CD276 and cancer: B7-H3 CAR T cells demonstrated intense in vitro antitumor activity when cocultured with thyroid cancer cell lines at high ratios (cancer cell lysis: 87.5 ± 7.2% at the 1:1 E: T, 72.4 ± 14.4% at the 1:2 E: T), and CAR engagement-specificity was confirmed by the release of T cell effector cytokines mediated by B7-H3 CAR T cells when co-cultured with B7-H3 positive ATC cells (Fig. 4H).