CCR6 and neoplasm: qPCR data revealed that the HER2-CXCR5-CCR6-CAR T cells displayed the highest copy number of HER2 cells in the tumor tissue (Fig. 6A), with the groups expressing either CXCR5 or CCR6 alone showing intermediate levels, both significantly exceeding those of the HER2-CAR T and Control-T group.