Viruses are between 27,000 to 48,500 years old and not dangerous, but researchers say thawing permafrost may one day release pathogens capable of infecting humans
Last fall, European researchers working with virologists and genetic scientists at the Aix-Marseille University in France reported having revived and characterized 13 previously unknown “zombie” viruses isolated from Siberian permafrost samples, including one that was almost 50,000 years old. This will be of particular interest to microbiologists and clinical laboratory managers since these organisms are new to science and may be precursors to infectious agents active in the world today.
The work of the European scientists demonstrates how advancements in genome sequencing and analysis of DNA data are becoming, faster, less expensive, and more precise. That’s good because the researchers warned that, should the permafrost continue to thaw, other previously dormant viruses could be released, posing potential risks for public health.
The pathogens isolated by the researchers are so-called “giant viruses” that infect Acanthamoeba, a commonly found genus of amoeba, and thus are not likely to pose an immediate health threat, the researchers wrote.
However, the scientists expressed concern. “We believe our results with Acanthamoeba-infecting viruses can be extrapolated to many other DNA viruses capable of infecting humans or animals. It is thus likely that ancient permafrost … will release these unknown viruses upon thawing,” they stated in their Viruses paper.
It’s unknown how long the viruses “could be infectious once exposed to outdoor conditions (UV light, oxygen, heat), and how likely they will be to encounter and infect a suitable host in the interval,” they added. However, “the risk is bound to increase in the context of global warming, in which permafrost thawing will keep accelerating, and more people will populate the Arctic in the wake of industrial ventures.”
“In nature we have a big natural freezer, which is the Siberian permafrost,” virologist Paulo Verardi, PhD (above), head of the Department of Pathobiology and Veterinary Science at the University of Connecticut, told The Washington Post. “And that can be a little bit concerning.” However, “if you do the risk assessment, this is very low. We have many more things to worry about right now.” Nevertheless, clinical laboratories may want to remain vigilant. (Photo copyright: University of Connecticut.)
Extremely Old, Very Large Viruses
The newly discovered viruses were found in seven different permafrost samples. Radiocarbon dating determined that they had been dormant for 27,000 to 48,500 years. But viruses contained in permafrost could be even older, the researchers wrote, as the time limit is “solely dictated by the validity range of radiocarbon dating.”
In their Viruses paper, the researchers noted that most of the 13 viruses are “at a preliminary stage of characterization,” and others have been isolated in the research laboratory “but not yet published, pending their complete genome assembly, annotation, or detailed analysis.”
“Every time we look, we will find a virus,” study co-author Jean-Michel Claverie, PhD, told The Washington Post. “It’s a done deal. We know that every time we’re going to look for viruses—infectious viruses in permafrost—we are going to find some.”
Claverie is a professor emeritus of genomics and bioinformatics in the School of Medicine at Aix-Marseille Université in Marseille, France. He leads a university laboratory known for its work in “paleovirology,” and in 2003, discovered the first known giant virus, dubbed Mimivirus. The research team included scientists from Germany and Russia.
According to CNN, unlike regular viruses that generally require an electron microscope to be viewed, giant viruses can be seen under a standard light (optical) microscope. Claverie’s laboratory previously isolated giant viruses from permafrost in 2014 and 2015.
Protecting Against Accidental Infection
To demonstrate the infectious potential of the viruses, the researchers inserted the microbes into cultured amoeba cells, which the researchers describes as “virus bait,” The Washington Post reported. One advantage of using Acanthamoeba cultures is to maintain “biological security,” the researchers wrote in their paper.
“We are using [the amoeba’s] billion years of evolutionary distance with human and other mammals as the best possible protection against an accidental infection of laboratory workers or the spread of a dreadful virus once infecting Pleistocene mammals to their contemporary relatives,” the paper noted. “The biohazard associated with reviving prehistorical amoeba-infecting viruses is thus totally negligible compared to the search for ‘paleoviruses’ directly from permafrost-preserved remains of mammoths, woolly rhinoceros, or prehistoric horses.”
