The use of Bruton tyrosine kinase (BTK) inhibitors such as ibrutinib to block B cell receptor (BCR) signaling has achieved a remarkable clinical response in several B cell malignancies including mantle cell lymphoma (MCL) and diffuse large B cell lymphoma (DLBCL). Acquired drug resistance, however, is significant and impacts long-term survival of these patients. Here we demonstrate that the transcription factor EGR1 is involved in ibrutinib resistance. We found that EGR1 expression is …