Moreover, recent phase 1, 2 and 3 studies of the irreversible oral BTK inhibitor, ibrutinib have demonstrated excellent clinical activity and tolerability against a variety of B-cell malignancies including, chronic lymphocytic leukemia (CLL), mantle cell lymphoma, hairy cell leukaemia and diffuse large B-cell lymphoma in younger and older patients alike [8-16]. Here, BTK is linked to B-cell chronic lymphocytic leukemia.