Figure 3.

Immunohistochemical analysis of the claudin 1 protein in normal breast tissue and breast cancer. Representative claudin 1 staining in human invasive breast cancer, and healthy normal mammary ductal epithelial cells are shown. Tumor depicted in panel A shows both membrane (black arrows) and cytoplasmic staining (red arrows), while the tumor in panel B shows only cytoplasmic staining (red arrows). (C) Normal ductal epithelial cells in a healthy mammary gland tissue show high levels of claudin 1, while the basal-like myoepithelial cells (depicted by the arrows) are primarily negative. Scale bars = 20μm.