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Genetic Tests Are Detecting Prevalence of Bird Flu Virus in US Wastewater and Allowing Officials to Track its Spread

Though PCR clinical laboratory testing is widely used, some scientists are concerned its specificity may limit the ability to identify all variants of bird flu in wastewater

Wastewater testing of infectious agents appears to be here to stay. At the same time, there are differences of opinion about which methodologies and clinical laboratory tests are best suited to screen for specific contagions in wastewater. One such contagion is avian influenza, the virus that causes bird flu.

Wastewater testing by public health officials became a valuable tool during the COVID-19 pandemic and has now become a common method for detecting other diseases as well. For example, earlier this year, scientists used wastewater testing to learn how the H5N1 variant of the bird flu virus was advancing among dairy herds across the country.

In late March, the bird flu was first detected in dairy cattle in Texas, prompting scientists to begin examining wastewater samples to track the virus. Some researchers, however, expressed concerns about the ability of sewage test assays to detect all variants of certain diseases.

“Right now we are using these sort of broad tests to test for influenza A viruses,” Denis Nash, PhD, Distinguished Professor of Epidemiology at City University of New York (CUNY) and Executive Director of CUNY’s Institute for Implementation Science in Population Health (SPH), told the Los Angeles Times. “It’s possible there are some locations around the country where the primers being used in these tests might not work for H5N1.” Clinical laboratory PCR genetic testing is most commonly used to screen for viruses in wastewater. (Photo copyright: CUNY SPH.)

Effectiveness of PCR Wastewater Testing

Polymerase chain reaction (PCR) tests are most commonly used to distinguish genetic material related to a specific illness such as the flu virus. For PCR tests to correctly identify a virus, the tests must be designed to look for a specific subtype. The two most prevalent human influenza A viruses are known as H1N1 (swine flu) and H3N2, which was responsible for the 1968 pandemic that killed a million people worldwide. The “H” stands for hemagglutinin and the “N” for neuraminidase.

Hemagglutinin is a glycoprotein that assists the virus to attach to and infect host cells. Neuraminidase is an enzyme found in many pathogenic or symbiotic microorganisms that separates the links between neuraminic acids in various molecules.

Avian flu is also an influenza A virus, but it has the subtype H5N1. Although human and bird flu viruses both contain the N1 signal, they do not share an H. Some scientists fear that—in cases where a PCR test only looks for H1 and H3 in wastewater—that test could miss the bird flu altogether.

“We don’t have any evidence of that. It does seem like we’re at a broad enough level that we don’t have any evidence that we would not pick up H5,” Jonathan Yoder, Deputy Director, Infectious Disease Readiness and Innovation at the US Centers for Disease Control and Prevention (CDC) told the Los Angeles Times.

The CDC asserts current genetic testing methods are standardized and will detect the bird flu. Yoder also affirmed the tests being used at all the testing sites are the same assay, based on information the CDC has published regarding testing for influenza A viruses. 

Genetic Sequencing Finds H5N1 in Texas Wastewater

In an article published on the preprint server medRxiv titled, “Virome Sequencing Identifies H5N1 Avian Influenza in Wastewater from Nine Cities,” the authors wrote, “using an agnostic, hybrid-capture sequencing approach, we report the detection of H5N1 in wastewater in nine Texas cities, with a total catchment area population in the millions, over a two-month period from March 4th to April 25th, 2024.”

The authors added, “Although human to human transmission is rare, infection has been fatal in nearly half of patients who have contracted the virus in past outbreaks. The increasing presence of the virus in domesticated animals raises substantial concerns that viral adaptation to immunologically naïve humans may result in the next flu pandemic.”

“So, it’s not just targeting one virus—or one of several viruses—as one does with PCR testing,” Eric Boerwinkle, PhD, Dean of the UTHealth Houston School of Public Health told the LA Times. “We’re actually in a very complex mixture, which is wastewater, pulling down viruses and sequencing them. What’s critical here is it’s very specific to H5N1.”

Epidemiologist Blake Hanson, PhD, Assistant Professor, Department of Epidemiology, Human Genetics, and Environmental Sciences at the UT Health Houston Graduate School of Biomedical Science, agreed with Boerwinkle that though the PCR-based methodology is highly effective at detecting avian flu in wastewater samples, the testing can do more.

“We have the ability to look at the representation of the entire genome, not just a marker component of it. And so that has allowed us to look at H5N1, differentiate it from some of our seasonal fluids like H1N1 and H3N2,” Hanson told the LA Times. “It’s what gave us high confidence that it is entirely H5N1, whereas the other papers are using a part of the H5 gene as a marker for H5.”

Human or Animal Sources

Both Boerwinkle and Hanson are epidemiologists in the team studying wastewater samples for H5N1 in Texas. They are not sure where the virus originated but are fairly certain it did not come from humans.

