In EGFR mutation positive NSCLC, in-vitro experiments suggest that T-DM1 can overcome HER2 bypass track resistance in patients with EGFR mutated NSCLC.39 Two clinical studies evaluated T-DM1 treatment in NSCLC patients with HER2 alterations.40,41 However, both studies enrolled patients with HER2 as driver of tumourigenesis, and not necessarily as driver of TKI resistance. Here, ERBB2 is linked to non-small cell lung carcinoma.