In solid tumors, tumor-associated macrophages (TAMs) are abundant and control multiple aspects of tumor growth (1, 2), including immune suppression and evasion through mechanisms such as TGF-β and IL-10 (3–8); the promotion of angiogenesis through the secretion of VEGF (9–12), which mediates resistance to chemotherapy by protecting tumors from oxidative stress; and the promotion of tumor growth after radiation (13–18). The gene discussed is IL10; the disease is neoplasm.