“Texas is really a confluence of a couple of different flyways for migratory birds, and Texas is also an agricultural state, despite having quite large cities,” Boerwinkle noted. “It’s probably correct that if you had to put your dime and gamble what was happening, it’s probably coming from not just one source but from multiple sources. We have no reason to think that one source is more likely any one of those things.”

“Because we are looking at the entirety of the genome, when we look at the single human H5N1 case, the genomic sequence has a hallmark amino acid change, compared to all of the cattle from that same time point,” Hanson said. “We do not see that hallmark amino acid present in any of our sequencing data. And we’ve looked very carefully for that, which gives us some confidence that we’re not seeing human-human transmission.”

CDC Updates on Bird Flu

In its weekly updates on the bird flu situation, the CDC reported that 48 states have outbreaks in poultry and 14 states have avian flu outbreaks in dairy cows. More than 238 dairy herds have been affected and, as of September 20, over 100 million poultry have been affected by the disease.

In addition, the CDC monitored more than 4,900 people who came into contact with an infected animal. Though about 230 of those individuals have been tested for the disease, there have only been a total of 14 reported human cases in the US.

The CDC posts information specifically for laboratory workers, healthcare providers, and veterinarians on its website.

The CDC also states that the threat from avian flu to the general public is low. Individuals at an increased risk for infection include people who work around infected animals and those who consume products containing raw, unpasteurized cow’s milk.

Symptoms of H5N1 in humans may include fever or chills, cough, headaches, muscle or body aches, runny or stuffy nose, tiredness and shortness of breath. Symptoms typically surface two to eight days after exposure.

Scientists and researchers have been seeking a reliable clinical laboratory test for disease organisms in a fast, accurate, and cost-effective manner. Wastewater testing of infectious agents could fulfill those goals and appears to be a technology that will continue to be used for tracking disease.

—JP Schlingman

Related Information:

As National Wastewater Testing Expands, Texas Researchers Identify Bird Flu in Nine Cities

Experts Blast CDC over Failure to Test Sewage for Signs of H5N1 Bird Flu Virus

From Sewage to Safety: Hospital Wastewater Surveillance as a Beacon for Defense Against H5N1 Bird Flu

The Bird Flu Outbreak Has Spread to Humans: Are We Too Late to Prevent the Next Pandemic?

Detection of Hemagglutinin H5 Influenza A Virus Sequence in Municipal Wastewater Solids at Wastewater Treatment Plants with Increases in Influenza A in Spring, 2024

Virome Sequencing Identifies H5N1 Avian Influenza in Wastewater from Nine Cities

Wastewater Analysis Continues to Be an Effective Tool for Tracking Deadly Infectious Diseases in Human Communities

Genetic Testing of Wastewater Now Common in Detecting New Strains of COVID-19 and Other Infectious Diseases

San Francisco International Airport First in the Nation to Test Wastewater for SARS-CoV-2 Coronavirus

New, Cryptic COVID-19 Lineage Found in Ohio Wastewater by Molecular Virologist Tracking Spread of SARS-CoV-2 Variants

National Institutes of Health Study Finds No Reliable Biomarkers Exist for Long COVID

Study is another example of how important clinical laboratory testing is when government officials attack a new public health issue

Long COVID—aka SARS-CoV-2 infection’s post-acute sequelae (PASC)—continues to confound researchers seeking one or more clinical laboratory biomarkers for diagnosing the condition. A new study led by the National Institutes of Health’s (NIH) RECOVER Initiative and supported by NYU Langone Health recently revealed that “routine clinical laboratory tests were unable to provide a reliable biomarker of … long COVID,” Inside Precision Medicine reported.

The NIH’s Researching COVID to Enhance Recovery (RECOVER) Initiative used a cohort study of more than 10,000 individuals with and without previous COVID-19 diagnoses and compared samples using 25 common laboratory tests in hopes a useful biomarker could be identified. They were unsuccessful.

Leora Horwitz, MD, director of the Center for Healthcare Innovation and Delivery Science and co-principal investigator for the RECOVER CSC (Clinical Science Core) at NYU Langone; Andrea S. Foulkes, ScD, director of biostatistics at Massachusetts General Hospital, Boston; and Grace A. McComsey, MD, VP of research and associate chief scientific officer at University Hospitals Health System, and professor of pediatrics and medicine at Case Western Reserve University, led the study.

Long COVID—or PASC—is an umbrella term for those with persistent post-COVID infection symptoms that negatively impact quality of life. Though it affects millions worldwide and has been called a major public health burden, the NIH/Langone study scientists noted one glaring problem: PASC is defined differently in the major tests they studied. This makes consistent diagnoses difficult.

