MRC1 and neoplasm: M1 macrophages (CD86+ and CD80+) release pro-inflammatory cytokines (e.g., IL-6, IL-12, TNF-α) to play an anti-tumor role, while M2 macrophages (CD206+) release pro-tumor cytokines (e.g., IL-4, IL-10, IL-13) to promote tumor progression and metastasis (11).