Strikingly, PARP inhibition can mitigate the M2-inducing effects of IL-4, IL-10, and M-CSF and results in large, highly phagocytic macrophages (Figure 1) with remarkable anti-tumor activity ex vivo, suggestive of direct reprogramming of tumor macrophages by PARP inhibition. The gene discussed is PARP1; the disease is neoplasm.