ZAP70 and B-cell chronic lymphocytic leukemia: Suspected individuals are diagnosed with CLL if they express >5 × 109/L mature lymphocytes co-expressing CD5, CD19, and CD23 [4], along with a potential mutation in the immunoglobulin heavy-chain variable-region (IGHV) [5] or in the ζ-associated protein 70 (ZAP-70) gene [6,7].