{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"ZAP-70 is an abbreviation for zeta-chain-associated protein kinase 70 (70 kDa). ZAP-70 is a member of the protein-tyrosine kinase family, normally expressed in T-cells and natural killer cells. ZAP-70 initiates a signaling pathway downstream of an activated T cell receptor. Mutations or deficiencies in ZAP-70 can lead to combined immunodeficiency, characterized by recurrent infections and impaired immune responses. According to literature, ZAP-70 expression is notably associated with chronic lymphocytic leukemia (CLL)."}]}]}