In this study, we identified a G202C (position relative to start codon) missense mutation (Ala68Pro) in DNA binding domain of IRF-5 (IRF-5(P68) in tumor or transform B and T cell lines and peripheral blood from chronic lymphocytic leukemia (CLL) and adult T-cell leukemia/lymphoma (ATL) patients. This evidence concerns the gene IRF5 and lymphoma.