A further decrease in red fluorescence signal was observed in MOSs after 24 and 48 h of co-culture of anti-HER2 CAR-T cells (Figure 4E), whereas there was an increase in red fluorescence signal over time in HER2+ CRC MOSs co-cultured with PBMCs (Figure 4F). Here, ERBB2 is linked to colorectal carcinoma.