Jun 27, 2018 | Digital Pathology, Instruments & Equipment, Laboratory Instruments & Laboratory Equipment, Laboratory Management and Operations, Laboratory News, Laboratory Operations, Laboratory Pathology, Laboratory Testing, Management & Operations
Using GPIIb/IIIa inhibition, and ion chelation, researchers have developed a “universal” method for preserving blood up to 72 hours while keeping it viable for advanced rare-cell applications
Through microfluidics and automation, clinical laboratories and anatomic pathologists have been able to detect ever-smaller quantities of biomarkers and other indicators of chronic disease.
However, preserving sample quality is an essential part of analytical accuracy. This is particularly true in precision oncology and other specialties where isolating rare cells (aka, low abundance cells), such as circulating tumor cells (CTCs), is a key component to obtaining information and running diagnostics.
Publishing their finding in Nature, researchers at Massachusetts General Hospital Center for Engineering in Medicine (MGH-CEM) have developed a whole blood stabilization method that is ideal for rare-cell applications, and which preserves sample integrity for up to 72 hours.
Should further testing validate their findings and methodology, this change could allow greater use of central laboratories and other remote testing facilities that previously would not be available due to distance and sample travel time.
Keeping Blood Alive Is Not Easy
“At Mass. General, we have the luxury of being so integrated with the clinical team that we can process blood specimens in the lab typically within an hour or two after they are drawn,” stated lead author Keith Wong, PhD, former Research Fellow, MGH-CEM, and now Senior Scientist at Rubius Therapeutics, Boston, in a Mass General press release. “But to make these liquid biopsy technologies routine lab tests for the rest of the world, we need ways to keep blood alive for much longer than several hours, since these assays are best performed in central laboratories for reasons of cost-effectiveness and reproducibility.”
Study authors Wong and co-lead author Shannon Tessier, PhD, Investigator at MGH-CEM, noted that current FDA-approved blood stabilization methods for CTC assays use chemical fixation—a process that can result in degradation of sensitive biomolecules and kill the cells within the sample.
Without stabilization, however, breakdown of red cells, activation of leukocytes (white blood cells), and clot formation can render the results of analyzing a sample useless, or create issues with increasingly sensitive equipment used to run assays and diagnostics.
“We wanted to slow down the biological clock as much as possible by using hypothermia, but that is not as simple as it sounds,” says Tessier. “Low temperature is a powerful means to decrease metabolism, but a host of unwanted side effects occur at the same time.”
Researchers started by using hypothermic treatments to slow degradation and cell death. However, this created another obstacle—aggressive platelet coagulation. By introducing glycoprotein IIb/IIIa inhibitors, they found they could minimize this aggregation.
Keith Wong, PhD (left), a former Research Fellow, MGH-CEM, and now Senior Scientist at Rubius Therapeutics in Boston; and Shannon Tessier, PhD (right), Investigator at MGH-CEM, co-authored a study to develop a whole blood stabilization method that preserves sample integrity for up to 72 hours, making it possible to transport blood specimens further distances to central clinical laboratories for processing. (Photo copyrights: LinkedIn.)
Prior to microfluidic processing of their test samples, researchers applied a brief calcium chelation treatment. The result was efficient sorting of rare CTCs from blood drawn up to 72 hours prior, while keeping RNA intact and retaining cell viability.
“The critical achievement here,” says Tessier, “Is that the isolated tumor cells contain high-quality RNA that is suitable for demanding molecular assays, such as single-cell qPCR, droplet digital PCR, and RNA sequencing.”
Their testing involved 10 patients with metastatic prostate cancer. Sample integrity was verified by comparing CTC analysis results between fresh samples and preserved samples from the same patients using MGH-CEM’s own microfluidic CTC-iChip device.
