In a thought-provoking review published in the Annual Review of Virology, Patrick S. Moore and Yuan Chang explore the intriguing question: Are there more human cancer viruses yet to be discovered? Despite the identification of seven known human cancer viruses, including Epstein-Barr virus (EBV), human papillomavirus (HPV), and Merkel cell polyomavirus (MCV), the possibility of undiscovered viruses remains open.
The study highlights the challenges in virus discovery, such as hidden viral genomes, novel forms of viral persistence, and limitations in current sequencing technologies. Tumor sequencing and advanced molecular techniques like digital transcriptome subtraction (DTS) have significantly expanded our capacity to detect viral footprints in cancer, yet barriers still exist.
Key insights include:
The role of persistent infections: All known tumor viruses cause chronic infections, creating opportunities for oncogenic mutations.
Hidden viral mechanisms: Some viruses may evade detection due to non-coding RNA expression or integration into host genomes in ways that current methods overlook.
Future directions: Exploring under-studied cancers, particularly in low- and middle-income countries, may reveal new viral culprits.
While the answer remains uncertain, the authors emphasize that the search for new cancer-causing viruses is far from over. As technology evolves, so does the potential for groundbreaking discoveries in cancer virology.
