Decision is part of UK effort to diagnose 75% of all cancers at stage I or stage II by 2028 and demonstrates to pathologists that the technology used in liquid biopsy tests is improving at a fast pace
Pathologists and medical laboratory scientists know that when it comes to liquid biopsy tests to detect cancer, there is plenty of both hope and hype. Nevertheless, following a successful pilot study at the Christie NHS Foundation Trust in Manchester, England, which ran from 2015-2021, the UK’s National Health Service (NHS) is pushing forward with the use of liquid biopsy tests for certain cancer patients, The Guardian reported.
NHS’ decision to roll out the widespread use of liquid biopsies—a screening tool used to search for cancer cells or pieces of DNA from tumor cells in a blood sample—across the UK is a hopeful sign that ongoing improvements in this diagnostic technology are reaching a point where it may be consistently reliable when used in clinical settings.
The national program provides personalized drug therapies based on the genetic markers found in the blood tests of cancer patients who have solid tumors and are otherwise out of treatment options. The liquid biopsy creates, in essence, a match-making service for patients and clinical trials.
Liquid Biopsy Genetic Testing for Cancer Patients
“The learnings from our original ‘Target’ study in Manchester were that genetic testing needs to be done on a large scale to identify rare genetic mutations and that broader access to medicines through clinical trials being undertaken across the country rather than just one site are required,” Matthew Krebs, PhD, Clinical Senior Lecturer in Experimental Cancer Medicine at the University of Manchester, told The Guardian.
Krebs, an honorary consultant in medical oncology at the Christie NHS Foundation Trust, led the Target National pilot study.
“This study will allow thousands of cancer patients in the UK to access genetic testing via a liquid biopsy. This will enable us to identify rare genetic mutations that in some patients could mean access to life-changing experimental medicines that can provide great treatment responses, where there are otherwise limited or no other treatment options available.”
Detecting cancers at earlier stages of disease—when treatment is more likely to result in improved survival—has become a strategic cancer planning priority in the UK, theBMJ noted.
“The NHS is committed to diagnosing 75% of all cancers at stage I or II by 2028, from around 50% currently,” the BMJ wrote. “Achieving such progress in less than a decade would be highly ambitious, even without disruption caused by the COVID-19 pandemic. In this context, considerable hope has been expressed that blood tests for circulating free DNA—sometimes known as liquid biopsy—could help achieve earlier detection of cancers.”
The Guardian noted that the UK’s initiative will use a liquid biopsy test made by Swiss-healthcare giant Roche.
“We can’t guarantee that we will find a fault in the genetic code of every cancer patient we recruit, or that if we do, there will be a suitable drug trial for them,” Matthew Krebs, PhD (above), lead scientist of the NHS’ Target National pilot study, told The Guardian. “However, as we learn more about the genetics of cancer in this study, it will help doctors and scientists develop new treatments to help people in the future. Ultimately, we hope liquid biopsy testing will be adopted into routine NHS care, but we need studies such as this to show the benefit of the test on a large scale and provide the evidence that patients can benefit from being matched to targeted medicines on the basis of the blood test.” (Photo copyright: Cancer Research UK Manchester Centre.)
In her article “The Promise of Liquid Biopsies for Cancer Diagnosis,” published in the American Journal of Managed Care (AJMC) Evidence-based Oncology, serial healthcare entrepreneur and faculty lecturer at Harvard Medical School Liz Kwo, MD, detailed the optimism surrounding the “revolutionary screening tool,” including its potential for:
identifying mechanisms of resistance to therapies,
measuring remaining disease after treatment,
assessing cancer relapse or resistance to treatment, and
eliminating risk surrounding traditional biopsies.
The AJMC article estimated the liquid biopsy market will be valued at $6 billion by 2030. However, Kwo also noted that clinical adoption of liquid biopsies in the US continues to face challenges.
