Figure 4.

Immohistochemical features of the mammary tumors from cases 1 and 2. (A and C) p63 immunohistochemistry. Myoepithelial cells constituting the basal layer of neoplastic lobules were immunoreactive for p63 in both cases. Immunoreactive cells formed a discontinuous row of basally located cells (white arrows) and were rarely noted more superficially in the tumor (arrow, C). Hematoxylin counterstain; scale bar, 20 μm. (B and D) E-cadherin immunohistochemistry. Neoplastic cells exhibited strong positive membranous (and less prominent cytoplasmic) staining for E-cadherin in both cases. Hematoxylin counterstain; scale bar, 20 μm. (E and G) p53 immunohistochemistry. Scattered neoplastic cells exhibit strong positive nuclear expression of p53 in both cases. Hematoxylin counterstain; scale bar, 20 μm. (F and H) Ki67 immunohistochemistry. (F) Approximately 10% to 15% of neoplastic cells in case 1 exhibited strongly positive nuclear staining with the proliferation marker Ki67, (H) whereas a greater proportion (20% to 25%) were immunopositive in case 2. Hematoxylin counterstain; scale bar, 20 μm.