ESR1 and breast cancer: Although terminated, a neoadjuvant phase II trial of estrogen receptor (ER)− breast cancers, including TNBC, appraised the biologic effectiveness of dasatinib, a multi-targeted TKI targeting the Src family, breakpoint cluster region-abelson (BCR-ABL), PDGFR-β, and c-Kit, with interim analysis indicating stable disease in 15 out of 22 patients (NCT00817531).