BATF3 and neoplasm: Strikingly, CAR T cells co-expressing BATF3 markedly enhanced tumor control at two subcurative doses (2.5 × 105 and 5 × 105 CAR+ cells) compared to control CAR T cells in an orthotopic human HER2+ breast cancer model (Fig. 5b,c and Extended Data Fig. 8c–f).