Results showed a 92% agreement across 12 cancer-specific gene transcripts. For AR-V7, their preservation method achieved 100% agreement. “This is very exciting for clinicians,” declared David Miyamoto, MD, PhD, of Massachusetts General Hospital Cancer Center in the press release. “AR-V7 mRNA can only be detected using CTCs and not with circulating tumor DNA or other cell-free assays.”
Methodology Concerns and Future Confirmations
“Moving forward, an extremely exciting area in precision oncology is the establishment of patient-specific CTC cultures and xenograft models for drug susceptibility,” the study authors noted. “The lack of robust methods to preserve viable CTCs is a major roadblock towards this Holy Grail in liquid biopsy. In our preliminary experiments, we found that spiked tumor cells in blood remain highly viable (>80%) after 72 hours of hypothermic preservation.”
Despite this, they also acknowledge limitations on their current findings. The first is the need for larger-scale validation, as their testing involved a 10-patient sample group.
Second, they note that further studies will be needed to “more completely characterize whole-transcriptome alterations as a result of preservation, and to what extent they can be stabilized through other means, such as further cooling (e.g., non-freezing sub-zero temperatures) or metabolic depression.”
Researchers also note that their approach has multiple advantages for regulatory approval and further testing—GPIIb/IIIa inhibitors are both low-cost and already approved for clinical use, implementation requires no modification of existing isolation assays, and cold chain protocols are already in place allowing for easy adaptation to fit the needs of pathology groups, medical laboratories, and other diagnostics providers handling samples.
While still in its early stages, the methods introduced by the researchers at MGH-CEM show potential to allow both the facilities collecting samples and the clinical laboratories processing them greater flexibility and increased accuracy, as high-sensitivity assays and diagnostics continue to power the push toward personalized medicine and expand laboratory menus across the industry.
—Jon Stone
Related Information:
Whole Blood Stabilization for the Microfluidic Isolation and Molecular Characterization of Circulating Tumor Cells
Improved Blood Stabilization Should Expand Use of Circulating Tumor Cell Profiling
Genentech Scientists Zero In on “Liquid Biopsies” as a Way to Replace Tissue Biopsies in Breast Cancer
University of Michigan Researchers Use “Labyrinth” Chip Design in Clinical Trial to Capture Circulating Tumor Cells of Different Cancer Types
Super-Fast Microscope Captures Circulating Tumor Cells with High Sensitivity and Resolution in Real Time
Mar 2, 2018 | Instruments & Equipment, Laboratory Instruments & Laboratory Equipment, Laboratory Management and Operations, Laboratory News, Laboratory Operations, Laboratory Pathology, Laboratory Testing, Management & Operations
Liquid biopsy tests hold much promise. But inconsistencies in their findings provoke scrutiny and calls from researchers for further development before they can be considered reliable enough for diagnostic use
Many commercial developers of liquid biopsy tests tout the accuracy and benefits of their diagnostic technology. However, there are an equal number of medical laboratory experts who believe that this technology is not yet reliable enough for clinical use. Critics also point out that these tests are being offered as Laboratory Developed Tests (LDTs), which are internally developed and validated and have not undergone regulatory review.
Dark Daily has published several e-briefings on researchers who have sent the same patient samples to different genetic testing labs and received back materially different test results. Now, a new study by Johns Hopkins University concludes that liquid biopsy technology “must improve” before it should be relied upon for diagnostic and treatment decision making.
‘Certification for Medical Laboratories Must Improve’
Liquid Biopsy is the term for drawing whole blood and looking for cancer/tumor cells circulating in the blood stream. This is one factor in the imprecision of a liquid biopsy. Did the blood sample drawn actually have tumor cells? After all, only a limited number of tumor cells, if present, are in circulation.
Researchers at The James Buchanan Brady Urological Institute at Johns Hopkins School of Medicine know this and recently compared results of two liquid biopsy tests to determine which one would be more beneficial for patients. They published their findings in the December issue of JAMA Oncology.