Welch compared the investor hype surrounding liquid biopsies to that of the now-defunct blood testing company Theranos, which lured high-profile investors to pour millions into its unproven diagnostic technology.
“Effective cancer screening requires more than early detection. It also requires that starting therapy earlier helps people live to older ages than they would if they started treatment later,” he wrote. “If that doesn’t happen, liquid biopsies will only lead to people living longer with the knowledge they have a potentially incurable disease without extending their lives. These people would be subjected to cancer therapies and their toxicities earlier, but at a time when they would otherwise be experiencing no cancer-related signs or symptoms.”
And so, while there’s much excitement about the possibility of a minimally invasive way to detect cancer, anatomic pathology groups and clinical laboratories will have to wait and see if the hype and hope surrounding liquid biopsies is substantiated by further research.
Its low cost may advance liquid biopsy cancer testing used by anatomic pathologists and improve outcomes by speeding time to diagnosis and treatment
Researchers in Japan say they have created a circulating tumor cell (CTC) detection solution that is inexpensive and easy to run. Such a device would be of huge interest to investors and companies wishing to develop clinical laboratory tests that use circulating tumor cells in the blood to identify patients with cancer.
In a proof-of-concept study, researchers at Kumamoto University (KU) in Japan have developed and tested a microfilter device they claim can separate and capture CTCs in blood without large equipment, a KU news release reported.
According to Medgadget, the device is an “inexpensive, convenient, and highly sensitive filter that can successfully work in samples containing as few as five tumor cells in one milliliter of blood and does not require expensive equipment or reagents, unlike certain pre-existing cell capture technologies.”
This Technology Could Give Pathologists a Less-Invasive Cancer Test
As medical laboratory scientists and anatomic pathologists know, a CTC test is less invasive than tissue biopsy, which benefits patients. Furthermore, such a CTC test may enable earlier detection of cancer and start of treatment improving odds for success.
Still, there are many pitfalls to overcome when the challenge is to detect cancer cells in a milliliter (about .03 fluid ounce) of blood. As Medgadget put it, “A needle in a haystack doesn’t even come close.”
“Cancer cell count in the blood of cancer patients is extremely low. If these cells are easily detectable, cancer diagnosis may be possible by simply using a blood test, thus reducing patient burden,” the researchers wrote in their paper.
“This work demonstrates that our microfilter device can accurately detect trace amounts of cancer cells in blood,” said study leader Yuta Nakashima, PhD (above), Associate Professor, Department of Mechanical System Engineering at Kumamoto University, in the news release. “We expect it will be adopted for cancer diagnosis and treatment, including for early diagnosis of cancers that cannot be detected by imaging like CT and PET scans, post-operative follow-up, recurrence monitoring, and tailor-made treatments. In the future, we plan to use blood samples donated by cancer patients to verify the practical and clinical application of the method,” he added. Were it to become available, such a CTC test would be a boon for clinical laboratories and anatomic pathologists engaged in cancer diagnostics and treatment. (Photo copyright: Kumamoto University.)
How Does the CTC Filter Device Work?
The KU scientists created a palm-size “cancer detection device using a microfilter and nucleic acid aptamer,” the paper said, adding:
It includes slits to enable a deformation with force of blood pumping through the device.
As blood flows over the microfilter, cancer cells bind to the nucleic acid aptamer.
Force of blood flow opens microfilter slits, pushing away the healthy cells.
Cancer cells are left on the microfilter.
To test the microfilter the researchers used one milliliter of blood that was “spiked with cancer cells,” according to the paper. Findings include:
Detection of five CTCs in one milliliter of blood.
Blood cell removal rate of 98% suggested “no blood cells were absorbed by the microfilter,” the news release said.
The method “showed higher accuracy than the CellSearch System,” the Talanta paper noted.
The KU research team compared their microfluidic device to CellSearch, an FDA-cleared system for detecting CTCs from a blood sample.
