In the context of anti-cancer treatment setting, IFNs were mostly employed against hematological diseases, with MPNs patients showing the strongest responses; historically, IFNα was able to induce major responses in chronic myeloid leukemia (CML) and therefore has been a mainstay of treatment in this field before the approval of tyrosine kinase inhibitors (TKIs). This evidence concerns the gene IFNA1 and chronic myelogenous leukemia, BCR-ABL1 positive.