Clinical impact of the cell-of-origin classification based on immunohistochemistry criteria and Lymph2Cx of diffuse large B-Cell lymphoma patients in a South-east Asian population: a single center experience and review of the literature.

Background: Previous studies in Western populations, using immunohistochemistry (IHC) methods to subtype diffuse large B-cell lymphoma (DLBCL), suggest that germinal center B-cell lymphomas (GCBs) have improved outcomes. However, data in Asians have been limited and conflicting. This study aims to evaluate the prognostic impact of cell-of-origin (COO) subtyping by IHC and Lymph2Cx in South-East Asian (SEA) DLBCL patients, and to summarize the existing literature.Methods: A single-center retrospective analysis of 384 DLBCL patients diagnosed 2013-2018 who received Rituximab-based chemotherapy was performed. Hans and Lymph2Cx were used to assign COO and correlated with outcomes.Results: International Prognostic Index (IPI) score was associated with overall survival (OS) and progression-free survival (PFS). The 5-yr-OS for non-GCB versus GCB for COO by Hans was 70% versus 71% p=0.39, while 5-yr-OS for ABC versus GCB for COO by Lymph2Cx was 74% versus 92% p=0.19. The 5-yr-PFS for non-GCB versus GCB for COO by Hans was 65% versus 70% p=0.26, while 5-yr-PFS for ABC versus GCB for COO by Lymph2Cx was 64% versus 86% p=0.07.Conclusions: IPI is reaffirmed to be relevant in the rituximab era. COO by Hans has no prognostic significance, while subtyping by Lymph2Cx trends toward GCBs having better PFS and OS.