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Scientists Close in on Elusive Goal of Adapting Nanopore Technology for Protein Sequencing

Technology could enable medical laboratories to deploy inexpensive protein sequencing with a handheld device at point of care and remote locations

Clinical laboratories engaged in protein testing will be interested in several recent studies that suggest scientists may be close to adapting nanopore-sensing technology for use in protein identification and sequencing. The new proteomics techniques could lead to new handheld devices capable of genetic sequencing of proteins at low cost and with a high degree of sensitivity, in contrast to current approaches based on mass spectrometry.

But there are challenges to overcome, not the least of which is getting the proteins to cooperate. Compact devices based on nanopore technology already exist that can sequence DNA and RNA. But “there are lots of challenges with proteins” that have made it difficult to adapt the technology, Aleksei Aksimentiev, PhD, Professor of Biological Physics at the University of Illinois at Urbana-Champaign, told ASBMB Today, a publication of the American Society for Biochemistry and Molecular Biology. “In particular, they’re not uniformly charged; they’re not linear, most of the time they’re folded; and there are 20 amino acids, plus a zoo of post-translational modifications,” he added.

The ASBMB story notes that nanopore technology depends on differences in charges on either side of the membrane to force DNA or RNA through the hole. This is one reason why proteins pose such a challenge.

Giovanni Maglia, PhD, a Full Professor at the University of Groningen in the Netherlands and researcher into the fundamental properties of membrane proteins and their applications in nanobiotechnology, says he has developed a technique that overcomes these challenges.

“Think of a cell as a miniature city, with proteins as its inhabitants. Each protein-resident has a unique identity, its own characteristics, and function. If there was a database cataloging the fingerprints, job profiles, and talents of the city’s inhabitants, such a database would undoubtedly be invaluable!” said Behzad Mehrafrooz, PhD (above), Graduate Research Assistant at University of Illinois at Urbana-Champaign in an article he penned for the university website. This research should be of interest to the many clinical laboratories that do protein testing. (Photo copyright: University of Illinois.)

How the Maglia Process Works

In a Groningen University news story, Maglia said protein is “like cooked spaghetti. These long strands want to be disorganized. They do not want to be pushed through this tiny hole.”

His technique, developed in collaboration with researchers at the University of Rome Tor Vergata, uses electrically charged ions to drag the protein through the hole.

“We didn’t know whether the flow would be strong enough,” Maglia stated in the news story. “Furthermore, these ions want to move both ways, but by attaching a lot of charge on the nanopore itself, we were able to make it directional.”

The researchers tested the technology on what Maglia described as a “difficult protein” with many negative charges that would tend to make it resistant to flow.

“Previously, only easy-to-thread proteins were analyzed,” he said in the news story. “But we gave ourselves one of the most difficult proteins as a test. And it worked!”

Maglia now says that he intends to commercialize the technology through a new startup called Portal Biotech.

The Groningen University scientists published their findings in the journal Nature Biotechnology, titled “Translocation of Linearized Full-Length Proteins through an Engineered Nanopore under Opposing Electrophoretic Force.”

Detecting Post-Translational Modifications in the UK

In another recent study, researchers at the University of Oxford reported that they have adapted nanopore technology to detect post-translational modifications (PTMs) in protein chains. The term refers to changes made to proteins after they have been transcribed from DNA, explained an Oxford news story.

“The ability to pinpoint and identify post-translational modifications and other protein variations at the single-molecule level holds immense promise for advancing our understanding of cellular functions and molecular interactions,” said contributing author Hagan Bayley, PhD, Professor of Chemical Biology at University of Oxford, in the news story. “It may also open new avenues for personalized medicine, diagnostics, and therapeutic interventions.”

Bayley is the founder of Oxford Nanopore Technologies, a genetic sequencing company in the UK that develops and markets nanopore sequencing products.

The news story notes that the new technique could be integrated into existing nanopore sequencing devices. “This could facilitate point-of-care diagnostics, enabling the personalized detection of specific protein variants associated with diseases including cancer and neurodegenerative disorders,” the story states.

