Figure 2

Immunohistochemical phenotypes of epithelial-to-mesenchymal transition tumors in the mouse mammary gland in Tm(Stat1^-/-) mice. Immunohistochemistry for various breast cell markers in serial sections of a mouse epithelial-to-mesenchymal transition (EMT) mammary tumor showing both epithelial and spindle cell components. Left: Cytokeratin (CK) staining for three epithelial markers: (A) luminal CK8/18, (C) basal CK5, and (E) progenitor CK6 cells. Right: Staining for two mesenchymal markers, (B) vimentin (VIM) and (D) smooth muscle actin (SMA), and (F) the epithelial junctional complex marker cadherin-1 (CDH1). (A), (B) The images are arranged to highlight the dual CK-VIM staining pattern of EMT tumors. The presence of (C), (D) basal cell antigens and (E) progenitor cell CK in conjunction with (F) loss of CDH1 characterizes the malignant breast epithelial population. All images were captured from whole-slide images acquired with the Aperio ScanScope XT (Aperio, Carlsbad, CA, USA) using the 20× objective. All markers were detected using an indirect immunoperoxidase procedure with diaminobenzidine as the chromagen and hematoxylin as the counterstain. (E) Bar = 100 μm. The Tm(Stat1^-/-) mice were kindly provided by Dr RD Schreiber [109].