Characterization of human epidermal growth factor receptor 2 (HER2) chimeric antigen receptor (CAR) T-cell product. (A) HER2-CAR expression on nontransduced (NT) and transduced T cells (NT v HER2-CAR T cells, P < .001). Individual data points and mean are shown. (B) Phenotypic analysis of HER2-CAR T-cell product. CM, central memory (CD3+/CD45RO+/CD62L+); EM, effector memory (CD3+/CD45RO+/CCR7–/CD62L–). Box plot with whiskers (Tukey method) is shown. (C) Cytotoxicity assay using NT and HER2-CAR T cells as effectors and HER2-negative (K562 and MDA-MB-468 [MDA]) or HER2-positive (NCI-H1299 and LM7) cell lines as targets. Mean with standard deviation at an effector-to-target ratio of 20:1 is shown. K562: NT v HER2-CAR T cells, P = not significant (NS); MDA: NT v HER2-CAR T cells, P = NS; NCI-H1229: NT v HER2-CAR T cells, P < .001; LM7: NT v HER2-CAR T cells, P < .001.