Tumor infiltrating macrophages reduce development of peritoneal colorectal carcinoma metastases.

Macrophages generally constitute a major component of tumor stroma, and possess either tumor growth promoting or inhibiting capabilities. Classically activated macrophages exert cytotoxicity and produce inflammatory cytokines, which limits tumor growth. By contrast, alternatively activated or M2 macrophages induce tumor progression by stimulating angiogenesis and proliferation.