EGFR and neoplasm: By recording the expression of red fluorescence protein (RFP), which is expressed by both the Tet-HER1-CAR-T cells and conventional HER1-CAR-T cells via RT‒PCR, both CAR-T cells after intravenous injection exhibited similar tumor-infiltration efficacy but were less effective than those in the lungs and liver (Fig. 3H).