IFN-α2b is currently approved by the US FDA and EMA for the therapy of hairy cell leukemia (HCL), AIDS-related Kaposi's sarcoma, follicular lymphoma, multiple myeloma, melanoma, external genital/perianal warts (condylomata acuminata) and cervical intraepithelial neoplasms (both as a recombinant, unmodified protein, and as a pegylated variant), while IL-2 is licensed for the treatment of metastatic forms of melanoma and RCC. This evidence concerns the gene IL2 and hairy cell leukemia.