig. 1

Effects of pregnancy on lesion histopathology. A Milk-associated protein (MAP) IHC staining of a number 4 mammary gland at day 3 postpartum from a 9-week-old dam. Inguinal region on the right-hand side, dorsal region on the left-hand side. Lesions identified and named by Lin et al. [18] to be characteristic of disease progression are circled in yellow and are shown at higher magnification below. Failed lobuloalveolar development (FLAD) is indistinguishable from hyperplasia. B Corresponding lesion IHC staining for PyMT protein. C Novel histopathological features seen in the immediate postpartum period, MAP IHC of a whole 2nd and 3rd mammary glands shown in the center panel and H&E at higher magnification of the circled features shown either side. D PyMT staining of metastases, E MAP staining of metastases