ESR1 and neoplasm: Hierarchical clustering analysis (Figure 13A) demonstrated the high similarity in TF expression between G-2 cell cultures and tumor samples and revealed two large gene clusters containing genes whose expression in comparison to normal mammary gland is either significantly reduced, e.g. Esr1, Cebpa, Sox17, Sox18, Hoxc6, Id4, Pparg, and Foxa1, or enhanced, e.g. Ehf, Elf5, Etv1, Etv4, Etv5, Hmga1, Foxc1, Foxm1, Sox10 and Tcfcp2l1. We considered that the TFs from the latter group are essential for differentiation into the phenotypic subsets observed in G-2 cultures.