ERBB2 and glioblastoma: A phase I clinical trial, CAR2BRAIN (NCT03383978), has been underway since 2017 at the Johann W. Goethe University Hospital, in Germany, to evaluate the safety profile, tolerability, maximum tolerated dose (MTD), maximum feasible dose (MFD), and antitumor effects of NK-92/5.28.z cell therapy against relapsed or refractory HER2-positive GBM in patients undergoing biopsy or tumor resection surgery.