Tirabrutinib, a Bruton tyrosine kinase (BTK) inhibitor, has been used for recurrent or refractory diffuse large B-cell lymphoma (DLBCL).1 It has demonstrated a high overall response rate in recurrent or refractory DLBCL, with response rates ranging from 70% to 77% and complete response rates between 23% and 38%. The gene discussed is BTK; the disease is diffuse large B-cell lymphoma.