The study brought to light possible roadblocks that prevented biomarker identification.

“Although potential models of pathogenesis have been postulated, including immune dysregulation, viral persistence, organ injury, endothelial dysfunction, and gut dysbiosis, there are currently no validated clinical biomarkers of PASC,” the study authors wrote in their study, “Differentiation of Prior SARS-CoV-2 Infection and Postacute Sequelae by Standard Clinical Laboratory Measurements in the RECOVER Cohort,” published in the journal Annals of Internal Medicine.

“This study is an important step toward defining long COVID beyond any one individual symptom,” said study author Leora Horwitz, MD (above), director of the Center for Healthcare Innovation and Delivery Science and co-principal investigator for the RECOVER CSC at NYU Langone, in a Langone Health news release. “This definition—which may evolve over time—will serve as a critical foundation for scientific discovery and treatment design.” In the future, clinical laboratories may be tasked with finding combinations of routine and reference tests that, together, enable a more precise and earlier diagnosis of long COVID.  (Photo copyright: Yale School of Medicine.)

NIH/Langone Study Details

“The study … examined 25 routinely used and standardized laboratory tests chosen based on availability across institutions, prior literature, and clinical experience. These tests were conducted prospectively in laboratories that are certified by the Clinical Laboratory Improvement Amendments (CLIA). The samples were collected from 10,094 RECOVER-Adult participants, representing a diverse cohort from all over the US,” Inside Precision Medicine reported.

However, the scientists found no clinical laboratory “value” among the 25 tests examined that “reliably indicate previous infection, PASC, or the particular cluster type of PASC,” Inside Precision Medicine noted, adding that “Although some minor differences in the results of specific laboratory tests attempted to differentiate between individuals with and without a history of infection, these findings were generally clinically meaningless.”

“In a cohort study of more than 10,000 participants with and without prior SARS-CoV-2 infection, we found no evidence that any of 25 routine clinical laboratory values provide a reliable biomarker of prior infection, PASC, or the specific type of PASC cluster. … Overall, no evidence was found that any of the 25 routine clinical laboratory values assessed in this study could serve as a clinically useful biomarker of PASC,” the study authors wrote in Annals of Internal Medicine.

In addition to a vague definition of PASC, the NIH/Langone researchers noted a few other potential problems identifying a biomarker from the research.

“Use of only selected biomarkers, choice of comparison groups, if any (people who have recovered from PASC or healthy control participants); duration of symptoms; types of symptoms or phenotypes; and patient population features, such as sex, age, race, vaccination status, comorbidities, and severity of initial infection,” could be a cause for ambiguous results, the scientists wrote.

Future Research

“Understanding the basic biological underpinnings of persistent symptoms after SARS-CoV-2 infection will likely require a rigorous focus on investigations beyond routine clinical laboratory studies (for example, transcriptomics, proteomics, metabolomics) to identify novel biomarkers,” the study authors wrote in Annals of Internal Medicine.

“Our challenge is to discover biomarkers that can help us quickly and accurately diagnose long COVID to ensure people struggling with this disease receive the most appropriate care as soon as possible,” said David Goff, MD, PhD, director of the division of cardiovascular sciences at the NIH’s National Heart, Lung, and Blood Institute, in an NHLBI news release. “Long COVID symptoms can prevent someone from returning to work or school, and may even make everyday tasks a burden, so the ability for rapid diagnosis is key.”

“Approximately one in 20 US adults reported persisting symptoms after COVID-19 in June 2024, with 1.4% reporting significant limitations,” the NIH/Langone scientists wrote in their published study.

Astute clinical laboratory scientists will recognize this as possible future diagnostic testing. There is no shortage of need.

—Kristin Althea O’Connor

Related Information:

“Long COVID” Evades Common SARS-CoV-2 Clinical Lab Tests

Differentiation of Prior SARS-CoV-2 Infection and Postacute Sequelae by Standard Clinical Laboratory Measurements in the RECOVER Cohort

Long COVID Diagnostics: An Unconquered Challenge

RECOVER Study Offers Expanded Working Definition of Long COVID

Routine Lab Tests Are Not a Reliable Way to Diagnose Long COVID

Broad Institute of MIT and Harvard Studies Use of Polygenic Risk Scores to Evaluate Genetic Risk for 10 Diseases

Though not biomarkers per se, these scores for certain genetic traits may someday be used by clinical laboratories to identify individuals’ risk for specific diseases

Can polygenic risk scores (a number that denotes a person’s genetic predisposition for certain traits) do a better job at predicting the likelihood of developing specific diseases, perhaps even before the onset of symptoms? Researchers at the Broad Institute of MIT and Harvard (Broad Institute) believe so, and their study could have implications for clinical laboratories nationwide.