The Oxford researchers published their study’s findings in the journal Nature Nanotechnology titled, “Enzyme-less Nanopore Detection of Post-Translational Modifications within Long Polypeptides.”

Promise of Nanopore Protein Sequencing Technology

In another recent study, researchers at the University of Washington reported that they have developed their own method for protein sequencing with nanopore technology.

“We hacked the [Oxford Nanopore] sequencer to read amino acids and PTMs along protein strands,” wrote Keisuke Motone, PhD, one of the study authors in a post on X (formerly Twitter) following the study’s publication on the preprint server bioRxiv titled, “Multi-Pass, Single-Molecule Nanopore Reading of Long Protein Strands with Single-Amino Acid Sensitivity.”

“This opens up the possibility for barcode sequencing at the protein level for highly multiplexed assays, PTM monitoring, and protein identification!” Motone wrote.

In a commentary they penned for Nature Methods titled, “Not If But When Nanopore Protein Sequencing Meets Single-Cell Proteomics,” Motone and colleague Jeff Nivala, PhD, Principal Investigator at University of Washington, pointed to the promise of the technology.

Single-cell proteomics, enabled by nanopore protein sequencing technology, “could provide higher sensitivity and wider throughput, digital quantification, and novel data modalities compared to the current gold standard of protein MS [mass spectrometry],” they wrote. “The accessibility of these tools to a broader range of researchers and clinicians is also expected to increase with simpler instrumentation, less expertise needed, and lower costs.”

There are approximately 20,000 human genes. However, there are many more proteins. Thus, there is strong interest in understanding the human proteome and the role it plays in health and disease.

Technology that makes protein testing faster, more accurate, and less costly—especially with a handheld analyzer—would be a boon to the study of proteomics. And it would give clinical laboratories new diagnostic tools and bring some of that testing to point-of-care settings like doctor’s offices.

—Stephen Beale

Related Information:

Nanopores as the Missing Link to Next Generation Protein Sequencing

Nanopore Technology Achieves Breakthrough in Protein Variant Detection

The Scramble for Protein Nanopore Sequencing

The Emerging Landscape of Single-Molecule Protein Sequencing Technologies

ASU Researcher Advances the Science of Protein Sequencing with NIH Innovator Award          

The Missing Link to Make Easy Protein Sequencing Possible?

Engineered Nanopore Translocates Full Length Proteins

Not If But When Nanopore Protein Sequencing Meets Single-Cell Proteomics

Enzyme-Less Nanopore Detection of Post-Translational Modifications within Long Polypeptides

Unidirectional Single-File Transport of Full-Length Proteins through a Nanopore

Translocation of Linearized Full-Length Proteins through an Engineered Nanopore under Opposing Electrophoretic Force

Interpreting and Modeling Nanopore Ionic Current Signals During Unfoldase-Mediated Translocation of Single Protein Molecules

Multi-Pass, Single-Molecule Nanopore Reading of Long Protein Strands with Single-Amino Acid Sensitivity

Stanford Researchers Use Text and Images from Pathologists’ Twitter Accounts to Train New Pathology AI Model

Researchers intend their new AI image retrieval tool to help pathologists locate similar case images to reference for diagnostics, research, and education

Researchers at Stanford University turned to an unusual source—the X social media platform (formerly known as Twitter)—to train an artificial intelligence (AI) system that can look at clinical laboratory pathology images and then retrieve similar images from a database. This is an indication that pathologists are increasingly collecting and storing images of representative cases in their social media accounts. They then consult those libraries when working on new cases that have unusual or unfamiliar features.

The Stanford Medicine scientists trained their AI system—known as Pathology Language and Image Pretraining (PLIP)—on the OpenPath pathology dataset, which contains more than 200,000 images paired with natural language descriptions. The researchers collected most of the data by retrieving tweets in which pathologists posted images accompanied by comments.

“It might be surprising to some folks that there is actually a lot of high-quality medical knowledge that is shared on Twitter,” said researcher James Zou, PhD, Assistant Professor of Biomedical Data Science and senior author of the study, in a Stanford Medicine SCOPE blog post, which added that “the social media platform has become a popular forum for pathologists to share interesting images—so much so that the community has widely adopted a set of 32 hashtags to identify subspecialties.”

