Based on successful preclinical results with IL-2 therapy in cancer models, high-dose IL-2 (aldesleukin; trade name Proleukin) was the first FDA-approved cancer immunotherapeutic drug for treating metastatic RCC in 1992 and metastatic melanoma in 1998, with substantial antitumor efficacy1,64. This evidence concerns the gene IL2 and metastatic melanoma.