Gonzalo Torga, MD (above left), and Kenneth J. Pienta, MD (above right), are the two Johns Hopkins Medicine doctors who conducted the recent study into the efficacy of liquid biopsy laboratory developed tests (LDTs) offered by different medical laboratory companies. They published their findings in JAMA Oncology. (Photos copyright: Johns Hopkins.)
To perform the study, researchers collected blood samples from 40 patients with metastatic prostate cancer and sent the same patient samples to two different Clinical Laboratory Improvement Amendments (CLIA) licensed College of American Pathologists (CAP) accredited laboratories. The labs then performed DNA next-generation sequencing on the samples following the directions of the two liquid biopsy manufacturers.
In reporting the DNA findings and results from the two medical laboratory companies, researchers discovered that the results completely matched in only three of the 40 patients! The Johns Hopkins researchers are concerned that patients could be prescribed certain cancer treatments based on which lab company’s liquid biopsy test their physician orders, instead of an accurate identification of the unique mutations in their tumors.
“Liquid biopsy is a promising technology, with an exceptional potential to impact our ability to treat patients, but it is a new technology that may need more time and experience to improve,” Gonzalo Torga, MD, Postdoctoral Fellow and Instructor at Johns Hopkins, and the lead author of the study, told Forbes. “We can’t tell from these studies which laboratory’s panel is better, but we can say that certification for these laboratories must improve.”
Unlocking New View of Tumors
Two commercial tests were used for the study:
Guardant360 from Guardant Health, Inc., uses digital sequencing to analyze genomic data points at the single molecular level. It examines 73 genes, including all National Comprehensive Cancer Network (NCCN) listed genes. The test searches for DNA fragments among billions of cells and digitally tags each fragment. This process unlocks a view of tumors that is not seen with tissue biopsies, which helps doctors prescribe the best treatment options for a particular patient.
“As a simple blood test, it provides physicians with a streamlined, cost-effective method to identify genomic alterations that can comprehensively influence a patient’s therapy response,” Helmy Eltoukhy, PhD, co-founder and Chief Executive Officer at Guardant Health, told MDBR.
“The only way of keeping ahead of those diseases and tracking those mutations has been through surgery, through doing a tissue biopsy and physically cutting a piece of the tumor out and sequencing it,” Eltoukhy noted in an interview with Xconomy. “What we’re able to do is essentially get the same, or sometimes better performance to tissue biopsy, but through two teaspoons of blood.”
According to the Guardant Health website, it takes just 14 days for a full report from Guardant360 to reach the ordering physician. In addition, the blood test provides samples with an adequate level of cell-free DNA to test 99.8% of the time and reduces errors and false positives found in standard sequencing methods by 1,000 times. It is common for samples used for tissue sequencing to have insufficient DNA for testing 20% to 40% of the time.
“We believe that conquering cancer is at its core a big data problem, and researchers have been data-starved,” explained Eltoukhy in VentureBeat. “Our launch of the world’s first commercial comprehensive liquid biopsy sparked a boom in cancer data acquisition. Every physician who orders one of our tests, and every patient whose tumor DNA we sequence, adds to this larger mission by improving our understanding of this complex disease.”
PlasmaSELECT-R64, manufactured by Personal Genome Diagnostics (PGDx), evaluates a targeted panel of 64 genes that have biological and functional relevance in making treatment decisions. PGDx announced the expanded version of its PlasmaSELECT assay in March of 2017.
“We are proud to launch the revolutionary PlasmaSELECT 64 expanded assay just six months after we introduced the most accurate, clinically actionable liquid biopsy tumor profiling assay to the market,” said Doug Ward, Chief Executive Officer at PGDx, in a press release. “This update is the first liquid biopsy assay that includes MSI (microsatellite instability) testing as a biomarker for high tumor mutational load, thereby providing cancer patients and their oncologists with information on whether they might be candidates for immuno-oncology therapies. The ability to generate DNA tumor profiling non-invasively using blood or plasma offers many advantages and makes genomic testing more accessible and usable.”
