Fig. 2

Analysis and prevalence of histology in tumors derived from mammary epithelial cell (MEC) populations. a through f Representative images of hematoxylin and eosin and cytokeratin staining of tumor histologies: acinar (a), papillary (b), solid adenocarcinoma (c), squamous (d), lipid rich (e), and sebaceous-like (f). Immunofluorescence staining was performed for basal keratin 14 (K14; red) and luminal keratin 8 (K8; green) (scale bar = 100 μm). ZsGreen fluorescence was not detected in the processed sections. Histological area per tumor was derived from luminal CD133+ cells (g), luminal CD133− cells (h), basal cells (i), and stem cells (j). Boxes above each column indicate tumors that were used for microarray analysis. Red boxes = basal subgroup; green boxes = luminal subgroup. Black circles mark tumors that were metastatic. k Average area of histology per MEC group (unpaired t test; n = number of tumors). l Representative images of estrogen receptor (ESR1) staining, including negative (left panel) and positive staining (right panel) (scale bar = 50 μm; n = number of tumors). m Quantification of ESR1 staining per MEC group (two proportion z test). n Quantification of ESR1 staining per histological specimen (two proportion z test). *p < 0.05, **p < 0.01, ***p < 0.0005, ****p < 0.0001