ERBB2 and neoplasm: As expected, while NECA had no significant effect on direct CAR T-cell cytotoxic activity (Supplementary Fig. 1A), it significantly suppressed IFNγ and TNF production by wild-type A2AR+/+ but not A2AR−/− CAR T cells following coculture with either E0771-Her2 (Fig. 1E, F) or 24JK-Her2 tumor cells (Supplementary Fig. 1B, C).