CellSearch enables “identification, isolation, and enumeration of CTCs of epithelial origin,” according to Menarini Silicon Biosystems of Castel Maggiore, Italy. It works from a blood sample of 7.5 millimeters with “high level of sensitivity and specificity,” notes the company’s website.
According to Menarini, labs offering CellSearch CTC testing include:
The UK scientists admit that their research needs further study. Nakashima indicated he plans to test blood samples donated by cancer patients in subsequent device trials.
“Although great progress has been made, there is a long way to go before CTC-based liquid biopsy is widely used as a routine test in clinical application,” the authors of that study noted.
Nevertheless, even with more to do, liquid biopsy testing has come a long way, as multiple Dark Daily eBriefs reported over the years.
If the KU scientists succeed in bringing to market a microfilter that can reduce the cost of CTC detection by clinical laboratories while also improving cancer diagnostics, that will have a huge impact on cancer patients and is worthy of clinical laboratory leaders’ attention.
The discovery is yet another factor that must be considered when developing a liquid biopsy test clinical laboratories can use to detect cancer
How often do disruptive elements present in Liquid biopsies result in misdiagnoses and unhelpful drug therapies for cancer? Researchers at the University of Washington School of Medicine (UW Medicine) in Seattle wanted to know. And the results of their study provide another useful insight for pathologists about the elements that circulate in human blood which must be understood so that liquid biopsy tests can be developed that are not affected by that factor.
Based on their case series study of 69 men with advanced prostate cancer, the UW Medicine researchers determined that 10% of men have a clonal hematopoiesis of indeterminate potential (CHIP) that can “interfere” with liquid biopsies and cause incorrect reports and unneeded prostate cancer treatment, according to their paper published in the journal JAMA Oncology.
The UW Medicine researchers advised testing for “variants in the cell-free DNA (cfDNA)” shed in blood plasma to enable appropriate treatment for people with already diagnosed prostate cancer, noted to a UW Medicine news release.
According to pathologist Colin Pritchard, MD, PhD, Associate Professor of Laboratory Medicine and Pathology at the UW Medicine, who led the research team, “clonal hematopoiesis can interfere with liquid biopsies. For example, mutations in the genes BRCA1, BRCA2, and ATM have been closely linked to cancer development.
“The good news is that, by looking at the blood cellular compartment, you can tell with pretty good certainty whether something is cancer, or something is hematopoiesis,” he said in the news release.
What Does CHIP Interference Mean to a Clinical Laboratory Blood Test?
In their published study, the UW Medicine researchers stressed the “urgent need to understand cfDNA testing performance and sources of test interferences” in light of recent US Food and Drug Administration (FDA) clearance of two PARP inhibitors (PARPi) for prostate cancer:
“We found that a strikingly high proportion of DNA repair gene variants in the plasma of patients with advanced prostate cancer are attributable to CHIP,” the researchers wrote. “The CHIP variants were strongly correlated with increased age, and even higher than expected by age group.
“The high rate of CHIP may also be influenced by prior exposure to chemotherapy,” they added. “We are concerned that CHIP interference is causing false-positive cfDNA biomarker assessments that may result in patient harm from inappropriate treatment, and delays in delivering alternative effective treatment options.
“Without performing a whole-blood control, seven of 69 patients (10%) would have been misdiagnosed and incorrectly deemed eligible for PARP-inhibitor therapy based on CHIP interference in plasma. In fact, one patient in this series had a BRCA2 CHIP clone that had been previously reported by a commercial laboratory testing company with the recommendation to use a PARPi. To mitigate these risks, cfDNA results should be compared to results from whole-blood control or tumor tissue,” the researchers concluded.
To find the clinically relevant CHIP interference in prostate cancer cfDNA testing, researchers used the UW-OncoPlex assay (developed and clinically available at UW Medicine). The assay is a multiplexed next-generation sequencing panel aimed at detecting mutations in tumor tissues in more than 350 genes, according to the UW Medicine Laboratory and Pathology website.
