Science gives overview of HPV in healthy adults
69% of Americans have 1 of 109 strains
Research might yield a better understanding of human papillomavirus (HPV) infection.
Results of a new genetic analysis indicate that 69% of healthy American adults are infected with one or more of 109 strains of the virus.1 Just four of the 103 men and women whose tissue DNA was publicly available through a government database had one of the two HPV types (16 or 18) known to cause most cases of cervical cancer, some throat cancers, and genital warts.1
In the two-year study, researchers from New York University (NYU) in New York City, J. Craig Venter Institute in Rockville, MD, and San Diego, Lawrence Berkeley National Laboratory in Berkeley, CA, Gene by Gene Ltd. in Houston, and Vanderbilt University in Nashville analyzed data made publicly available from the National Institutes of Health’s Human Microbiome Project, which is gathering information on microorganisms’ effects on human health. The study was lead by Yingfei Ma, PhD, a research scientist at NYU Langone Medical Center in New York City.
"The HPV community’ in healthy people is surprisingly more vast and complex than previously thought, and much further monitoring and research is needed to determine how the various non-cancer-causing HPV genotypes interact with the cancer-causing strains, such as genotypes 16 and 18, and what causes these strains to trigger cancer," said Ma in a press release accompanying the study’s release.
Tissue samples originally were collected from healthy study volunteers, ages 18 to 80, participating in the microbiome project. The scientists then used shotgun sequencing, which deciphers the genetic code of long strands of DNA in a random firing pattern, until a full picture appeared. The investigators then refined the analysis to only HPV strains by removing all human DNA sequences. Using special bioinformatics software developed at NYU Langone, the researchers compared what was left with known HPV national databases.
With this approach, scientists determined overall HPV prevalence at 68.9%, with specific prevalence as follows: skin, 61.3%; vagina, 41.5%; mouth, 30%; and gut, 17.3%.
Of the 109 HPV types, as well as additional unclassified types detected, most were undetectable by widely used commercial kits targeting the vaginal/cervical HPV types. These HPVs likely represent true HPV infections rather than transitory exposure because of strong organ tropism and persistence of the same HPV types in repeat samples, scientists conclude.1 In terms of the number of strains:
• Skin samples contained the most varied HPV strains, data shows. Eighty types of HPV were identified, including 40 that were found only in the skin.
• Vaginal tissue had the second most numerous strains, with analysis identifying 43 types of HPV, with 20 strains exclusive to the organ.
• Mouth tissue contained 33 types, of which five were exclusively oral in origin.
• Gut tissue contained six types, all of which were found in other organs.
The researchers are interested in exploring the role of HPV in cancers outside of the uterine cervix, says Zhiheng Pei, MD, PhD, FASCP, associate professor of pathology and medicine at NYU School of Medicine.
"The findings that HPV types inhabiting non-cervical body sites are different groups of HPV types pointed out the inadequacy of the cervical HPV detection kits for studies of HPV in other cancers," says Pei, a member of the research team. "We plan to develop a broad range HPV detection kit for use in surveys of HPV distribution in all types of HPV-related diseases throughout the body; the new method will allow assessing whether high risk’ HPV types could be re-defined according to different organs beyond the cervix."
The Human Microbiome Project (HMP) represents a new approach to understanding the microbial cells that inhabit the human body. Most of the human-associated microbial species have never been successfully isolated in the laboratory. Thanks to advances in DNA sequencing technologies, scientists now can conduct comprehensive examination of microbial communities without cultivation.
The National Institutes of Health has awarded a $7.4 million grant to researchers at Virginia Commonwealth University in Richmond to study pregnancy and preterm birth, using the Global Alliance to Prevent Prematurity and Stillbirth (GAPPS) Repository, a novel pregnancy biobank, and other academic institutions for specimens and data. The Multi-Omic Microbiome Study -- Pregnancy Initiative (MOMS-PI) will analyze the maternal and neonatal microbiome to assess its role as a cause of preterm birth. The study is a collaborative project with GAPPS, an initiative of Seattle Children’s Research Institute.
- Ma Y, Madupu R, Karaoz U, et al. Human papilloma virus community in healthy persons, defined by metagenomics analysis of Human Microbiome Project shotgun sequencing data sets. J Virol 2014; 88(9):4,786-4,797.