Comparing three radiation regimens, 20 Gy × 1, 8 Gy × 3, and 6 Gy × 5, we demonstrated a marked difference between single dose and fractionated regimens, in the ability to synergize with anti-CTLA-4 antibody treatment and induce an anti-tumor immune response able to inhibit tumor locally, at the irradiated site, and systemically (Dewan et al., 2009). The gene discussed is CTLA4; the disease is neoplasm.