Bruton tyrosine kinase (BTK) is a non-receptor tyrosine kinase indispensable for B lymphocyte development and differentiation1–3which plays a significant role in survival, proliferation, and adhesion of malignant B lymphocytes in chronic lymphocytic leukemia (CLL)4–7. This evidence concerns the gene NTRK1 and B-cell chronic lymphocytic leukemia.