Epstein-Barr Virus MicroRNAs as Key Regulators of Lymphoma Pathogenesis: Immune Evasion Mechanisms and Therapeutic Opportunities.

The ubiquitous human gamma-herpesvirus Epstein-Barr virus (EBV) infects over 90% of adults globally and was the first human virus identified with oncogenic potential. EBV enters a lifelong persistence in the host via a finely regulated life-cycle comprising primary infection, latency and lytic reactivation. Within infected B-cells and epithelial cells, EBV encodes a distinct repertoire of microRNAs (miRNAs), primarily from the BART (BamHI A rightward transcript) and BHRF1 (BamHI H rightward open reading frame) clusters, which play pivotal roles in modulating both viral and host gene expression. These viral miRNAs contribute to key oncogenic processes: by dampening apoptotic responses (e.g., via targeting PUMA, Bim, and PTEN), promoting proliferation of latently-infected B-cells, inhibiting host immune responses (e.g., via down-regulation of CXCL-11 by miR-BHRF1-3), and promoting epithelial-mesenchymal transition (EMT) and metastasis through modulation of E-cadherin and other adhesion molecules. In human lymphomas, such as Burkitt lymphoma, Hodgkin lymphoma, and EBV-positive diffuse large B-cell lymphoma, the interplay of latent viral gene expression, miRNA-mediated regulatory networks, and host microenvironmental factors underlies malignant transformation and disease progression. Emerging evidence also supports the utility of EBV-encoded miRNAs as diagnostic and prognostic biomarkers in EBV-associated cancers. Importantly, therapeutic strategies aimed at interrupting viral miRNA function, restoring host tumor-suppressor pathways, and re-sensitizing tumor cells to immune surveillance hold promise. This review synthesizes current mechanistic insights into EBV-encoded miRNAs in oncogenesis, elaborates on their roles in lymphoma pathogenesis, and evaluates the translational potential of miRNA-targeted therapies in EBV-associated malignancies.