ERBB2 and cancer: Although T‐DM1 has been successfully translated to the clinic for HER2‐positive cancer patients, its lack of efficacy in tumor cells expressing relatively low HER2 levels is an important unmet clinical need.[26] T‐DM1 did not have any effect in the HER2 ++ GC PDX model but the LCB‐ADCs still showed dramatic therapeutic efficacy in these mice.