ERBB2 and breast carcinoma: Importantly, the HER2-positive breast cancer cell lines tested in this study (BT474, SKBR3, AU565, EFM192A) are sensitive to submicromolar concentrations of zanubrutinib (Table 1 ; Fig. 4), which are lower than the maximum plasma concentration (cmax) in humans (1.4 μM for a dose of 320 mg per os) [32].