In cooperation with medical centers across the US, the scientists “optimized 10 polygenic scores for use in clinical research as part of a study on how to implement genetic risk prediction for patients,” according to a Broad Institute news release.

The research team “selected, optimized, and validated the tests for 10 common diseases [selected from a total of 23 conditions], including heart disease, breast cancer, and type 2 diabetes. They also calibrated the tests for use in people with non-European ancestries,” the news release notes.

As these markers for genetic risk become better understood they may work their way into clinical practice. This could mean clinical laboratories will have a role in sequencing patients’ DNA to provide physicians with information about the probability of a patient’s elevated genetic risk for certain conditions.

However, the effectiveness of polygenic risk scores has faced challenges among diverse populations, according to the news release, which also noted a need to appropriately guide clinicians in use of the scores.

The researchers published their study, “Selection, Optimization and Validation of 10 Chronic Disease Polygenic Risk Scores for Clinical Implementation in Diverse US Populations,” in Nature Medicine.

“With this work, we’ve taken the first steps toward showing the potential strength and power of these scores across a diverse population,” said Niall Lennon, PhD (above), Chief Scientific Officer of Broad Clinical Labs.  “We hope in the future this kind of information can be used in preventive medicine to help people take actions that lower their risk of disease.” Clinical laboratories may eventually be tasked with performing DNA sequencing to determine potential genetic risk for certain diseases. (Photo copyright: Broad Institute.)

Polygenic Scores Need to Reflect Diversity

“There have been a lot of ongoing conversations and debates about polygenic risk scores and their utility and applicability in the clinical setting,” said Niall Lennon, PhD, Chair and Chief Scientific Officer of Broad Clinical Labs and first author of the study, in the news release. However, he added, “It was important that we weren’t giving people results that they couldn’t do anything about.”

In the paper, Lennon and colleagues explained polygenic risk scores “aggregate the effects of many genetic risk variants” to identify a person’s genetic predisposition for a certain disease or phenotype.

“But their development and application to clinical care, particularly among ancestrally diverse individuals, present substantial challenges,” they noted. “Clinical use of polygenic risk scores may ultimately prevent disease or enable its detection at earlier, more treatable stages.” 

The scientists set a research goal to “optimize polygenic risk scores for a diversity of people.”

They collaborated with the Electronic Medical Records and Genomics network (eMERGE) and 10 academic medical centers that enrolled 25,000 participants in the eMERGE study. Funded by the National Human Genome Research Institute of the National Institutes of Health (NIH), the eMERGE network conducts genetic research in support of genetic medicine. 

While performing the polygenic risk score testing on participants, Broad Clinical Labs focused on 10 conditions—including cardiometabolic diseases and cancer—selected by the research team based on “polygenic risk score performance, medical actionability, and clinical utility,” the Nature Medicine paper explained. 

For each condition, the researchers:

  • Identified “exact spots in the genome that they would analyze to calculate the risk score.”
  • Verified accurate genotyping of the spots by comparing results of tests with whole genome sequences from patient blood samples.
  • Used information from the NIH’s All of Us Research Program to “create a model to calibrate a person’s polygenic risk score according to that individual’s genetic ancestry.”

The All of Us program, which aims to collect health information from one million US residents, has three times more people of non-European ancestry than other data sources developing genetic risk scores, HealthDay News reported.

20% of Study Participants Showed High Risk for Disease

To complete their studies, Broad Institute researchers processed a diverse group of eMERGE participants to determine their clinical polygenic risk scores for each of the 10 diseases between July 2022 and August 2023.

Listed below are all conditions studied, as well as the number of participants involved in each study and the number of people with scores indicating high risk of the disease, according to their published paper:

Over 500 people (about 20%) of the 2,500 participants, had high risk for at least one of the 10 targeted diseases, the study found. 

Participants in the study self-reported their race/ancestry as follows, according to the paper:

  • White: 32.8%
  • Black: 32.8%
  • Hispanic: 25.4%
  • Asian: 5%
  • American Indian: 1.5%
  • Middle Eastern: 0.9%
  • No selection: 0.8%

“We can’t fix all biases in the risk scores, but we can make sure that if a person is in a high-risk group for a disease, they’ll get identified as high risk regardless of what their genetic ancestry is,” Lennon said.

Further Studies, Scoring Implications

With 10 tests in hand, Broad Clinical Labs plans to calculate risk scores for all 25,000 people in the eMERGE network. The researchers also aim to conduct follow-up studies to discover what role polygenic risk scores may play in patients’ overall healthcare.

“Ultimately, the network wants to know what it means for a person to receive information that says they’re at high risk for one of these diseases,” Lennon said.

