IFNA1 and hairy cell leukemia: The results indicate that HCL is potentially curable after cladribine treatment.19 HCL can be well-controlled with Cladribine: overall complete response rates ranged from 76 to 98%, median disease-free survival of 16 years, normal lifespan and rare HCL-related deaths.10 The response of hairy cell leukemia (HCL) to IFN-α is one of the most dramatic and specific effects in the whole of clinical oncology, but the mechanism of action of IFN-α in HCL remains unclear.20 Although IFN-α is highly active in HCL, IFN-α is not curative in this disease.