High-dose IFN-α (>1000 IU/ml) is FDA-approved as monotherapy for Kaposi’s sarcoma, follicular non-Hodgkin lymphoma, melanoma, and hairy-cell leukemia, and for adjuvant therapy of melanoma; overall clinical response rates are modest, and high-dose IFN-α toxicity is high, thus oncological use has diminished in recent times (52). This evidence concerns the gene IFNA2 and hairy cell leukemia.