“It’s a very active community, which is why we were able to curate hundreds of thousands of these high-quality pathology discussions from Twitter,” Zou said.

The Stanford researchers published their findings in the journal Nature Medicine titled, “A Visual-Language Foundation Model for Pathology Image Analysis Using Medical Twitter.”

James Zou, PhD

“The main application is to help human pathologists look for similar cases to reference,” James Zou, PhD (above), Assistant Professor of Biomedical Data Science, senior author of the study, and his colleagues wrote in Nature Medicine. “Our approach demonstrates that publicly shared medical information is a tremendous resource that can be harnessed to develop medical artificial intelligence for enhancing diagnosis, knowledge sharing, and education.” Leveraging pathologists’ use of social media to store case images for future reference has worked out well for the Stanford Medicine study. (Photo copyright: Stanford University.)

Retrieving Pathology Images from Tweets

“The lack of annotated publicly-available medical images is a major barrier for innovations,” the researchers wrote in Nature Medicine. “At the same time, many de-identified images and much knowledge are shared by clinicians on public forums such as medical Twitter.”

In this case, the goal “is to train a model that can understand both the visual image and the text description,” Zou said in the SCOPE blog post.

Because X is popular among pathologists, the United States and Canadian Academy of Pathology (USCAP), and Pathology Hashtag Ontology project, have recommended a standard series of hashtags, including 32 hashtags for subspecialties, the study authors noted.

Examples include:

“Pathology is perhaps even more suited to Twitter than many other medical fields because for most pathologists, the bulk of our daily work revolves around the interpretation of images for the diagnosis of human disease,” wrote Jerad M. Gardner, MD, a dermatopathologist and section head of bone/soft tissue pathology at Geisinger Medical Center in Danville, Pa., in a blog post about the Pathology Hashtag Ontology project. “Twitter allows us to easily share images of amazing cases with one another, and we can also discuss new controversies, share links to the most cutting edge literature, and interact with and promote the cause of our pathology professional organizations.”

The researchers used the 32 subspecialty hashtags to retrieve English-language tweets posted from 2006 to 2022. Images in the tweets were “typically high-resolution views of cells or tissues stained with dye,” according to the SCOPE blog post.

The researchers collected a total of 232,067 tweets and 243,375 image-text pairs across the 32 subspecialties, they reported. They augmented this with 88,250 replies that received the highest number of likes and had at least one keyword from the ICD-11 codebook. The SCOPE blog post noted that the rankings by “likes” enabled the researchers to screen for high-quality replies.

They then refined the dataset by removing duplicates, retweets, non-pathology images, and tweets marked by Twitter as being “sensitive.” They also removed tweets containing question marks, as this was an indicator that the practitioner was asking a question about an image rather than providing a description, the researchers wrote in Nature Medicine.

They cleaned the text by removing hashtags, Twitter handles, HTML tags, emojis, and links to websites, the researchers noted.

The final OpenPath dataset included:

  • 116,504 image-text pairs from Twitter posts,
  • 59,869 from replies, and
  • 32,041 image-text pairs scraped from the internet or obtained from the LAION dataset.

The latter is an open-source database from Germany that can be used to train text-to-image AI software such as Stable Diffusion.

Training the PLIP AI Platform

Once they had the dataset, the next step was to train the PLIP AI model. This required a technique known as contrastive learning, the researchers wrote, in which the AI learns to associate features from the images with portions of the text.

As explained in Baeldung, an online technology publication, contrastive learning is based on the idea that “it is easier for someone with no prior knowledge, like a kid, to learn new things by contrasting between similar and dissimilar things instead of learning to recognize them one by one.”

“The power of such a model is that we don’t tell it specifically what features to look for. It’s learning the relevant features by itself,” Zou said in the SCOPE blog post.

The resulting AI PLIP tool will enable “a clinician to input a new image or text description to search for similar annotated images in the database—a sort of Google Image search customized for pathologists,” SCOPE explained.

“Maybe a pathologist is looking at something that’s a bit unusual or ambiguous,” Zou told SCOPE. “They could use PLIP to retrieve similar images, then reference those cases to help them make their diagnoses.”

