Recombinant therapeutic proteins that have been widely used in cancer are enzymes (Elspar, Oncaspar, and Elitek), toxins (denileukin diftitox or ontak), monoclonal antibodies (Zevalin, Mylotarg, Bexxar, Herceptin, Avastin, Erbitux, Rituxan, Vectibix, and Campath), and cytokines (interleukin-2, interferon-αn3, interferon-β1, and interferon-α2b). The gene discussed is IL2; the disease is cancer.