TY - JOUR T1 - Incidence of single hit Bcl-2 and Bcl-6 rearrangements in DLBCL: the Irish experience JF - Journal of Clinical Pathology JO - J Clin Pathol SP - 689 LP - 690 DO - 10.1136/jclinpath-2020-206725 VL - 73 IS - 10 AU - Kate Dinneen AU - Deirdre Mary Timlin AU - Kevin O'Hare AU - Jan Walker AU - Giuseppa Castriciano AU - Yvonne Connolly AU - Cliona Grant AU - Larry Bacon AU - Elisabeth Vandenberghe AU - Barbara Dunne AU - Michael Jeffers AU - Richard Flavin Y1 - 2020/10/01 UR - http://jcp.bmj.com/content/73/10/689.abstract N2 - Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin’s lymphoma. While many patients will be cured with Rituximab-CHOP, 30%–50% will either relapse or have disease refractory to treatment.1 The International Prognostic Index is not sufficiently accurate to stratify these patients into prognostic subgroups, thus gene expression profiling (GEP) and the identification of gene rearrangements (R) involving Myc, Bcl-2 and Bcl-6 are instead used for risk stratification. GEP or more commonly immunohistochemistry (IHC)-based algorithms are used to stratify patients according to their cell of origin (COO), broadly dividing them into germinal centre B (GCB), and non-GCB subgroups. The latter group incorporates the activated B-cell (ABC) subtype, which is associated with significantly worse outcomes when treated with standard chemotherapy regimens, as compared with the GCB subgroup.2 Double hit (DH) lymphomas are characterised by the presence of a Myc gene R with a concurrent Bcl-2 or Bcl-6 gene R, while triple hit (TH) lymphomas have all three. The rearrangement status of these lymphomas is reflected in the updated WHO classification of lymphoid neoplasms in 2017. DH/TH lymphomas account for 5%–10% of (morphologic) DLBCL.2 Interestingly, 80% of DH lymphomas have concurrent Myc and Bcl-2 R and are associated with the GCB subtype, while dual translocations of Myc and Bcl-6 are more commonly linked to the ABC phenotype.3 Overexpression of c-myc protein (defined as >40% positive neoplastic … ER -