The Stanford University researchers continue to collect pathology images from X. “The more data you have, the more it will improve,” Zou said.

Pathologists will want to keep an eye on the Stanford Medicine research team’s progress. The PLIP AI tool may be a boon to diagnostics and improve patient outcomes and care.

—Stephen Beale

Related Information:

New AI Tool for Pathologists Trained by Twitter (Now Known as X)

A Visual-Language Foundation Model for Pathology Image Analysis Using Medical Twitter

AI + Twitter = Foundation Visual-Language AI for Pathology

Pathology Foundation Model Leverages Medical Twitter Images, Comments

A Visual-Language Foundation Model for Pathology Image Analysis Using Medical Twitter (Preprint)

Pathology Language and Image Pre-Training (PLIP)

Introducing the Pathology Hashtag Ontology

Separate Reports Shed Light on Why CDC SARS-CoV-2 Test Kits Failed During Start of COVID-19 Pandemic

HHS Office of Inspector General was the latest to examine the quality control problems that led to distribution of inaccurate test to clinical laboratories nationwide

Failure on the part of the Centers for Disease Control and Prevention (CDC) to produce accurate, dependable SARS-CoV-2 clinical laboratory test kits at the start of the COVID-19 pandemic continues to draw scrutiny and criticism of the actions taken by the federal agency.

In the early weeks of the COVID-19 pandemic, the CDC distributed faulty SARS-CoV-2 test kits to public health laboratories (PHLs), delaying the response to the outbreak at a critical juncture. That failure was widely publicized at the time. But within the past year, two reports have provided a more detailed look at the shortcomings that led to the snafu.

The most recent assessment came in an October 2023 report from the US Department of Health and Human Services Office of Inspector General (OIG), following an audit of the public health agency. The report was titled, “CDC’s Internal Control Weaknesses Led to Its Initial COVID-19 Test Kit Failure, but CDC Ultimately Created a Working Test Kit.”

“We identified weaknesses in CDC’s COVID-19 test kit development processes and the agencywide laboratory quality processes that may have contributed to the failure of the initial COVID-19 test kits,” the OIG stated in its report.

Prior to the outbreak, the agency had internal documents that were supposed to provide guidance for how to respond to public health emergencies. However, “these documents do not address the development of a test kit,” the OIG stated.

Jill Taylor, PhD

“If the CDC can’t change, [its] importance in health in the nation will decline,” said microbiologist Jill Taylor, PhD (above), Senior Adviser for the Association of Public Health Laboratories in Washington, DC. “The coordination of public health emergency responses in the nation will be worse off.” Clinical laboratories that were blocked from developing their own SARS-CoV-2 test during the pandemic would certainly agree. (Photo copyright: Columbia University.)

Problems at the CDC’s RVD Lab

Much of the OIG’s report focused on the CDC’s Respiratory Virus Diagnostic (RVD) lab which was part of the CDC’s National Center for Immunization and Respiratory Diseases (NCIRD). The RVD lab had primary responsibility for developing, producing, and distributing the test kits. Because it was focused on research, it “was not set up to develop and manufacture test kits and therefore had no policies and procedures for developing and manufacturing test kits,” the report stated.

The RVD lab also lacked the staff and funding to handle test kit development in a public health emergency, the report stated. As a result, “the lead scientist not only managed but also participated in all test kit development processes,” the report stated. “In addition, when the initial test kit failed at some PHLs, the lead scientist was also responsible for troubleshooting and correcting the problem.”

To verify the test kit, the RVD lab needed samples of viral material from the agency’s Biotechnology Core Facility Branch (BCFB) CORE Lab, which also manufactured reagents for the kit.

“RVD Lab, which was under pressure to quickly create a test kit for the emerging health threat, insisted that CORE Lab deviate from its usual practices of segregating these two activities and fulfill orders for both reagents and viral material,” the report stated.

This increased the risk of contamination, the report said. An analysis by CDC scientists “did not determine whether a process error or contamination was at fault for the test kit failure; however, based on our interviews with CDC personnel, contamination could not be ruled out,” the report stated.

