LAUSR

Emerging biologic subsets and new prognostic markers are significantly and adversely affecting curability after standard chemoimmunotherapy for aggressive B‐cell lymphomas. The identification of concurrent MYC and B‐cell CLL/lymphoma 2 (BCL2) deregulation, whether at a genomic or protein level, has opened a new era of investigation within the most common subtype of aggressive B‐cell lymphomas. Double‐hit lymphoma (DHL), defined as a dual rearrangement of MYC and BCL2 and/or B‐cell CLL/lymphoma 6 (BCL6) genes, is an uncommon subset accounting for 5% to 7% of all diffuse large B‐cell lymphomas (DLBCLs), and long‐term survivors are rare. Double‐expressor lymphoma (DEL), defined as overexpression of MYC and BCL2 proteins not related to underlying chromosomal rearrangements, is not a distinct entity in the current World Health Organization classification but accounts for 20% to 30% of DLBCL cases and also has poor outcomes. There are many practical considerations related to identifying, determining the prognosis of, and managing DHL and DEL.