CCL5 and hepatocellular carcinoma: To investigate the role of CCL5 in CTC survival and the formation of metastases via Treg recruitment in vivo, we injected 5 × 106 Hepa1–6 murine hepatoma cells with or without knockdown of CCL5 into the tail veins of immune-competent C57BL/6J mice (Fig. 5c, d).