In mice xenografted with insulinoma, melanoma or prostate cancer cells and exposed to low radiation doses (2 Gy), macrophages in the TME show increased inducible nitric oxide synthase (iNOS) expression that favors their ability to inhibit abnormal tumor angiogenesis and promote tumor antigen-specific T-cell immunity (87). The gene discussed is NOS2; the disease is pancreatic insulinoma.