ZAP70 and B-cell chronic lymphocytic leukemia: The T cell specific zeta-associated protein 70 (ZAP-70), first identified by gene expression profiling of chronic lymphocytic leukemia (CLL) cells [1], has been the focus of many studies in the last few years, due to the ability of this molecule to act as an independent prognostic marker in CLL, when its expression is investigated by flow cytometry [2-5].