The paper cites earlier research noting the presence of bacteria in ancient permafrost samples, “a significant proportion of which are thought to be alive.” These include relatives of contemporary pathogens such as:
“We can reasonably hope that an epidemic caused by a revived prehistoric pathogenic bacterium could be quickly controlled by the modern antibiotics at our disposal,” the researchers wrote, but “the situation would be much more disastrous in the case of plant, animal, or human diseases caused by the revival of an ancient unknown virus.”
However, according to The Washington Post, “Virologists who were not involved in the research said the specter of future pandemics being unleashed from the Siberian steppe ranks low on the list of current public health threats. Most new—or ancient—viruses are not dangerous, and the ones that survive the deep freeze for thousands of years tend not to be in the category of coronaviruses and other highly infectious viruses that lead to pandemics.”
Cornell University virologist Colin Parrish, PhD, President of the American Society for Virology, told The Washington Post that an ancient virus “seems like a low risk compared to the large numbers of viruses that are circulating among vertebrates around the world, and that have proven to be real threats in the past, and where similar events could happen in the future, as we still lack a framework for recognizing those ahead of time.”
Anthony Fauci, MD, former Director of the National Institute of Allergy and Infectious Diseases (NIAID), responded to an earlier study from Claverie’s lab by outlining all the unlikely events that would have to transpire for one of these viruses to cause a pandemic. “The permafrost virus must be able to infect humans, it must then [cause disease], and it must be able to spread efficiently from human to human,” he told The Washington Post in 2015. “This can happen, but it is very unlikely.”
Thus, clinical laboratories probably won’t see new diagnostic testing to identify ancient viruses anytime soon. But it’s always best to remain vigilant.
Studies could lead to new prognostic biomarkers and clinical laboratory diagnostics for cancer
Might fungi be involved in human cancers? Two separately published studies have found fungal DNA in various cancers in the human body. However, the researchers are unclear on how the fungi got into the cancer cells and if it is affecting the cancers’ pathology. Nevertheless, these discoveries could lead to utilizing tumor-associated fungal DNA as clinical laboratory diagnostics or prognostic biomarkers in the fight against cancer.
“The finding that fungi are commonly present in human tumors should drive us to better explore their potential effects and re-examine almost everything we know about cancer through a ‘microbiome lens,’” said Ravid Straussman, MD, PhD (above), a principal investigator at Weizmann Institute of Science and one of the authors of the study in a UCSD press release. These findings could lead to new clinical laboratory diagnostics and prognostic biomarkers. (Photo copyright: Weizmann Institute of Science.)
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Microbiome Key to Cancer Biology and Detection
To perform their research, the team examined 17,401 samples of patient tissues, blood, and plasma across 35 different types of cancers in four independent cohorts. They discovered fungal DNA and cells in low abundances in many human cancers.
“The existence of fungi in most human cancers is both a surprise and to be expected,” said biologist Rob Knight, PhD, founding Director of the Center for Microbiome Innovation and Professor of Pediatrics and Computer Science and Engineering at UC San Diego in a UCSD press release. “It is surprising because we don’t know how fungi could get into tumors throughout the body. But it is also expected because it fits the pattern of healthy microbiomes throughout the body, including the gut, mouth and skin, where bacteria and fungi interact as part of a complex community.”
The main highlights of this study include:
Fungi detected in the different cancer types were often intracellular.
Multiple fungal-bacterial-immune ecologies were detected across tumors.
Intratumoral fungi stratified clinical outcomes, including immunotherapy response.
Cell-free fungal DNA found in both healthy and cancer patients in early-stage disease.
Fungi found on the human body appear as either environmental fungi, such as yeasts and molds, and commensal fungi, which live either on or inside the body. Both are typically harmless to most healthy people and can provide some benefits, such as improving gut health, but they may also be a contributing factor in some disease.
The researchers found that there were notable parallels between specific fungi and certain factors, such as age, tumor subtypes, smoking status, immunotherapy responses, and survival measures.
