ERBB2 and breast cancer: When MMV652103 (Figure 2A(Fig. 2)) was tested in a range of breast cancer cells with varying hormone receptor status the following IC50 values were obtained: 2.2 μM for MCF7 (ER+), 2.9 μM for T47D (ER+), 7.3 μM for BT474 (HER2+), 14.3 μM for MDA-MB-231 (TNBC) (Figure 2B(Fig. 2)).