The report also cited the CDC’s lack of standardized systems for quality control and management of laboratory documents. Labs involved in test kit development used two different incompatible systems for tracking and managing documents, “resulting in staff being unable to distinguish between draft, obsolete, and current versions of laboratory procedures and forms.”

Outside Experts Weigh In

The OIG report followed an earlier review by the CDC’s Laboratory Workgroup (LW), which consists of 12 outside experts, including academics, clinical laboratory directors, state public health laboratory directors, and a science advisor from the Association of Public Health Laboratories. Members were appointed by the CDC Advisory Committee to the Director.

This group cited four major issues:

  • Lack of adequate planning: For the “rapid development, validation, manufacture, and distribution of a test for a novel pathogen.”
  • Ineffective governance: Three labs—the RVD Lab, CORE Lab, and Reagent and Diagnostic Services Branch—were involved in test kit development and manufacturing. “At no point, however, were these three laboratories brought together under unified leadership to develop the SARS-CoV-2 test,” the report stated.
  • Poor quality control and oversight: “Essentially, at the start of the pandemic, infectious disease clinical laboratories at CDC were not held to the same quality and regulatory standards that equivalent high-complexity public health, clinical and commercial reference laboratories in the United States are held,” the report stated.
  • Poor test design processes: The report noted that the test kit had three probes designed to bind to different parts of the SARS-CoV-2 nucleocapsid gene. The first two—N1 (topology) and N2 (intracellular localization)—were designed to match SARS-CoV-2 specifically, whereas the third—N3 (functions of the protein)—was designed to match all Sarbecoviruses, the family that includes SARS-CoV-2 as well as the coronavirus responsible for the 2002-2004 SARS outbreak.

The N1 probe was found to be contaminated, the group’s report stated, while the N3 probe was poorly designed. The report questioned the decision to include the N3 probe, which was not included in European tests.

Also lacking were “clearly defined pass/fail threshold criteria for test validation,” the report stated.

Advice to the CDC

Both reports made recommendations for changes at the CDC, but the LW’s were more far-reaching. For example, it advised the agency to establish a senior leader position “with major responsibility and authority for laboratories at the agency.” This individual would oversee a new Center that would “focus on clinical laboratory quality, laboratory safety, workforce training, readiness and response, and manufacturing.”

In addition, the CDC should consolidate its clinical diagnostic laboratories, the report advised, and “laboratories that follow a clinical quality management system should have separate technical staff and space from those that do not follow such a system, such as certain research laboratories.”

The report also called for collaboration with “high functioning public health laboratories, hospital and academic laboratories, and commercial reference laboratories.” For example, collaborating on test design and development “should eliminate the risk of a single point of failure for test design and validation,” the LW suggested.

CBS News reported in August that the CDC had already begun implementing some of the group’s suggestions, including agencywide quality standards and better coordination with state labs.

However, “recommendations for the agency to physically separate its clinical laboratories from its research laboratories, or to train researchers to uphold new quality standards, will be heavy lifts because they require continuous funding,” CBS News reported, citing an interview with Jim Pirkle, MD, PhD, Director, Division of Laboratory Sciences, National Center for Environmental Health, at the CDC.

—Stephen Beale

Related Information:

CDC’s Internal Control Weaknesses Led to Its Initial COVID-19 Test Kit Failure, but CDC Ultimately Created a Working Test Kit  

Review of the Shortcomings of CDC’s First COVID-19 Test and Recommendations for the Policies, Practices, and Systems to Mitigate Future Issues      

Collaboration to Improve Emergency Laboratory Response: Open Letter from the Association of Pathology Chairs to the Centers for Disease Control and Prevention    

The CDC Works to Overhaul Lab Operations after COVID Test Flop

Scientists in Italy Develop Hierarchical Artificial Intelligence System to Analyze Bacterial Species in Culture Plates

New artificial intelligence model agrees with interpretations of human medical technologists and microbiologists with extraordinary accuracy

Microbiology laboratories will be interested in news from Brescia University in Italy, where researchers reportedly have developed a deep learning model that can visually identify and analyze bacterial species in culture plates with a high level of agreement with interpretations made by medical technologists.

