While many patients with FL achieve relatively long survival times following various standard therapies, a fraction of patients experience refractory or relapsed (R/R) disease or progress to a more aggressive form of lymphoma called diffuse large B cell lymphoma (DLBCL), which is characterized by a germinal center B cell (GCB)-like phenotype and/or increased interferon regulatory factor 4 (IRF4) expression.2 The gene discussed is IRF4; the disease is diffuse large B-cell lymphoma.