GATA3 expression levels classify breast cancer patients in ER groups. (A-D) GATA3 expression levels divide patients according to their ER status in multiple cohorts of patients. On each sub-figure, the left panel presents expression levels of GATA3 across the population of samples in each GEO dataset. ER- patients are tagged blue and ER+ patients are tagged red. The right panel presents the same data, in a bars and whiskers format. P-values for each dataset are: (A) 4.31E-27, (B) 3.49E-35, (C) 2.32E-17 and (D) 4.11E-40. (E) GATA3 expression levels are correlated with ER status in breast cancer lines. Relative GATA3 transcript levels in ER+ and ER- breast cancer lines are compared to normal mammary cells. GATA3 transcripts were detected by RT-qReal Time PCR and normalized to beta-actin. ER, estrogen receptor; GATA3, GATA binding protein 3.