The researchers’ findings about disease risk are likely also relevant to healthcare systems, which want care teams to make earlier, pre-symptomatic diagnosis to keep patients healthy.

Clinical laboratory leaders may want to follow Broad Clinical Labs’ studies as they perform the 10 genetic tests and capture information about what participants may be willing to do—based on risk scores—to lower their risk for deadly diseases.

—Donna Marie Pocius

Related Information:

Genetic Risk Prediction for 10 Chronic Diseases Moves Closer to the Clinic

Selection, Optimization, and Validation of 10 Chronic Disease Polygenic Risk Scores for Clinical Implementation in Diverse US Populations

Gene-Based Tests Could Predict Your Odds for Common Illnesses

South Korean Study Finds Fecal Microbiota Transplants May Help Patients with Gastrointestinal Cancers That are Resistant to Immunotherapies

Study findings could lead to improved treatments for broad range of cancers and the need for microbiome testing by clinical laboratories to guide clinicians

Is it possible that there is a connection between an individual’s gut microbiota and the ability to fight off gastrointestinal (GI) cancer? Findings from a preliminary research study performed by researchers in South Korea suggest that a link between the two may exist and that fecal microbiota transplants (FMTs) may enhance the efficacy of immunotherapies for GI cancer patients. 

The proof-of-concept clinical trial, conducted at the Gwangju Institute of Science and Technology (GIST), Gwangju 61005, Republic of Korea, analyzed how an FMT could help 13 patients with metastatic solid tumors that were resistant to the anti-PD-1 antibody drug known as nivolumab (Opdivo). Anti-PD-1 drugs are immunotherapies that help treat cancer by improving an individual’s immune response against cancer cells. 

Four of the trial participants had gastric cancer, five had esophageal cancer, and the remaining four had hepatocellular carcinoma. The patients were given a colonoscopy to implant the FMTs. The recipients also received antibiotics to reduce the response of their existing microbiotas.

The FMT donors also had gastric cancer, esophageal cancer, or hepatocellular carcinoma. Prior to donating their fecal matter, the donors experienced complete or partial response to the anti-PD-1 drugs nivolumab or pembrolizumab (Keytruda) for at least six months after receiving initial treatments. 

The researchers published their study, titled, “Fecal Microbiota Transplantation Improves Anti-PD-1 Inhibitor Efficacy in Unresectable or Metastatic Solid Cancers Refractory to Anti-PD-1 Inhibitor,” in the journal Cell Host and Microbe.

“This research highlights the complex interplay between beneficial and detrimental bacteria within the gut microbiota in determining treatment outcomes,” co-senior study author Hansoo Park, MD, PhD, Assistant Professor, Biomedical Science and Engineering, Gwangju Institute of Science and Technology, told The ASCO Post. “While the connection between gut microbiota and immune response to cancer therapy has been a growing area of interest, our study provides concrete evidence and new avenues for improving treatment outcomes in a broader range of cancers,” he added. Further studies may confirm the need for microbiome testing by clinical laboratories to guide clinicians treating patients with colon cancers. (Photo copyright: Gwangju Institute of Science and Technology.)

Surprising Results

Fecal material for an FMT procedure combines donated fecal matter with a sterile saline solution which is then filtered to produce a liquid solution. That solution is then administered to the recipient via colonoscopy, upper GI endoscopy, enema, or an oral capsule. The solution may also be frozen for later use.

Upon analyzing the recipients, the scientists found that six of the patients (46.2%) who had experienced resistance to immunotherapies for their cancers, benefitted from the FMTs.

“One of the most surprising results was from a [patient with] hepatocellular carcinoma who initially showed no response to the first [FMT] and continued to experience cancer progression. However, after switching the donor for the second [transplant], the patient exhibited remarkable tumor shrinkage,” co-senior study author Sook Ryun Park, MD, PhD, Assistant Professor, Asan Medical Center at the University of Ulsan College of Medicine in Seoul, told The ASCO Post, a journal of the American Society of Clinical Oncology.

“Both donors were long-lasting, good responders to anti-PD-1 inhibitors, but because we did not yet know the causative bacteria responsible for the [FMT] response, we could not predict whether the treatment would be effective,” she added.

The researchers also determined that the presence of a bacterial strain known as Prevotella merdae helped to improve the effectiveness of the FMTs, while two strains of bacteria—Lactobacillus salivarius and Bacteroides plebeius (aka, Phocaeicola plebeius)—had a detrimental impact on the transplants. 

Challenges to Widespread Adoption of FMTs

The researchers acknowledge there are challenges in widespread acceptance and use of FMTs in treating cancers but remain optimistic about the possibilities.

“Developing efficient and cost-effective methods for production and distribution is necessary for widespread adoption,” Sook Ryun Park told The ASCO Post. “Addressing these challenges through comprehensive research and careful planning will be essential for integrating FMT into the standard of care for cancer treatment.”