They initially trained and tested the system to digitally identify pathogens associated with urinary tract infections (UTIs). UTIs are the source for a large volume of clinical laboratory microbiological testing.

The system, known as DeepColony, uses hierarchical artificial intelligence technology. The researchers say hierarchical AI is better suited to complex decision-making than other approaches, such as generative AI.

The researchers published their findings in the journal Nature titled, “Hierarchical AI Enables Global Interpretation of Culture Plates in the Era of Digital Microbiology.”

In their Nature paper, the researchers explained that microbiologists use conventional methods to visually examine culture plates that contain bacterial colonies. The scientists hypothesize which species of bacteria are present, after which they test their hypothesis “by regrowing samples from each colony separately and then employing mass spectroscopy techniques,” to confirm their hypotheses.

However, DeepColony—which was designed for use with clinical laboratory automation systems—looks at high-resolution digital scans of cultured plates and attempts to identify the bacterial strains and analyze them in much the same way a microbiologist would. For example, it can identify species based on their appearance and determine which colonies are suitable for analysis, the researchers explained.

“Working on a large stream of clinical data, and a complete set of 32 pathogens, the proposed system is capable of effectively assisting plate interpretation with a surprising degree of accuracy in the widespread and demanding framework of urinary tract infections,” the study authors wrote. “Moreover, thanks to the rich species-related generated information, DeepColony can be used for developing trustworthy clinical decision support services in laboratory automation ecosystems from local to global scale.”

Alberto Signoroni, PhD

“Compared to the most common solutions based on single convolutional neural networks (CNN), multi-network architectures are attractive in our case because of their ability to fit into contexts where decision-making processes are stratified into a complex structure,” wrote the study’s lead author Alberto Signoroni, PhD (above), Associate Professor of Computer Science, University of Brescia, and his researcher team in their Nature paper. “The system must be designed to generate useful and easily interpretable information and to support expert decisions according to safety-by-design and human-in-the-loop policies, aiming at achieving cost-effectiveness and skill-empowerment respectively.” Microbiologists and clinical laboratory managers will want to follow the further development of this technology. (Photo copyright: University of Brescia.)

How Hierarchical AI Works

Writing in LinkedIn, patent attorney and self-described technology expert David Cain, JD, of Hauptman Ham, LLP, explained that hierarchical AI systems “are structured in layers, each with its own distinct role yet interconnected in a way that forms a cohesive whole. These systems are significant because they mirror the complexity of human decision-making processes, incorporating multiple levels of analysis and action. This multi-tiered approach allows for nuanced problem-solving and decision-making, akin to a seasoned explorer deftly navigating through a multifaceted terrain.”

DeepColony, the researchers wrote, consists of multiple convolutional neural networks (CNNs) that exchange information and cooperate with one another. The system is structured into five levels—labeled 0 through 4—each handling a different part of the analysis:

  • At level 0, the system determines the number of bacterial colonies and their locations on the plate.
  • At level 1, the system identifies “good colonies,” meaning those suitable for further identification and analysis.
  • At level 2, the system assigns each good colony to a bacterial species “based on visual appearance and growth characteristics,” the researchers wrote, referring to the determination as being “pathogen aware, similarity agnostic.”

The CNN used at this stage was trained by using images of 26,213 isolated colonies comprising 32 bacterial species, the researchers wrote in their paper. Most came from clinical laboratories, but some were obtained from the American Type Culture Collection (ATCC), a repository of biological materials and information resources available to researchers.

  • At level 3, the system attempts to improve accuracy by looking at the larger context of the plate. The goal here is to “determine if observed colonies are similar (pure culture) or different (mixed cultures),” the researchers wrote, describing this step as “similarity aware, pathogen agnostic.” This enables the system to recognize variants of the same strain, the researchers noted, and has the effect of reducing the number of strains identified by the system.

At this level, the system uses two “Siamese CNNs,” which were trained with a dataset of 200,000 image pairs.

Then, at level 4, the system “assesses the clinical significance of the entire plate,” the researchers added. Each plate is labeled as:

  • “Positive” (significant bacterial growth),
  • “No significant growth” (negative), or
  • “Contaminated,” meaning it has three or more “different colony morphologies without a particular pathogen that is prevalent over the others,” the researchers wrote.

