ERBB2 and breast cancer: We observed that ER+PR+ and HER2+ breast cancer cells, and one TNBC cell line (MDA-MB-468) were sensitive to GSK3326595, whereas the other four TNBC cell lines and a widely used non-malignant breast epithelial cell line (MCF10A) were relatively resistant to GSK3326595, which was defined by IC50 < 4 μM and IC50 > 4 μM as previously described[32] (Fig. 1a and Supplementary Fig. 1a).