The research for this study was supported by grants from the Asan Institute for Life Sciences, Asan Medical Center, National Cancer Centre in Korea, the GIST Research Institute, the Bio and Medical Technology Development Program from Ministry of Science, and the Ministry of Science and ICT of the South Korean Government.

More research and clinical trials are needed before this use of FMTs can be utilized in clinical settings. However, the study does demonstrate that the potential benefits of FMTs may improve outcomes in patients with certain cancers. As this happens, microbiologists may gain a new role in analyzing the microbiomes of patients with gastrointestinal cancers.

“By examining the complex interactions within the microbiome, we hope to identify optimal microbial communities that can be used to enhance cancer treatment outcomes,” Hansoo Park told The ASCO Post. “This comprehensive approach will help us understand how the microbial ecosystem as a whole contributes to therapeutic success.”

—JP Schlingman

Related Information:

Fecal Microbiota Transplant May Help Patients with Gastrointestinal Cancers Overcome Immunotherapy Resistance

Fecal Microbiota Transplantation Improves Anti-PD-1 Inhibitor Efficacy in Unresectable or Metastatic Solid Cancers Refractory to Anti-PD-1 Inhibitor

Fecal Microbiota Transplants Can Boost the Effectiveness of Immunotherapy in Gastrointestinal Cancers

Texas Researchers Find ‘Acid Walls’ That Shield Cancer Tumors from Body’s Immune System Response

Discovery could lead to new  treatments for cancer and tumors, but probably not to any new diagnostic assays for clinical laboratories

Researchers at the University of Texas Southwestern (UTSW) Medical Center have reported discovery of “acid walls” that appear to protect various types of cancer tumors from attack by the body’s immune system cells. Though the discovery is not directly related to a biomarker for a clinical laboratory diagnostic test, the basic research will help scientists develop ways to address the tumor’s acid wall strategy for defeating the immune system.

The UT scientists made their discovery using an internally developed imaging technique that employs nanoparticle probes to detect levels of acidity in cells. The research, they suggest, “could pave the way for new cancer treatment approaches that alter the acidic environment around tumors,” according to a UTSW press release.

Study leader Jinming Gao, PhD, Professor in the Harold C. Simmons Comprehensive Cancer Center and in the Departments of Biomedical Engineering, Cell Biology, Otolaryngology-Head and Neck Surgery, and Pharmacology at UT Southwestern, leads the Gao Lab which developed the nanoparticle technology.

The researchers published their study, titled “Severely Polarized Extracellular Acidity around Tumour Cells,” in the journal Nature Biomedical Engineering.

“This study revealed a previously unrecognized polarized extracellular acidity that is prevalent around cancer cells,” said lead study author Jinming Gao, PhD (above), Professor in the Harold C. Simmons Comprehensive Cancer Center and head of the Gao Lab at UT Southwestern Medical Center, in a press release. Gao believes the study “will lead to several new lines of research, such as studies to better understand how cancer cells polarize their acid excretion, how those cells can withstand the acidity level that kills CD8+ T cells, and how to inhibit acid excretion to allow T cells to better kill cancer cells,” the press release notes. (Photo copyright: University of Texas.)

Developing Acid Walls

As explained in the press release, scientists have long known that cancer cells are slightly more acidic than most healthy tissue. Gao and his team designed a nanoparticle known as pegsitacianine—a pH-sensitive fluorescent nanoprobe for image-guided cancer surgery—that disassembles and lights up when exposed to the acidic conditions in tumors.

However, “it was unclear why these nanoparticles fluoresced since a tumor’s acidity was thought to be too mild to trigger their activation,” the press release note.

To learn more, they used nanoparticle probes to illuminate a variety of individual cancer cells sampled from humans and mice, including lung, breast, melanoma, and glioblastoma, as well as tumor tissue. They discovered that the cancer cells secreted lactic acid—a waste product of digested glucose—at higher levels than previously known. The cells “pumped” the acid away from their malignant neighbors to form a protective “acid wall” around the tumor, the researchers noted in Nature Biomedical Engineering.

“Samples from human tumors showed that this acid wall was practically devoid of CD8+ T cells within the tumors, an immune cell type known to fight cancer,” the press release states. “When the researchers grew cancer cells and CD8+ T cells together in petri dishes that had been acidified to a 5.3 pH, the cancer cells were spared while the CD8+ T cells perished within three hours, suggesting that this severe acidity might thwart immune cell attack without harming the cancer cells.”

Gao’s team previously discovered that sodium lactate, the “conjugate base of lactic acid” as they describe it, increases the longevity of T cells and thus enhances their cancer-fighting capabilities. The researchers described the two molecules—lactate and lactic acid—as “Dr. Jekyll and Mr. Hyde,” and suggested that future therapies could seek to convert lactic acid to lactate.

