DAB389IL-2, which is a 58 kDa variant containing 97 fewer amino acids than its parent molecule, DAB486IL-2, showed a fivefold improvement in affinity for the IL-2R and an approximately 10-fold increase in cytotoxicity toward IL-2R-positive cancer cells (Bacha et al., 1991; Kiyokawa et al., 1991). The gene discussed is IL2RA; the disease is cancer.