Abstract 7001: Profiling the CpG methylation patterns of Epstein-Barr virus DNA in lymphoma patients from Ethiopia
Authors: Feleke Seifegebriel T. , Shita Kidist Z. , Sherif Abdulaziz A. , Woldegebriel Fisihatsion T. , Weigel Christoph , Ahmed Elshafa H. , Zeleke Tamrat A. , Baiocchi Robert A. 
Published: March 2024

Abstract
Introduction: Epstein-Barr virus (EBV) is a tumor virus associated with various malignancies, driven by genetic mutations and epigenetic alterations, including DNA methylation. Abnormal CpG methylation holds promise as a diagnostic and therapeutic biomarker for EBV-associated tumors. However, the understanding of EBV's epigenetic mechanisms remain limited. Determining the methylation profile of EBV is crucial for gaining insights into the pathogenesis of EBV-associated tumors, developing diagnostic biomarkers, and exploring potential therapeutic strategies. Therefore, our study aimed to assess the CpG methylation profile of EBV DNA in lymphoma patients from Ethiopia.
Methods: This study enrolled 115 lymphoma patients from Tikur Anbessa Specialized Hospital in Addis Ababa, Ethiopia. Plasma and formalin-fixed paraffin-embedded blocks were collected from the participants, and isolation of DNA was performed from these samples. The methylation analysis was performed using the methylation-iPLEX assay. iPLEX capture and extension primers were designed to amplify and target EBV CpGs from bisulfite-converted DNA sequences. Ethical approval was also obtained from respected institutions.
Results: Among the 115 participants, 65.2% (n = 75) were male patients. The largest proportion (n = 35, 30.4%) fell within the 41-60 age group. Non-Hodgkin lymphoma (NHL) was diagnosed in 96 patients, while 19 had Hodgkin lymphoma (HL). In the NHL group, the majority (n = 27, 28.1%) were classified as diffuse large cell lymphoma, followed by follicular lymphoma (n = 24, 25%). Out of the different EBV genome methylation sites, we have identified 24 EBV genes to assess the methylation status of the EBV genome. Average methylation levels of these genes were ranged from 45% to 50%. Notably, the HL group exhibited significant heterogeneity in methylation levels, while the CpG methylation status of EBV genes in NHL subtypes demonstrated a consistent pattern. A significant proportion of our samples exhibited methylation loss in the lytic gene BZLF1 and at the origin of replication associated with lytic replication.
Conclusions: This study presents the first data from East Africa, shedding light on the EBV DNA methylation status in a diverse group of lymphoma patients. Further investigations in different locations are necessary to elucidate the impact of EBV DNA methylation on tumor progression.
Citation Format: Seifegebriel T. Feleke, Kidist Z. Shita, Abdulaziz A. Sherif, Fisihatsion T. Woldegebriel, Christoph Weigel, Elshafa H. Ahmed, Tamrat A. Zeleke, Robert A. Baiocchi. Profiling the CpG methylation patterns of Epstein-Barr virus DNA in lymphoma patients from Ethiopia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7001.