Interleukin-12 and granulocyte-macrophage colony-stimulating factor (GM-CSF) induce the activation of tumor-resident CD8 T effector/memory cells (Tem) followed by cytotoxic CD8 T effector cell expansion, a population that is a potent in situ resource for successful reactivation of systemic antitumor T cell immunity.5 The gene discussed is CD8A; the disease is neoplasm.