Infectious Agents and Cancer (Nov 2022)

EBV persistence in gastric cancer cases conventionally classified as EBER-ISH negative

  • M. C. Siciliano,
  • S. Tornambè,
  • G. Cevenini,
  • E. Sorrentino,
  • M. Granai,
  • G. Giovannoni,
  • D. Marrelli,
  • I. Biviano,
  • F. Roviello,
  • H. Yoshiyama,
  • L. Leoncini,
  • S. Lazzi,
  • L. Mundo

DOI
https://doi.org/10.1186/s13027-022-00469-5
Journal volume & issue
Vol. 17, no. 1
pp. 1 – 12

Abstract

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Abstract Background The Epstein-Barr virus (EBV) causes various B-cell lymphomas and epithelial malignancies, including gastric cancer (GC) at frequencies ranging from 5 to 10% in adenocarcinomas (ADK) to 80% in GC with lymphoid stroma (GCLS). Using high-sensitivity methods, we recently detected EBV traces in a large cohort of EBV-negative B-cell lymphomas, suggesting a hit-and-run mechanism. Methods Here, we used routine and higher-sensitivity methods [droplet digital PCR (ddPCR) for EBV segments on microdissected tumour cells and RNAscope for EBNA1 mRNA] to assess EBV infection in a cohort of 40 GCs (28 ADK and 12 GCLS). Results ddPCR documented the presence of EBV nucleic acids in rare tumour cells of several cases conventionally classified as EBV-negative (ADK, 8/26; GCLS, 6/7). Similarly, RNAscope confirmed EBNA1 expression in rare tumour cells (ADK, 4/26; GCLS, 3/7). Finally, since EBV induces epigenetic changes that are heritable and retained after complete loss of the virus from the host cell, we studied the methylation pattern of EBV-specifically methylated genes (Timp2, Eya1) as a mark of previous EBV infection. Cases with EBV traces showed a considerable level of methylation in Timp2 and Eya1 genes that was similar to that observed in EBER-ISH positive cases and greater than cases not featuring any EBV traces. Conclusions These findings suggest that: (a) EBV may contribute to gastric pathogenesis more widely than currently acknowledged and (b) indicate the methylation changes as a mechanistic framework for how EBV can act in a hit-and-run manner. Finally, we found that the viral state was of prognostic significance in univariate and multivariate analyses.

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