Patients with CLL cells that use unmutated immunoglobulin heavy chain (IGH) variable region (IGHV) and/or express high ZAP-70 generally have a more aggressive clinical course;27 however, such prognostic factors were not associated with a particular category of CLL (Figures 2d and e). This evidence concerns the gene ZAP70 and B-cell chronic lymphocytic leukemia.