Analysis of Diffuse Large B Cell Lymphoma using Immunohistochemistry to Identify Double Expressor Diffuse Large B Cell Lymphoma among Germinal Centre and Non Germinal Centre B Cell Subtypes

ABSTRACT Diffuse large B cell lymphoma (DLBCL) within non-Hodgkin lymphoma has several morphologic and clinicopathologic variants. DLBCL has two prognostically important subtypes, germinal center B cell (GCB) and nongerminal center (Non-GCB) with the non-GCB having an inferior outcome. Immunohistochemical co-expression of cellular myelocytomatosis (CMYC) and BCL2 in DLBCL has poor prognosis and is considered as double-expressor lymphoma (DEL). This study was done to identify DEL using immunohistochemistry among GCB and non-GCB DLBCL and to assess their treatment response. A retrospective analysis of 97 DLBCL cases received in our department was done. Formalin-fixed paraffin blocks were used to prepare Hematoxylin and eosin–stained sections, immunohistochemical subtyping (into GCB and non-GCB using CD10, BCL6, and MUM1) and further to identify DEL (using CMYC and BCL2). Analysis was done using Chi-square test (Statistical Package for Social Sciences version 18), and P <.05 was considered significant. Kaplan-Meier test was used to estimate overall survival. Of the total 97 DLBCL cases analyzed, 33 (34%) were DEL and 64 (66%) were non-DEL. Of the DEL, 13 (13.40%) were GCB subtype and 20 (20.6%) were non-GCB. However, there was no statistically significant difference in the overall survival and treatment response between DEL and non-DEL. In this study, we found that DEL constituted about one-third of the total DLBCL and within the DEL non-GCB subtype was more common. Further studies should be performed in large population to study the difference in clinical outcome.