The irreversible BTK inhibitor ibrutinib was the firstFDA-approved BTKi and is associated with high response rates in relapsed/refractoryCLL, WM, and MCL and in chronic graft versus hostdisease.17,18 However, with a broad selectivity profile,ibrutinib inhibits the whole TEC family, EGFR, JAK3, Her2, Blk, andITK kinases. This evidence concerns the gene BTK and mantle cell lymphoma.