Fig. 2

Trastuzumab+pertuzumab combination is associated with HER2 downregulation. Cell viability of CTR, T, P, and T + P SkBr3 and BT474 cells treated with 0.1 μg/ml and 1 μg/ml T-DM1, respectively, for 48 h was evaluated by Crystal Violet Assay (a). The results are expressed as percentage of T-DM1-responsive cells relative to control cells, as mean +/− standard deviation. T-DM1 dose-response curves of T and T + P cells are reported for both SkBr3 and BT474 (b). The expression of phosphorylated and total HER2, HER3, EGFR, AKT and ERKs was evaluated by Western Blot (WB) following exposure to 1 μg/ml T-DM1 for 48 h (c). Representative pre- and post-therapy sections from 2 ABC patients, stained by immunohistochemistry with eosin-hematossilin and anti-HER2 antibody (d)