Gene expression profiles of primary STAT1-/- estrogen receptor-alpha-positive (ERα+) mammary tumors show significant overlap with that of human ERα+luminal breast cancers. (A) Five primary STAT1-/- ERα+ mammary tumor datasets (S1_1, S1_2, S1_3, S1_4, and S1_6; orange) were analyzed with 232 annotated human breast cancer datasets and 13 other mouse mammary tumor models (purple) by hierarchical clustering using 96 genes known to be among those that are diagnostic for different human breast cancer subtypes . Genes are represented in rows, and datasets are represented in columns. Red represents genes that are overexpressed compared with the median, whereas green represents genes that are underexpressed compared with the median. The STAT1-/- ERα+ mammary tumors (orange) cluster closely to the human luminal breast cancers (blue) at the far left of the heatmap, underscoring the significant relatedness between the two cohorts. All human samples are colored by intrinsic subtype as determined in : blue = luminal, red = basal-like, pink = HER2+/ER-, yellow = claudin-low, and green = normal breast-like. Expression values of the datasets can be found in Additional file 3. (B) Display of seven genes that are important identifiers for the luminal subtype: KRT8, KRT18, XBP1, GATA3, MYB, AREG, and FOXA1 (from top to bottom). See Additional file 3 for the expression values of these genes. HER2, human epidermal growth factor receptor 2.