Further studies are needed to elucidate the precise mechanisms involved in determining the role of these different BCR profiles (compared to other prognostic factors such as ZAP70) in the distinct clinical behavior and outcome of both groups of M-CLL patients and facilitate implementation of assays for routine assessment of the HCDR3 hydropathy index in M-CLL in the clinical settings. Here, ZAP70 is linked to B-cell chronic lymphocytic leukemia.