ERBB2 and neoplasm: Surprisingly, the level of phosphorylated HER2 did not decrease upon treatment with PZ/TZ (Fig. 5B).This might be due to difficulty to estimate in vivo how long after HER2‐targeting drug administration the tumor cells should be collected in order to detect the effect on the level of phosphorylation in the tissue because of the fast time scale of phosphorylation/dephosphorylation reactions.