Abstract 3118: Application of MUM1, CD10 and BCL6 IHC panel to a cohort of a hundred cases of diffuse large b-cell lymphoma on a tissue array

Abstract

Abstract Diffuse Large B-Cell Lymphoma (DLBCL) is clinically and morphologically heterogeneous and is the most common type of non-Hodgkin lymphoma. DLBCL can be divided into subgroups, namely, germinal center B-cell like (GCB), activated B cell-like (ABC) and type 3 based on gene expression profiles (1,2). Germinal center B-cell like has better survival compared to the ABC and type 3 profiles. It has been demonstrated that immunostaining of a panel of antibodies, CD10, BCL6 and MUM1, can be used to determine the GCB and non-GCB subtypes of DLBCL and predict survival similar to the cDNA microarray (3). The aim of the study is to evaluate several MUM1 clones, select the best clone, combine the clone with CD10 (clone 56C6) and BCL6 (clone LN22) and application of this panel to a cohort of 100 DLBCL cases. Six clones of MUM1 antibodies, mouse monoclonal antibodies EAU32, MUM1p, and MRQ-8 and rabbit monoclonal antibodies MRQ-43, EP190 and SP114 were evaluated. The clones were first screened for performance on a tonsil sample. All plasma cells and some germinal center B cells, as well as a small number of inter-follicular lymphocytes were expected to stain positive. Optimal dilution for each of the clones was determined independently before the best performing clone was selected. A tissue microarray containing 100 cases of DLBCL was stained with the panel and 97 cases were included in the data analysis (three cases were excluded from analysis due to tissue core loss for one case and due to dubious staining pattern for CD10 of two cases). All IHC assays were performed on the Thermo Scientific Autostainer using the two-step Quanto HRP polymer detection system. Slides were reviewed by a qualified pathologist. It was found that five of the six clones tested stained as expected except clone MRQ-43, which stained majority of the inter-follicular cells; therefore it was dropped from further evaluation. Clone EAU32 was found to produce the strongest staining intensity and was included with CD10 and BCL6 to constitute the antibody panel for DLBCL. A total of 21 cases were identified as GCB type including 15 CD10+ cases and 5 CD10-/ BCL6+/ MUM1- cases; A total of 76 cases were identified as non-GCB type including 55 CD10-/ BCL6- cases and 21 CD10- /BCL6+/ MUM1+ cases. The study identified a mouse monoclonal MUM1 antibody that is specific and provided strong immunostaining. The antibody panel of CD10, Bcl6 and MUM1 was effective in classifying the DLBCL into GCB and non-GCB subtypes according to Hans IHC Algorithm (3). 1. Rosenwald A et al, Lymphoma/Leukemia Molecular Profiling Project. N Engl J Med. 2002 Jun 20;346(25):1937-47. 2. Alizadeh AA et al., Nature. 2000 Feb 3;403(6769):503-11. 3. Hans CP et al. Blood. 2004 Jan 1;103(1):275-82 Citation Format: HAIPING LIU, Sharmini Muralitharan. Application of MUM1, CD10 and BCL6 IHC panel to a cohort of a hundred cases of diffuse large b-cell lymphoma on a tissue array. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3118.