IFNs were the first cytokines used in treating malignant tumor, with the approval of recombinant human IFNs, IFN-α2a and IFN-α2b for the treatment of Hairy Cell Leukemia and Kaposi’s sarcoma [19], IFNs provide fundamental defense strategies against viral infections, tumor growth and immune disorders. This evidence concerns the gene IFNA2 and Kaposi's sarcoma.