High-grade B-cell lymphoma with MYC and BCL2 rearrangements (HGBCL-DH), historically termed double-hit lymphoma (DHL), accounts for 5–10% of diffuse large B-cell lymphoma (DLBCL) cases, a newly defined lymphoma condition in the 2016 version of the WHO lymphoma classification with a very poor prognosis1–3. The gene discussed is BCL2; the disease is B-cell non-Hodgkin lymphoma.