“To improve cfDNA assay performance, we developed an approach that simultaneously analyzes plasma and paired whole-blood control samples. Using this paired testing approach, we sought to determine to what degree CHIP interferes with the results of prostate cancer cfDNA testing,” the researchers wrote in JAMA Oncology.
Men May Receive Unhelpful Prostate Cancer Drug Therapies
The research team studied test results from 69 men with advanced prostate cancer. They analyzed patients’ plasma cfDNA and whole-blood control samples.
Tumor sequencing enabled detection of germline (cells relating to preceding cells) variants from CHIP clones.
The UW Medicine study suggested CHIP variants “accounted for almost half of the somatic (non-germline) DNA repair mutations” detected by liquid biopsy, according to the news release.
> “About half the time when the plasma is thought to contain a mutation that would guide therapy with these drugs, it actually contains CHIP variants, not prostate cancer DNA variants. That means that in about half of those tested, a patient could be told that he should be administered a drug that is not indicated to treat to his cancer,” said Colin Pritchard, MD, PhD, pathologist and Associate Professor of Laboratory Medicine and Pathology at UW Medicine in the new release. (Photo copyright: University of Washington School of Medicine.)
Other detailed findings of the UW Medicine Study:
CHIP variants of 2% or more were detected in cfDNA from 13 of 69 men.
Seven men, or 10%, having advanced prostate cancer “had CHIP variants in DNA repair genes used to determine PARPi candidacy.
CHIP variants rose with age: 0% in those 40 to 50; 12.5% in men 51 to 60; 6.3% in those 61 to 70; 20.8% in men 71 to 80; and 71% in men 81 to 90.
Whole-blood control made it possible to distinguish prostate cancer variants from CHIP interference variants.
“Men with prostate cancer are at high risk of being misdiagnosed as being eligible for PARPi therapy using current cfDNA tests; assays should use a whole-blood control sample to distinguish CHIP variants from prostate cancer,” the researchers wrote in JAMA Oncology.
Liquid Biopsies Are ‘Here to Stay’
Surgical oncologist William Cance, MD, Chief Medical and Scientific Officer, American Cancer Society (ACS) in Atlanta, recognizes the challenge of tumor biology to liquid biopsies.
“Genetic abnormalities are only one piece of the puzzle. We need to look comprehensively at tumors for the best therapy, from their metabolic changes and protein signatures in the blood to the epigenetic modifications that may occur, as cancers take hold,” he told Oncology Times. “It’s not just shed DNA in the blood.”
The UW Medicine study demonstrates the importance of understanding how all elements in liquid biopsies interact to affect clinical laboratory test results.
“I think liquid biopsies are here to stay,” Cance told Oncology Times. “They’re all part of precision medicine, tailored to the individual.”
The new method employs a pH sensitive dye and AI algorithms to ‘distinguish between cells originating from normal and cancerous tissue, as well as among different types of cancer’ the researchers said
Might a pH-sensitive dye in tandem with an image analysis solution soon be used to identify cancerous cells within blood samples as well within tissue? Recent research indicates that could be a possibility. If further studies and clinical trials confirm this capability, then anatomic pathologists could gain another valuable tool to use in diagnosing cancers and other types of disease.
Currently, surgical pathologists use a variety of hematoxylin and eosin stains (H/E) to bring out useful features in cells and cell structures. So, staining tissue on glass slides is a common practice. Now, thanks to machine learning and artificial intelligence, anatomic pathologists may soon have a similar tool for spotting cancer cells within both tissue and blood samples.
Researchers at the National University of Singapore (NUS) have developed a method for identifying cancer that uses a pH sensitive dye called bromothymol blue. The dye reacts to various levels of acidity in cancer cells by turning colors. “The pH inside cancer cells tends to be higher than that of healthy cells. This phenomenon occurs at the very early phases of cancer development and becomes amplified as it progresses,” Labroots reported.
