TAMs are broadly classified into classically activated M1 macrophages that produce effector molecules such as reactive oxygen and nitrogen intermediates, and TNFα, to limit tumor growth, and alternately activated M2 macrophages that promote tumor growth and metastasis by secretion of matrix-degrading enzymes, angiogenic factors and immunosuppressive cytokines/chemokines (28). The gene discussed is TNF; the disease is neoplasm.