M2 macrophages secrete a variety of factors such as VEGF, TGF-β, and MMPs that facilitate tumor growth. VEGF promotes the formation of new blood vessels, supplying the tumor with necessary nutrients and oxygen. TGF-β suppresses anti-tumor immune responses, allowing the cancer cells to evade the immune system. MMPs degrade the extracellular matrix, enabling cancer cells to invade surrounding tissues and metastasize to distant sites.