If a plate is labeled as “positive,” it can be “further evaluated for possible downstream steps,” using MALDI-TOF mass spectrometry or tests to determine susceptibility to antimicrobial measures, the researchers stated.

“This decision-making process takes into account not only the identification results but also adheres to the specific laboratory guidelines to ensure a proper supportive interpretation in the context of use,” the researchers wrote.

Nearly 100% Agreement with Medical Technologists

To gauge DeepColony’s accuracy, the researchers tested it on a dataset of more than 5,000 urine cultures from a US laboratory. They then compared its analyses with those of human medical technologists who had analyzed the same samples.

Agreement was 99.2% for no-growth cultures, 95.6% for positive cultures, and 77.1% for contaminated or mixed growth cultures, the researchers wrote.

The lower agreement for contaminated cultures was due to “a deliberately precautionary behavior, which is related to ‘safety by design’ criteria,” the researchers noted.

Lead study author Alberto Signoroni, PhD, Associate Professor of Computer Science, University of Brescia, wrote in Nature that many of the plates identified by medical technologists as “contaminated” were labeled as “positive” by DeepColony. “We maximized true negatives while allowing for some false positives, so that DeepColony [can] focus on the most relevant or critical cases,” he said.

Will DeepColony replace medical technologists in clinical laboratories any time soon? Not likely. But the Brescia University study indicates the direction AI in healthcare is headed, with high accuracy and increasing speed. The day may not be far off when pathologists and microbiologists regularly employ AI algorithms to diagnose disease.

—Stephen Beale

Related Information:

Hierarchical AI Enables Global Interpretation of Culture Plates in the Era of Digital Microbiology

Hierarchical Deep Learning Neural Network (HiDeNN): An Artificial Intelligence (AI) Framework for Computational Science and Engineering

An AI System Helps Microbiologists Identify Bacteria

This AI Research Helps Microbiologists to Identify Bacteria

Deep Learning Meets Clinical Microbiology: Unveiling DeepColony for Automated Culture Plates Interpretation

Experimental Low-Cost Blood Test Can Detect Multiple Cancers, Researchers Say

Test uses a new ultrasensitive immunoassay to detect a known clinical laboratory diagnostic protein biomarker for many common cancers

Researchers from Mass General Brigham, the Dana-Farber Cancer Institute, Harvard University’s Wyss Institute and other institutions around the world have reportedly developed a simple clinical laboratory blood test that can detect a common protein biomarker associated with multiple types of cancer, including colorectal, gastroesophageal, and ovarian cancers.

Best of all, the researchers say the test could provide an inexpensive means of early diagnosis. This assay could also be used to monitor how well patients respond to cancer therapy, according to a news release.

The test, which is still in experimental stages, detects the presence of LINE-1 ORF1p, a protein expressed in many common cancers, as well as high-risk precursors, while having “negligible expression in normal tissues,” the researchers wrote in a paper they published in Cancer Discovery titled, “Ultrasensitive Detection of Circulating LINE-1 ORF1p as a Specific Multicancer Biomarker.”

The protein had previously been identified as a promising biomarker and is readily detectable in tumor tissue, they wrote. However, it is found in extremely low concentrations in blood plasma and is “well below detection limits of conventional clinical laboratory methods,” they noted.

To overcome that obstacle, they employed an ultra-sensitive immunoassay known as a Simoa (Single-Molecule Array), an immunoassay platform for measuring fluid biomarkers.

“We were shocked by how well this test worked in detecting the biomarker’s expression across cancer types,” said lead study author gastroenterologist Martin Taylor, MD, PhD, Instructor in Pathology, Massachusetts General Hospital and Harvard Medical School, in the press release. “It’s created more questions for us to explore and sparked interest among collaborators across many institutions.”

