In particular, the Bruton’s tyrosine kinase (BTK) inhibitors8 such as ibrutinib,9,10 are an effective therapy leading to sustained responses, although patients may become resistant and relapse.11 Ibrutinib promotes CLL cells mobilization from the tissues to the PB12 where they lose the protective effect exerted by the microenvironment and eventually undergo apoptosis. The gene discussed is BTK; the disease is B-cell chronic lymphocytic leukemia.