Prognostic Sub-Grouping of Diffuse Large B-Cell Lymphomas into Germinal Centre And Post Germinal Centre Groups by Immunohistochemistry after 6 Cycles of Chemotherapy

Introduction: Diffuse large B-cell lymphomas (DLBCL) can be divided into germinal centre (GC-DLBCL)and post germinal centre (post GC-DLBCL) groups by applying immunohistochemical antibodies. As thesesubgroups respond differently to chemotherapy, it is possible at diagnosis to select a poor prognostic subgroupfor aggressive treatment.
Objective: To determine the frequencies of GC-DLBCL and post GC-DLBCL inpatients by immunohistochemistry (IHC) and the clinical response after six cycles of chemotherapy. Subjectsand
Methods: In this descriptive study conducted in AFIP and CMH, Rawalpindi and NORI, Islamabad, fromSeptember 2010 to September 2011, a total of 75 pretreatment cases of DLBCL diagnosed during the studyperiod were included. Cases were segregated in to GC-DLBCL and post GC-DLBCL groups according to resultsof immunohistochemistry markers CD10, BCL6 and MUM1. Immediate clinical response was assessed after 6cycles of chemotherapy. Response was divided into complete response, partial response, stable disease or relapseor progression.
Results: The mean age was 54.2±15. Males were 53 (70.7%). Forty (53.3%) cases comprisedthe GC-DLBCL group; 25(62.5%) of them showed a complete response. Most patients of the post GC-DLBCL19(54%) showed relapse/progression. Results of immediate clinical response in both prognostic subgroupswere significant (p<0.05). Results regarding positivity with immunohistochemical antibodies CD10 (p 0.011),BCL6 (p 0.013) and MUM1 (p 0.000) regarding immediate clinical response were also significant.
Conclusion:GC-DLBCL group shows better response to CHOP chemotherapy regimen. Immunohistochemistry should beused to further classify DLBCL as this can enable us to select aggressive group for aggressive treatment. Thismanuscript is important because the study is the first to becarried out exclusively in Pakistan or our part of theworld.