“These findings validate the view that the microbiome in its entirety is a key piece of cancer biology and may present significant translational opportunities, not only in cancer detection, but also in other biotech applications related to drug development, cancer evolution, minimal residual disease, relapse, and companion diagnostics,” said Gregory Sepich-Poore, MD, PhD, one of the study’s authors and co-founder and chief analytics officer at biotechnology company Micronoma, in the UCSD press release.
New Clinical Laboratory Tests to Identify Fungal Species in Cancer
Researchers from Duke University and Cornell University uncovered compelling evidence of fungi in multiple cancer types and focused on a detected link between Candida and gastrointestinal cancers.
They found that “several Candida species were enriched in tumor samples and tumor-associated Candida DNA was predictive of decreased survival,” according to their paper.
Their analysis of multiple body sites revealed tumor-associated mycobiomes in fungal cells. The researchers found that fungal spores known as blastomyces were associated with tumor tissues in lung cancers, and that high rates of Candida were present in stomach and colon cancers.
The Duke/Cornell researchers hope their work can provide a framework to develop new tests that can distinguish fungal species in tumors and predict cancer progression and help medical professionals and patients chose the best treatment therapies.
“These findings open up a lot of exciting research directions, from the development of diagnostics and treatments to studies of the detailed biological mechanisms of fungal relationships to cancers,” said Iliyan Iliev, PhD, Associate Professor of Microbiology and Immunology in Medicine, Weill Cornell Medicine, and one of the authors of the study, in a Weill news release.
More research is needed to determine if fungal DNA plays a role in disease pathology or if its presence does not have any causal link.
“It’s plausible that some of these fungi are promoting tumor progression and metastasis, but even if they aren’t, they could be very valuable as prognostic indicators,” Iliev said.
The insights gleaned from these two studies will be of particular interest to microbiologists, clinical laboratory professionals, and anatomic pathologists. Additional research could answer questions about how and if fungi infect tumors and if such fungi is a factor that increases cancer risk and outcomes.
New discoveries about the genetics of prostate cancer could lead to better tools for diagnosing the disease and selecting effective therapies based on each patient’s specific physiology
In recent decades, the biggest challenge for urologists, and for the pathologists who diagnosed the prostate tissue specimens they referred, has been how to accurately differentiate between non-aggressive prostate cancer, which can exist for decades with no apparent symptoms, and aggressive prostate cancer that kills quickly.
Thus, a research study that has identified unique genetic features within prostate cancer that can help determine if the cancer is aggressive or not, and whether certain drugs may be effective, is good news for men, for urologists, and for the clinical laboratories that will be called upon to perform testing.
These types of breakthroughs bring precision medicine ever closer to having viable tools for effective diagnosis of different types of cancer.
Genetic Fingerprints of Cancer Tumor Types
One such study into the genetic pathways of prostate cancer is bringing precision medicine ever-closer to the anatomic pathology laboratory. Researchers from the Princess Margaret Cancer Centre, which is associated with the University of Toronto Faculty of Medicine, have discovered that some tumors in prostate cancer have a genetic fingerprint that may indicate whether or not the disease will become more aggressive and less responsive to treatment.
Robert Bristow, MD, PhD, and Paul Boutros, PhD, conducted a study of nearly 500 Canadian men who had prostate cancer. Published in the journal Nature, the researchers examined the genetic sequences of those tumors, looking for differences between those that responded to surgery or radiation and those that did not.
In the video above, Dr. Robert Bristow, clinician-scientist at Princess Margaret Cancer Centre, discusses the findings of a key piece in the genetic puzzle that explains why men born with a BRCA2 mutation develop aggressive prostate cancer. (Caption and photo copyright: University Health Network/Princess Margaret Cancer Centre.)
According to a FierceBiotech article, approximately 30% of men who have a type of prostate cancer thought to be curable eventually develop an aggressive metastatic type of the disease. About half of the men who developed a metastatic form of cancer had mutations to three specific genes:
“This information gives us new precision about the treatment response of men with prostate cancer and important clues about how to better treat one set of men versus the other to improve cure rates overall,” stated Bristow in a University Health Network (UHN) press release.
