Two new species of betatorqueviruses identified in a human melanoma that metastasized to the brain.

• Type of Material: Article
• Authors: Terry Fei Fan Ng, University of California; Jennifer A. Dill, University of Georgia; Alvin C. Camus, University of Georgia; Eric Delwart, University of California; Erwin Van Meir, Emory University
• Language: English
• Date: 2017-12-01
• Publisher: Impact Journals
• Publication Version: Final Published Version
• Copyright Statement: © 2017 Ng et al.
• License: Creative Commons Attribution 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.18632/oncotarget.22400
• Title of Journal or Parent Work: Oncotarget
• ISSN: 1949-2553
• Volume: 8
• Issue: 62
• Start Page: 105800
• End Page: 105808
• Grant/Funding Information: This study was supported in part by NIH grants CA163722, NS096236 and CA138292 (to EGVM).
• Keywords: neuro-oncology; metastasis; metagenomics; anellovirus; brain tumor
• Research Categories: Biology, Neuroscience; Health Sciences, Oncology; Biology, Virology

Abstract

The role of viral infections in the etiology of brain cancer remains uncertain. Prior studies mostly focused on transcriptome or viral DNA integrated in tumor cells. To investigate for the presence of viral particles, we performed metagenomics sequencing on viral capsid-protected nucleic acids from 12 primary and 8 metastatic human brain tumors. One brain tumor metastasized from a skin melanoma harbored two new human anellovirus species, Torque teno mini virus Emory1 (TTMV Emory1) and Emory2 (TTMV Emory2), while the remaining 19 samples did not reveal any exogenous viral sequences. Their genomes share 63-67% identity with other TTMVs, and phylogenetic clustering supports their classification within the Betatorquevirus genus. This is the first identification of betatorqueviruses in brain tumors. The viral DNA was in its expected non-integrated circular form, and it is unclear if the viruses contributed to tumor formation. Whether the viruses originated from blood, or the primary skin tumor could not be ascertained. Overall, our results demonstrate the usefulness of viral metagenomics to detect previously unknown exogenous virus in human brain tumors. They further suggest that active viral infections are rare events in brain tumors, but support a follow-up larger scale study to quantify their frequency in different brain tumor subtypes.