While no severe side effects or dose-limiting toxicities were reported upon treatment of AML and glioblastoma patients with CD33−and HER2-specific CAR NK-92 cells in early phase clinical trials,11,12 this may be different in future studies depending on the chosen CAR target antigen, effector cell dose or duration of treatment. The gene discussed is ERBB2; the disease is acute myeloid leukemia.