In “Machine Learning Based Approach to pH Imaging and Classification of Single Cancer Cells,” published in the journal APL Bioengineering, the NUS researchers wrote, “Here, we leverage a recently developed pH imaging modality and machine learning-based single-cell segmentation and classification to identify different cancer cell lines based on their characteristic intracellular pH. This simple method opens up the potential to perform rapid noninvasive identification of living cancer cells for early cancer diagnosis and further downstream analyses.”
According to an NUS news release, the bromothymol blue dye is “applied onto patients’ cells” being held ex vivo in cell culture dishes. The dye’s color changes depending on the acidity level of the cancer cells it encounters. Microscopic images of the now-visible cancers cells are taken, and a machine-learning algorithm analyzes the images before generating a report for the anatomic pathologist.
The NUS researchers claim the test can provide answers in about half an hour with 95% accuracy, Labroots reported.
“The ability to analyze single cells is one of the holy grails of health innovation for precision medicine or personalized therapy. Our proof-of-concept study demonstrates the potential of our technique to be used as a fast, inexpensive and accurate tool for cancer diagnosis,” said Lim Chwee Teck, PhD, NUS Society Professor and Director of NUS’ Institute for Health Innovation and Technology, in the NUS news release.
The novel technique for differentiating cancer cells from non-cancerous cells being developed at the National University of Singapore (NUS) could eventually become useful in detecting cancer cells in tissue samples, either obtained from tumor biopsies or blood samples. “As the number of cells in these samples can be in millions or even billions, the ability to detect the very few cancer cells among the others will be useful for clinicians,” NUS Society Professor and Director of NUS’ Institute for Health Innovation and Technology, Lim Chwee Teck, PhD (above) told The Straits Times. (Photo copyright: The Straits Times.)
AI Cell Analysis versus Laborious Medical Laboratory Steps
By developing an AI-driven method, Professor Lim and the NUS team sought to improve upon time-consuming techniques for identifying cells that traditionally involve using florescent probes, nanoparticles, and labeling steps, or for cells to be fixed or terminated.
“Unlike other cell analysis techniques, our approach uses simple, inexpensive equipment, and does not require lengthy preparation and sophisticated devices. Using AI, we are able to screen cells faster and accurately,” Professor Lim told Labroots. “Furthermore, we can monitor and analyze living cells without causing any toxicity to the cells or the need to kill them.”
The new technique may have implications for cancer detection in tumor tissue as well as in liquid biopsies.
“We are also exploring the possibility of performing the real-time analysis on circulating cancer cells suspended in blood,” Professor Lim said in the NUS news release. “One potential application for this would be in liquid biopsy where tumor cells that escaped from a primary tumor can be isolated in a minimally-invasive fashion from bodily fluids such as blood.”
Diagnosing Cancer in Real Time
The NUS’ method requires more research and clinical studies before it could become an actual tool for anatomic pathologists and other cancer diagnosticians. Additionally, the NUS researchers acknowledged that the focus on only four cell lines (normal cells, benign breast tumor cells, breast cancer cells, and pancreatic cancer cells) limited their study, as did lack of comparison with conventional florescent pH indicators.
Still, the NUS scientists are already planning more studies to advance their concept to different stages of cell malignancy. They envision a “real-time” version of the technique to enable recognition of cells and fast separation of those that need to be referred to clinical laboratories for molecular testing and/or genetic sequencing.
Medical laboratory leaders may want to follow the NUS study. An inexpensive AI-driven method that can accurately detect and classify cancer cells based on pH within the cells is provocative and may be eventually become integrated with other cancer diagnostics.
Breakthrough assay a ‘tenfold improvement over any prior assay for TERT mutations in the blood for brain tumors,’ MGH says in an affirmation of a diagnostic technology clinical labs might soon use
In recent years, investors have poured tens of millions of dollars into companies that promised to create non-invasive cancer tests which use liquid biopsy technology. Medical laboratory scientists even watched some of these companies hype their particular liquid biopsy tests before clinical studies generated data demonstrating that these tests produced accurate, reliable, and reproducible results.
