IFNA1 and hairy cell leukemia: In addition to IL-2 (approved for metastatic kidney cancer and metastatic melanoma in 1992 and 1998), IFN-α has been approved by the USFDA for the treatment with hairy cell leukemia (1986) (11), and TNF (tasonermin) was licensed in Europe for irresectable soft tissue sarcoma in the 1999.