The severity of on-target-off-tumor activity may be modulated by the dose of CAR T cells applied, as another study that tested HER2-CAR T cells in sarcoma patients showed this to be safe if administered up to 1 × 108 CAR T/m2 compared to 1010 (or 6.25 × 1010 based on average female body surface area of 1.6 m2) CAR T cells in the former study (16). The gene discussed is ERBB2; the disease is neoplasm.