ZAP70 and B-cell chronic lymphocytic leukemia: CLL patients were stratified into high risk (ZAP-70 ≥ 20%, IgVH ≥ 98% homology) and low risk (ZAP-70 < 20%, IgVH < 98% homology) based on ZAP-70 expression and IgVH homology status [35].