ZAP-70 (Zeta-associated protein of 70-kD)
From Standard of Care
A cytoplasmic tyrosine kinase essential for signaling molecule for T-lymphocytes and natural killer cells.
Anomalously expressed in CLL cells with unmutated IgVh genes and may enhance the signaling process when B-cell receptor is engaged.
Associated with CD3 receptor complex of the lymphocytes ad the Syk family of tyrosine kinases.
Plays a role in signaling, activation and phosphorylation of downstream targets.
T cells contain more ZAP-70 than B cells.
Intracellular ZAP-70 content correlates with IgVh mutation.
Expression in CLL associated with a more rapid progression and shorter survival.
Can be expressed in other hematologic neoplasms aside from CLL, such associated precursor B cell ALL, mantle cell lymphoma, diffuse large B cell lymphoma and Burkitt’s lymphoma.