ZAP70 and B-cell chronic lymphocytic leukemia: An interaction of UGT2B17 with additional components of the BCR pathway was observed, including with the proto-oncogene tyrosine kinase LYN also essential to CLL progression, the spleen tyrosine kinase (SYK) closely related to ZAP70, as well as with the lymphocyte-specific protein tyrosine kinase and activator of ZAP70, and LCK (Figure 4C,D).