What about the physiopathological role of ZAP-70 expression in chronic lymphocytic leukemia? Volume 12, issue 4, Juillet-Août 2006


See all figures

Laboratoire d’hématologie, hôpital Nord, 80000 Amiens, INSERM E351, Faculté de médecine, rue des Louvels, 80000 Amiens

ZAP-70, a Syk family cytoplasmic protein tyrosine kinase (PTK), is required to couple the activated T-cell antigen receptor (TCR) to downstream signaling pathways. This kinase, known to be absent in normal peripheral B cells, is expressed in the majority of the poorer prognosis unmutated CLL and absent in most cases with mutated IgVH genes and has emerged as a protein of potential prognostic importance. ZAP-70 has been shown to be functionally important in the CLL cases in which it is expressed. Different studies provide evidence that its expression in CLL B cells renders IgM signaling more effective and thereby could contribute to the more rapidly progressive clinical course of ZAP-70-positive CLL. The role of ZAP-70 is also important in B cell development in mice and there is preliminary evidence for its expression in human B cell progenitors and activated B cells. Whether its expression in a sub-set of CLL cases is a result of a more activated cell type or a reflection of the stage of maturation of the transforming event(s) in CLL is open to debate.