Immunofluorescence staining of mouse samples for basal/myoepithelial and luminal cytokeratins. (a) Wild-type (wt) mammary gland stained for Keratins 8/18 (red) and Keratin 5 (green) shows K8/18 expression in luminal epithelial cells and K5 expression in basal/myoepithelial cells. (b-f) Mouse models that show luminal-like gene expression patterns stained with K8/18 (red) and K5 (green). (g-k) Tumor samples that show basal-like, or mixed luminal and basal characteristics by gene expression, stained for K8/18 (red) and K5 (green). (j) A subset of Brca1Co/Co;TgMMTV-Cre;p53+/-tumors showing nodules of K5/K8/18 double positive cells. (l) A splindloid tumor stained for K8/18 (red) and smooth muscle actin (green).