Viral expression associated with gastrointestinal adenocarcinomas in TCGA high-throughput sequencing data

Daria Salyakina, Nicholas F Tsinoremas
<span title="">2013</span> <i title="Springer Nature"> <a target="_blank" rel="noopener" href="" style="color: black;">Human Genomics</a> </i> &nbsp;
Up to 20% of cancers worldwide are thought to be associated with microbial pathogens, including bacteria and viruses. The widely used methods of viral infection detection are usually limited to a few a priori suspected viruses in one cancer type. To our knowledge, there have not been many broad screening approaches to address this problem more comprehensively. Methods: In this study, we performed a comprehensive screening for viruses in nine common cancers using a multistep computational
more &raquo; ... h. Tumor transcriptome and genome sequencing data were available from The Cancer Genome Atlas (TCGA). Nine hundred fifty eight primary tumors in nine common cancers with poor prognosis were screened against a non-redundant database of virus sequences. DNA sequences from normal matched tissue specimens were used as controls to test whether each virus is associated with tumors. Results: We identified human papilloma virus type 18 (HPV-18) and four human herpes viruses (HHV) types 4, 5, 6B, and 8, also known as EBV, CMV, roseola virus, and KSHV, in colon, rectal, and stomach adenocarcinomas. In total, 59% of screened gastrointestinal adenocarcinomas (GIA) were positive for at least one virus: 26% for EBV, 21% for CMV, 7% for HHV-6B, and 20% for HPV-18. Over 20% of tumors were co-infected with multiple viruses. Two viruses (EBV and CMV) were statistically significantly associated with colorectal cancers when compared to the matched healthy tissues from the same individuals (p = 0.02 and 0.03, respectively). HPV-18 was not detected in DNA, and thus, no association testing was possible. Nevertheless, HPV-18 expression patterns suggest viral integration in the host genome, consistent with the potentially oncogenic nature of HPV-18 in colorectal adenocarcinomas. The estimated counts of viral copies were below one per cell for all identified viruses and approached the detection limit. Conclusions: Our comprehensive screening for viruses in multiple cancer types using next-generation sequencing data clearly demonstrates the presence of viral sequences in GIA. EBV, CMV, and HPV-18 are potentially causal for GIA, although their oncogenic role is yet to be established.
<span class="external-identifiers"> <a target="_blank" rel="external noopener noreferrer" href="">doi:10.1186/1479-7364-7-23</a> <a target="_blank" rel="external noopener" href="">pmid:24279398</a> <a target="_blank" rel="external noopener" href="">pmcid:PMC3906926</a> <a target="_blank" rel="external noopener" href="">fatcat:hg6a3vmogfdsdaie7c2f3kcsii</a> </span>
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