These MYC and BL-related groups do not feature clearly in the recent genetic classifications,5,6 but they are present in two new WHO designations as high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 translocation and high-grade B-cell lymphoma not otherwise specified.14 The difficulty in defining the optimum approach to this group is partly explained by the low frequency of groups such as double-hit lymphomas, and the absence of a clear biologic definition. The gene discussed is BCL6; the disease is B-cell non-Hodgkin lymphoma.