Regulations of LDTs Could be Needed to Improve Liquid Biopsy Tests
There are pathologists and clinical laboratory professionals who believe the technology behind liquid biopsies is not yet reliable enough for clinical use. The tests are being offered as LDTs, which are internally developed and validated, and the Food and Drug Administration (FDA) allows LDTs to be sold without regulatory reviews at this time. However, there are discussions regarding if and how to regulate LDTs, the outcome of which could impact how clinical laboratories are allowed to market the LDTs they develop.
Clearly, liquid biopsies are still in their relatively early stages of development. More testing and evaluation is needed to determine their efficacy. However, their potential to revolutionize cancer detection and care is obvious and a strong motivator for LTD developers, which means there will be future developments worth noting.
—JP Schlingman
Related Information:
Oncologists, Beware: Expensive Liquid Biopsy Tests Produce Conflicting Results
One Patient, Two Cancer DNA Tests, Two Different Results
Liquid Biopsy Results Differed Substantially Between Two Providers
Cancer Screening Firm Guardant Health Raises $360 Million to Sequence Tumor DNA of 1 Million Patients
Guardant Health Launches Guardant360 Blood Test in US
With $100M, Guardant Health to Expand Reach of Blood Test for Cancer
Personal Genome Diagnostics’ Expanded PlasmaSELECT 64 Is First Liquid Biopsy Pan-Cancer Profiling Panel to Include MSI Analyses for Immuno-Oncology
‘Liquid Biopsy’ Picks up Cancer Biomarkers in Blood, Study Finds
FDA Reveals New Approach to Laboratory Developed Tests
Using Extracellular Vesicles, Researchers Highlight Viability of Liquid Biopsies for Cancer Biomarker Detection in Clinical Laboratories
Mar 4, 2016 | Digital Pathology, Laboratory Hiring & Human Resources, Laboratory Instruments & Laboratory Equipment, Laboratory Management and Operations, Laboratory News, Laboratory Pathology, Laboratory Testing
Of the five trends described in a report published by Kalorama, only two made the list for both years: Consolidation within the IVD industry and growth in molecular point of care
What a difference one year can make in the most significant trends influencing the in vitro diagnostics (IVD) industry, which also influences clinical laboratories, the largest customers of IVD manufacturers. These insights come from comparing the top five IVD trends for 2016 as identified by Kalorama Information from its top five IVD trends that it says dominated during 2015.
Kalorama is a division of MarketResearch.com, a company that publishes market research in the life sciences. In a report titled, “Five IVD Market Trends to Watch for in 2016,” it published its picks for the top five trends in IVD testing for 2016. The five most prominent trends recognized by the healthcare research marketer are as follows: (more…)
Jan 8, 2016 | Digital Pathology, Instruments & Equipment, Laboratory News, Laboratory Operations, Laboratory Pathology, Management & Operations
Pathologists will be interested to learn that this latest version of the acoustic tweezer device requires about five hours to identify the CTCs in a sample of blood
Medical laboratory leaders and pathologists are well aware that circulating tumor cells (CTCs) released by primary tumors into the bloodstream are fragile and easily damaged. Many studies have sought to find ways to separate CTCs from surrounding cells. Such a process could then be used as an early-detection biomarker to detect cancer from a sample of blood.
One team of researchers believe it has a way to accomplish this. These researchers are using sound waves to gently detect and isolate CTCs in blood samples. In turn, this could make it possible to diagnose cancer using “liquid biopsies” as opposed to invasive conventional biopsies.
Researchers from Carnegie Mellon University (CMU) in collaboration with researchers from the Massachusetts Institute of Technology (MIT) and Pennsylvania State University (Penn State) have developed a method for using acoustic tweezers and sound waves to separate blood-borne cancer cells from white blood cells. The research team believes this new device could one day replace invasive biopsies, according to a CMU article. (more…)