“Gao noted that this discovery will lead to several new lines of research, such as studies to better understand how cancer cells polarize their acid excretion, how those cells can withstand the acidity level that kills CD8+ T cells, and how to inhibit acid excretion to allow T cells to better kill cancer cells,” the press release states.

Commercializing the Technology

Pegsitacianine was designed to aid cancer surgeons by illuminating the edges of solid metastatic tumors in real time during surgery, a 2023 UTSW Medical Center press release explains. About 24 hours prior to surgery, nanoprobes are delivered via IV. Then, the surgeon uses a near-infrared camera to visualize the cells.

UTSW has licensed pegsitacianine to OncoNano Medicine, a Dallas-area biotech startup launched to commercialize technologies from Gao Lab. Gao and his colleague Baran Sumer, MD, Professor and Chief of the Division of Head and Neck Oncology in UT Southwestern Medical Center’s Department of Otolaryngology and co-author on the study, both sit on OncoNano’s advisory board.

In January 2023, OncoNano announced that pegsitacianine had received Breakthrough Therapy Designation for Real-Time Surgical Imaging from the US Food and Drug Administration (FDA), which will fast-track the technology for development and regulatory review.

In a Phase II clinical trial published in the Annals of Surgical Oncology, the researchers tested the technology as part of cytoreductive surgery in patients with peritoneal metastases. However, a November 2023 UTSW press release noted that the technology is “tumor-agnostic and could potentially be used in other forms of cancer.” It is currently ready for Phase 3 trials, according to the OncoNano website.

More research and studies are needed to better understand this dynamic of cancer cells. Collectively, this research into cancer by different scientific teams is adding new insights into the way tumors originate and spread. At this time, these insights are not expected to lead to any new diagnostics tests that pathologists and clinical laboratories could use to detect cancer.

—Stephen Beale

Related Information:

UTSW Discovers Protective ‘Acid Wall’ Formed by Cancer Cells

Scientists Discover How Cancer Creates ‘Acid Wall’ Against Immune System

Severely Polarized Extracellular Acidity around Tumour Cells

Fluorescent Nanoprobe Produces ‘Breakthrough’ for Peritoneal Metastases

Pegsitacianine Informs Surgery in Peritoneal Carcinomatosis

Lancet Study Finds Urgent Need for Improvement in Clinical Laboratory Prostate Cancer Screening Worldwide

Ongoing increases in the global number of prostate cancer cases expected to motivate test developers to deliver better screening tests to pathologists and clinical lab scientists

No less an authority than the peer-reviewed healthcare journal The Lancet is drawing attention to predictions of increasing prostate cancer cases across the globe, triggering calls for the development of cheaper, faster, and more accurate assays that pathologists and medical laboratories can use to screen for—and diagnose—prostate cancer.

Swift population growth and rising life expectancy will cause the prostate cancer death rate to nearly double in the next 20 years, according to a new study that has led scientists to call for immediate, critical improvements in clinical laboratory testing for cancer screening, Financial Times (FT) reported.

The International Agency for Research on Cancer (IARC) partnered with The Lancet Commission for the study. They found the strongest need is with underserved populations.

“Low- and middle-income countries need to prepare to prevent a sharp rise in fatalities while richer nations should pay more attention to young men at higher risk of the disease,” FT noted. The study, titled, “The Lancet Commission on Prostate Cancer: Planning for the Surge in Cases,” predicts cases will jump from 1.4 million in 2020 to 2.9 million by 2040.

“Prostate cancer is the most common cancer in men in 112 countries, and accounts for 15% of cancers. In this Commission, we report projections of prostate cancer cases in 2040 on the basis of data for demographic changes worldwide and rising life expectancy. … This surge in cases cannot be prevented by lifestyle changes or public health interventions alone, and governments need to prepare strategies to deal with it,” the study authors wrote.

“The findings in this Commission provide a pathway forward for healthcare providers and funders, public health bodies, research funders, governments, and the broader patient and clinical community,” the authors noted. In their Lancet paper, the researchers define clear areas for improvement.

Given the shortage worldwide of pathologists—especially highly-trained pathologists—the gap between the demand/need for expanded prostate cancer testing as screens (along with prostate biopsies) and the available supply of pathologists will encourage companies to develop screening and diagnostic tests that are accurate and automated, thus increasing the productivity of the available pathologists.

“As more and more men around the world live to middle and old age, there will be an inevitable rise in the number of prostate cancer cases. We know this surge in cases is coming, so we need to start planning and take action now,” said Nick James, PhD (above), Professor of Prostate and Bladder Cancer Research at The Institute of Cancer Research, in a press release. Pathologists and medical laboratories worldwide will want to monitor progress of The Lancet Commission’s recommendations. (Photo copyright: Institute of Cancer Research.)

