ZAP70 and B-cell chronic lymphocytic leukemia: In our research, we have also confirmed the downregulation of Syk tyrosine kinase in ZAP70‐low group, and for the first time describe the correlation between the mRNA and protein expression of signaling tyrosine kinases in different subsets of B‐CLL samples, however, a quantitative measurement of phosphorylation pattern of signaling tyrosine kinases as a hallmark of their functionality is an important issue for further investigation.