GATA3 and breast cancer: Given the direct regulation of GATA3 by BRCA1 shown above, and EMT-suppressive function of ectopic GATA3 in cell lines 26-28, we hypothesized that depletion of Gata3 in mice resulted in poorly differentiated mammary tumors with the induction of EMT which phenocopied Brca1-deficient tumors.