ESR1 and breast cancer: We used nine driver genes identified in this study (TP53, ESR1, GATA3, KMT2C, NCOR1, AKT1, NF1, RIC8A, RB1) as well as additional genes frequently altered in breast cancer (PTEN, PIK3CA, BRCA1, BRCA2, ERBB2, EGFR).