Ventana Medical Systems, Inc. ZAP-70 760-4278

ZAP-70 is a 70 kD protein tyrosine kinase found in T cells and natural killer cells. Control of this protein translation is via the IgVH gene. ZAP-70 protein is expressed in leukemic cells of approximately 25% of Chronic Lymphocytic Leukemia (CLL) cases as well. ZAP-70 expression is an excellent surrogate marker for the distinction between the Ig-mutated (ZAP-70 negative) and Ig-unmutated (ZAP-70 positive) CLL subtypes and can identify patient groups with divergent clinical courses. The ZAP-70 positive Ig-unmutated CLL cases have a poorer prognosis.