Fig. 2

Immunohistochemical expression of MUC1 (a–f). In normal breast tissue, MUC1 is constitutively expressed in the apical and luminal sites of the ductal epithelia with weak cytoplasmic positivity (a). MUC1 was notably expressed in invasive ductal carcinoma (b and c) and invasive lobular carcinoma (d and e) either in a luminal and cytoplasmic pattern (b and d) or in a cytoplasmic with membranous accentuation pattern (c and e). All mucinous carcinoma cases showed the luminal and cytoplasmic pattern (f). Original magnification × 400 (a) and × 400 (b–f)