However, when synthetic suppressor T cells with the synNotch→TGFβ1+CD25 circuit were injected along with CAR T cells, CAR T cell killing of the dual-antigen tumor (Her2+, CD19+) was suppressed, without affecting clearance of the single-antigen tumor (Her2+, CD19−) (Fig. 3B and fig. The gene discussed is ERBB2; the disease is neoplasm.