Kathleen Burns, MD, PhD

“We’ve known since the 1980s that transposable elements were active in some cancers, and nearly 10 years ago we reported that ORF1p was a pervasive cancer biomarker, but, until now, we haven’t had the ability to detect it in blood tests,” said pathologist and study co-author Kathleen Burns, MD, PhD (above), Chair of the Department of Pathology at Dana-Farber Cancer Institute and a Professor of Pathology at Harvard Medical School, in a press release. “Having a technology capable of detecting ORF1p in blood opens so many possibilities for clinical applications.” Clinical laboratories may soon have a new blood test to detect multiple types of cancer. (Photo copyright: Dana-Farber Cancer Institute.)

Simoa’s Advantages

In their press release, the researchers described ORF1p as “a hallmark of many cancers, particularly p53-deficient epithelial cancers,” a category that includes lung, breast, prostate, uterine, pancreatic, and head and neck cancers in addition to the cancers noted above.

“Pervasive expression of ORF1p in carcinomas, and the lack of expression in normal tissues, makes ORF1p unlike other protein biomarkers which have normal expression levels,” Taylor said in the press release. “This unique biology makes it highly specific.”

Simoa was developed at the laboratory of study co-author David R. Walt, PhD, the Hansjörg Wyss Professor of Bioinspired Engineering at Harvard Medical School, and Professor of Pathology at Harvard Medical School and Brigham and Women’s Hospital.

The Simoa technology “enables 100- to 1,000-fold improvements in sensitivity over conventional enzyme-linked immunosorbent assay (ELISA) techniques, thus opening the window to measuring proteins at concentrations that have never been detected before in various biological fluids such as plasma or saliva,” according to the Walt Lab website.

Simoa assays take less than two hours to run and require less than $3 in consumables. They are “simple to perform, scalable, and have clinical-grade coefficients of variation,” the researchers wrote.

Study Results

Using the first generation of the ORF1p Simoa assay, the researchers tested blood samples of patients with a variety of cancers along with 406 individuals, regarded as healthy, who served as controls. The test proved to be most effective among patients with colorectal and ovarian cancer, finding detectable levels of ORF1p in 58% of former and 71% of the latter. Detectable levels were found in patients with advanced-stage as well as early-stage disease, the researchers wrote in Cancer Discovery.

Among the 406 healthy controls, the test found detectable levels of ORF1p in only five. However, the control with the highest detectable levels, regarded as healthy when donating blood, “was six months later found to have prostate cancer and 19 months later found to have lymphoma,” the researchers wrote.

They later reengineered the Simoa assay to increase its sensitivity, resulting in improved detection of the protein in blood samples from patients with colorectal, gastroesophageal, ovarian, uterine, and breast cancers.

The researchers also employed the test on samples from 19 patients with gastroesophageal cancer to gauge its utility for monitoring therapeutic response. Although this was a small sample, they found that among 13 patients who had responded to therapy, “circulating ORF1p dropped to undetectable levels at follow-up sampling.”

“More Work to Be Done”

The Simoa assay has limitations, the researchers acknowledged. It doesn’t identify the location of cancers, and it “isn’t successful in identifying all cancers and their subtypes,” the press release stated, adding that the test will likely be used in conjunction with other early-detection approaches. The researchers also said they want to gauge the test’s accuracy in larger cohorts.

“The test is very specific, but it doesn’t tell us enough information to be used in a vacuum,” Walt said in the news release. “It’s exciting to see the early success of this ultrasensitive assessment tool, but there is more work to be done.”

More studies will be needed to valid these findings. That this promising new multi-cancer immunoassay is based on a clinical laboratory blood sample means its less invasive and less painful for patients. It’s a good example of an assay that takes a proteomic approach looking for protein cancer biomarkers rather than the genetic approach looking for molecular DNA/RNA biomarkers of cancer.

—Stephen Beale

Related Information:

Ultrasensitive Blood Test Detects ‘Pan-Cancer’ Biomarker

New Blood Test Could Offer Earlier Detection of Common Deadly Cancers

Ultrasensitive Detection of Circulating LINE-1 ORF1p as a Specific Multicancer Biomarker

Noninvasive and Multicancer Biomarkers: The Promise of LINE-1 Retrotransposons

LINE-1-ORF1p Is a Promising Biomarker for Early Cancer Detection, But More Research Is Needed

‘Pan-Cancer’ Found in Highly Sensitive Blood Test

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