Hit-and-run hypothesis: revisiting the impact of EBV in malignancies.

Epstein-Barr virus (EBV) infects more than 90% of the global population and is etiologically linked to a wide spectrum of lymphoid and epithelial malignancies. Although its role as an oncogenic virus is well established, the mechanisms underlying EBV contribution to tumorigenesis remain undefined. This review revises the "hit-and-run" hypothesis in EBV-associated cancers, proposing that the virus may initiate oncogenic transformation before leaving tumour cells. The review summarizes current evidence of EBV episomal loss, integration into host chromosomes, and the challenges associated with detecting traces of viral genetic material. Recent advances in highly sensitive detection methods, such as quantitative polymerase chain reaction (PCR), RNAscope, and single-cell droplet digital PCR, have revealed viral traces in lymphomas and carcinomas previously considered as EBV-negative by conventional in situ hybridization, supporting a broader role for EBV involvement in oncogenesis. Moreover, tumours with EBV traces have similar epigenetic and mutational landscapes to EBV-positive patients, suggesting that EBV-induced alterations may continue to have an impact even after EBV loss. Despite these findings, it still remains unclear whether residual viral elements contribute to ongoing oncogenic signalling, epigenetic alterations, or immune modulation within the tumour microenvironment. Investigating these factors could improve our ability to stratify patients based on EBV status, refine diagnostic criteria, and develop more targeted treatment approaches.