MRC1 and neoplasm: In addition, when comparing the groups with and without lymph node metastasis in PTC, there was significantly more macrophage infiltration around the tumour border in the group with lymph node metastasis [PG-M1 (p = 0.004), KP-1 (p = 0.035), CD163 (p = 0.032), CD206 (p = 0.016), and HO-1 (p = 0.013)] (Fig. 3c).