A significant example of toxicity associated with the non-exclusive expression of a TAA on tumor cells is illustrated by the case of a patient with metastatic colorectal cancer who received an infusion of autologous CAR-T cells directed against the human epidermal growth factor receptor-2 (HER2)/neu (ErbB2) and who experienced acute respiratory distress and then fatal pulmonary edema [25]. The gene discussed is ERBB2; the disease is metastatic colorectal cancer.