The use of BTK inhibitors is now incorporated into standard therapy for these conditions, and the genetic basis of acquired resistance in CLL, dominated by acquired mutation of BTK or PLCG2, has been well-studied.6,7 By contrast, the role of BCR inhibition in DLBCL remains less clear and little is known about the genetics of acquired resistance. The gene discussed is BTK; the disease is diffuse large B-cell lymphoma.