Focus on Outreach, AI, Research/Development

“The only thing you can do to mitigate the damage … is to set up programs that diagnose it earlier to allow earlier treatment,” Nick James, PhD, The Lancet Commission study’s lead author, told the Financial Times. James is Professor of Prostate and Bladder Cancer Research at The Institute of Cancer Research (IRC) and The Royal Marsden NHS Foundation Trust, London.

“Evidence-based interventions, such as improved early detection and education programs, will help to save lives and prevent ill health from prostate cancer in the years to come. This is especially true for low- and middle-income countries (LMICs) which will bear the overwhelming brunt of future cases,” he said in a press release.

Communication is key. “Improved outreach programs are needed to better inform people of the key signs to look out for and what to do next,” James N’Dow, MD, Professor and Chair in Surgery and Director of the Academic Urology Unit at the University of Aberdeen in the UK, told the Financial Times. “Implementing these in tandem with investments in cost-effective early diagnostic systems will be key to preventing deaths,” he added.

Capitalizing on artificial intelligence (AI) analysis to help translate results was another area The Lancet Commission researchers focused on, Financial Times noted.

AI could “subdivide disease into potentially valuable additional subgroups to help with treatment selection. In environments with few or no pathologists, these changes could be transformational,” the study authors wrote.

High Income Countries (HICs) would benefit from AI by empowering patients. “Linking cloud-based records to artificial intelligence systems could allow access to context-sensitive, up-to-date advice for both patients and health professionals, and could be used to drive evidence-based change in all settings,” the study authors added. Such a trend could lead to specialist prostate cancer pathologists being referred cases from around the world as digital pathology systems become faster and less expensive.

Effective treatment strategies and bolstering areas of need is also key, the study notes. “Many LMICs have urgent need for expansion of radiotherapy and surgery services,” the study authors wrote. The researchers stress the need to immediately implement expansion programs to keep up with anticipated near-future demand.

Cancer drug therapy should follow suit.

“Research and the development of risk-stratified regulatory models need to be facilitated,” the study authors noted, citing a focus on drug repurposing and dose de-escalation. “Novel clinical trial designs, such as multi-arm platforms, should be supported and expanded,” they added.

Unique Needs of LMICs, HICs

The Lancet Commission researchers’ recommendations shift depending on the financial health of a specific area. HICs are experiencing a 30-year decline in the number of deaths resulting from prostate cancer, presumably from additional testing measures and public health campaigns that may be lacking in LMICs, Financial Times reported. And as population growth soars, low-to-middle income populations “will need to be prepared for the strain the expected surge in cases will put on health resources.”

For HICs, the study dissected the limitations of prostate-specific antigen (PSA) testing. The researchers pointed out that PSA’s inaccuracies in screening symptomless patients can pinpoint “cancers that may never cause symptoms and need no treatment,” Financial Times reported.

Missing high-risk cases was also a cause for concern. “Diagnostic pathways should be modified to facilitate early detection of prostate cancer while avoiding overdiagnosis and overtreatment of trivial disease,” the study notes.

Screenings for high-risk younger men, and continuing public campaigns about prostate cancer, should be a focus for HICs, the study authors noted. “These would include people who have a family history of the disease, are of African ancestry, or carry a genetic mutation known as BRCA2,” Financial Times reported.

While the undertaking may sound intimidating—there is already such a heavy impact worldwide from prostate cancer—the researchers are optimistic of their recommendations.

“Options to improve care are already available at moderate cost. We found that late diagnosis is widespread worldwide, but especially in LMICs, where it is the norm. Early diagnosis improves prognosis and outcomes, and reduces societal and individual costs, and we recommend changes to the diagnostic pathway that can be immediately implemented,” the study authors wrote.

What Comes Next

“More research is needed among various ethnic groups to expand understanding of prostate cancer beyond the findings from studies that were largely based on data from white men,” The Lancet Commission told the Financial Times.

Astute pathologists and medical laboratories will want to monitor efforts to develop assays that are inexpensive, more accurate, and produce faster answers. Demand for these tests will be substantial—both in developed and developing nations.

—Kristin Althea O’Connor

Related Information:

Prostate Cancer Rise Sparks Call for Overhaul of Testing

The Lancet Commission on Prostate Cancer: Planning for the Surge in Cases

Lancet Commission Predicts Sharp Increase in Global Prostate Cancer Cases

The Lancet: Prostate Cancer Cases Expected to Double Worldwide Between 2020 and 2040, New Analysis Suggests

Prostate Cancer Cases Might Rise to 3 Million Globally by 2040

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