For diagnosing cancer, a liquid biopsy test typically uses a blood sample with the goal of finding and identifying circulating tumor cells. Harvard Medical School researchers at Massachusetts General Hospital (MGH) believe they have developed just such a blood test. Their assay utilizes an enhanced form of liquid biopsy to detect and monitor one of the more prevalent types of brain tumor in adults—a glioma—and, according to a Harvard news release, can detect the presence of glioma at a significantly higher “overall sensitivity” than other similar liquid-biopsy tests.
Gliomas start in glia cells contained in the brain or spine. They account for about 30% of all brain and central nervous system tumors and 80% of all malignant brain tumors.
During their study, MGH researchers compared blood samples and tumor biopsy tissues from patients diagnosed with a glioma. They discovered that an assay they developed—a droplet digital polymerase chain reaction (ddPCR) blood test—could detect and monitor two types of telomerase reverse transcriptase (TERT) promoter gene mutations—C228T and C250T. These two gene mutations promote cancer growth and are present in more than 60% of all gliomas. The mutations are also present in 80% of all high-grade gliomas, which are the most aggressive and life-threatening types of the cancer.
In the press release, instructor in Neurosurgery at MGH and one of the study’s authors, Leonora Balaj, PhD, said, “By ‘supercharging’ our ddPCR assay with novel technical improvements, we showed for the first time that the most prevalent mutation in malignant gliomas can be detected in blood, opening a new landscape for detection and monitoring of the tumors.”
Bob Carter, MD, PhD (above), is neurosurgical oncologist and Chief of Neurosurgery at MGH, a Professor of Neurosurgery at Harvard Medical School, and one of the study’s authors. In the MGH press release he said, “We envision the future integration of tests like this one into the clinical care of our patients with brain tumors. For example, if a patient has a suspected mass on MRI scanning, we can take a blood sample before the surgery and assess the presence of the tumor signature in the blood and then use this signature as a baseline to monitor as the patient later receives treatment, both to gauge response to the treatment and gain early insight into any potential recurrence.” What Carter describes is precision medicine and could open new diagnostic opportunities for anatomic pathology groups and clinical laboratories. (Photo copyright: Massachusetts General Hospital.)
MGH’s Ten-Fold Improvement over Previous ddPCR Assays
A liquid biopsy is the sampling and analysis of non-solid tissue in the body—primarily blood. MGH’s liquid-biopsy method detects cancer by examining fragments of tumor DNA circulating in the bloodstream. Since the technique is mostly non-invasive, tests can be performed more frequently to track tumors and mutations and monitor treatment progression. Prior to this new method, brain tumors had been difficult to detect using liquid biopsies.
“Liquid biopsy is particularly challenging in brain tumors because mutant DNA is shed into the bloodstream at a much lower level than any other types of tumors,” Balaj said in the press release.
However, MGH’s new ddPCR assay has an overall sensitivity rate of 62.5% and a specificity of 90%, which represents a tenfold improvement over prior assays for TERT mutations in the blood.
And when testing the performance of the ddPCR assay in tumor tissue, the MGH researchers discovered their results were the same as results from a previous independently-performed clinical laboratory assessment of TERT mutations within collected tumor specimens. They also found that their assay could detect TERT mutations when looking at blood plasma samples collected at other facilities.
The researchers believe that their test could be performed in most clinical laboratories and can be utilized to follow the course of disease in cancer patients. The MGH researcher’s goal is to expand and adapt the blood test to diagnose, differentiate, and monitor other types of brain tumors in addition to gliomas.
Of course, more research will be needed before MGH’s new assay can become a vital tool in the fight against disease. However, this type of genetic analysis may soon provide pathologists with new techniques to more accurately diagnose and monitor cancers, and to provide healthcare providers with valuable data regarding which therapies would be the most beneficial for individual patients, a key element of precision medicine.