In another study, researchers looked at 15 patients with BRCA2-inheritied prostate cancer and compared the genomic sequences of those tumors to a large group of sequences from tumors in less-aggressive cancer cases. According to a ScienceDaily news release, they found that only 2% of men with prostate cancer have the BRCA2-inherited type.
Knowing what type of cancer a man has could be critically important for clinicians tasked with prescribing the most efficient therapies.
“The pathways that we discovered to be abnormal in the localized BRCA2-associated cancers are usually only found in general population cancers when they become resistant to hormone therapy and spread through the body,” noted Bristow in the ScienceDaily release. If clinicians knew from diagnosis that the cancer is likely to become aggressive, they could choose a more appropriate therapy from the beginning of treatment.
Genetic Mutations Also Could Lead to Breast and Brain Cancer Treatments
BRCA mutations have also been implicated in breast, ovarian, and pancreatic cancers, among some other types. The knowledge that BRCA1 and BRACA2 mutations could indicate a more aggressive cancer is likely to spark investigation into whether poly ADP ribose polymerase (PARP) inhibitors could be used as an effective therapy.
Researchers of the study published in the journal Science Translational Medicine stated that they “demonstrate mutant IDH1-dependent PARP inhibitor sensitivity in a range of clinically relevant models, including primary patient-derived glioma cells in culture and genetically matched tumor xenografts in vivo.”
According to the UHN press release, the next step in using the knowledge that BRCA1 and BRCA2 may indicate a more aggressive prostate cancer is for researchers to create a diagnostic tool that can be used to determine what type of prostate cancer a man has. They expect the process to take several years. “This work really gives us a map to what is going on inside a prostate cancer cell, and will become the scaffold on which precision therapy will be built,” Boutros stated in a Prostate Cancer Canada news release.
Unlocking Knowledge That Leads to Accurate Diagnoses and Treatments
Research that furthers precision medicine and allows clinicians to choose the most appropriate treatment for individuals shows how quickly scientists are applying new discoveries. Every new understanding of metabolic pathways that leads to a new diagnostic tool gives clinicians and the patients they treat more information about the best therapies to select.
For the anatomic pathology profession, this shows how ongoing research into the genetic makeup of prostate cancer is unlocking knowledge about the genetic and metabolic pathways involved in this type of cancer. Not only does this help in diagnosis, but it can guide the selection of appropriate therapies.
On the wider picture, the research at the Princess Margaret Cancer Centre is one more example of how scientists are rapidly applying new knowledge about molecular and genetic processes in the human body to identify new ways to more accurately diagnose disease and select therapies.
Additional studies are needed before medical laboratory tests for ‘lean’ microbes can be developed for use by physicians treating overweight and obese patients
Researchers at Cornell University have identified a family of microbes that may provide a genetic explanation for why some people are able to stay thin. If their findings are validated, a clinical laboratory test for these bacteria, and a macrobotic regiment to help people lose weight or stay lean, could be down the road.
Ruth Ley, Ph.D., is a Cornell University Associate Professor of Microbiology, and the research paper’s senior author. She believes the new Cornell study makes clear the connection between the human genotype and health-associated gut bacteria. (more…)
Newspaper in Rochester, Minnesota, tells the story of how the 19th century use of frozen sections by pathologists at Mayo Clinic played key role in developing intra-operative diagnostics
It’s a good thing for pathologists each time a local newspaper runs a story that highlights the contribution of pathology to the practice of medicine. Since pathologists typically don’t see patients, media stories about the pathologist’s role in diagnosing disease are effective ways to educate consumers.
This was the case when Rochester, Minnesota-based PostBulletin.com recently ran a story about—who else—but the pathology laboratory at the Mayo Clinic. The story highlighted the early development of the frozen section technique (FST) at Mayo Clinic. This newspaper story created community exposure about the role of pathology and pathologists in delivering quality healthcare. (more…)
