Poor survival with high-dose chemotherapy and autologous stem cell support in double-hit and double-expressor B-cell lymphomas

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease both in biology and clinical behavior. Approximately two thirds of patients achieve prolonged disease free survival and cure after induction with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) chemoimmunotherapy (1). Much of the research in the field has been devoted to characterizing the biology of those with progressive disease or who ultimately relapse. Aberrations of MYC, BCL2 and BCL6 have been implicated in a proportion of these cases and include both translocations involving these genes as well as abnormal protein expression of MYC and BCL2. In recognition of the unique clinical behavior of translocations involving MYC, BCL2 and BCL6, a provisional entity of high grade B-cell lymphoma (HGBL) with rearrangements of MYC and BCL2 and/or BCL6 has been included in the 2016 revision of the World Health Organization (WHO) classification of lymphoid neoplasms (2). These have been referred to as double-hit lymphomas (DHL), or in the case of DLBCL with co-expression of MYC and BCL2, double-expressor lymphomas (DEL).