Figure 2.

Hierarchical clustering analysis of the 42 breast cancer gene expression studies, classified them in four groups: the intrinsic subtypes, response to chemotherapy, stromal/extracellular matrix (ECM) and signatures enriched in cell cycle genes. It can clearly be seen that related signatures such us intrinsic subtype and ER-alpha status on the one hand, or stromal and extracellular matrix signatures on the other hand, have a large overlap relative to other gene expression signatures.