Figure 2.

 HER receptor signalling. Phosphorylation of human epidermal growth factor receptors (HERs) 1, 2 and 3 after 14 days of therapy and control as detected by western blotting (A). Anti-HER2 C-terminal western blotting using day 14 tumours showed two bands, p185 and p95, but anti-extracellular domain (ECD) of HER2 blotting revealed another band (p110) consistent with the ECD produced by shedding from full-length HER2 (B). Anti-ECD and anti-C-terminal antibodies after 14 days in whole tissue sections using quantitative immunofluorescence (C). The ECD to C-terminus ratio (D) was increased in trastuzumab-treated groups (alone or combined), suggesting that increased shedding inhibited by trastuzumab.