This is another approach to the liquid biopsy that clinical laboratories and pathologists may use to detect cancer less invasively
Screening for cancer usually involves invasive, often painful, costly biopsies to provide samples for diagnostic clinical laboratory testing. But now, scientists at the University of Technology (UTS) in Sydney, Australia, have developed a novel approach to identifying tumorous cells in the bloodstream that uses imaging to cause cells with elevated lactase to fluoresce, according to a UTS news release.
The UTS researchers created a Static Droplet Microfluidic (SDM) device that detects circulating tumor cells (CTC) that have separated from the cancer source and entered the bloodstream. The isolation of CTCs is an intrinsic principle behind liquid biopsies, and microfluidic gadgets can improve the efficiency in which problematic cells are captured.
The University of Technology’s new SDM device could lead the way for very early detection of cancers and help medical professionals monitor and treat cancers.
“Managing cancer through the assessment of tumor cells in blood samples is far less invasive than taking tissue biopsies. It allows doctors to do repeat tests and monitor a patient’s response to treatment,” explained Majid E. Warkiani, PhD, Professor, School of Biomedical Engineering, UTS, and one of the authors of the study, in a news release. Clinical laboratories and pathologists may soon have a new liquid biopsy approach to detecting cancers. (Photo copyright: University of New South Wales.)
Precision Medicine a Goal of UTS Research
The University of Technology’s new SDM device differentiates tumor cells from normal cells using a unique metabolic signature of cancer that involves the waste product lactate.
“A single tumor cell can exist among billions of blood cells in just one milliliter of blood, making it very difficult to find,” explained Majid E. Warkiani, PhD, a professor in the School of Biomedical Engineering at UTS and one of the authors of the study, in the news release.
“The new [SDM] detection technology has 38,400 chambers capable of isolating and classifying the number of metabolically active tumor cells,” he added.
“In the 1920s, Otto Warburg discovered that cancer cells consume a lot of glucose and so produce more lactate. Our device monitors single cells for increased lactate using pH sensitive fluorescent dyes that detect acidification around cells,” Warkiani noted.
After the SDM device has detected the presence of questionable cells, those cells undergo further genetic testing and molecular analysis to determine the source of the cancer. Because circulating tumor cells are a precursor of metastasis, the device’s ability to identify CTCs in very small quantities can aid in the diagnosis and classification of the cancer and the establishment of personalized treatment plans, a key goal of precision medicine.
The new technology was also designed to be operated easily by medical personnel without the need for high-end equipment and tedious, lengthy training sessions. This feature should allow for easier integration into medical research, clinical laboratory diagnostics, and enable physicians to monitor cancer patients in a functional and inexpensive manner, according to the published study.
“Managing cancer through the assessment of tumor cells in blood samples is far less invasive than taking tissue biopsies. It allows doctors to do repeat tests and monitor a patient’s response to treatment,” stated Warkiani in the press release.
The team have filed for a provisional patent for the device and plan on releasing it commercially in the future.
Other Breakthroughs in MCED Testing
Scientists around the world have been working to develop a simple blood test for diagnosing cancer and creating optimal treatment protocols for a long time. There have been some notable breakthroughs in the advancement of multi-cancer early detection (MCED) tests, which Dark Daily has covered in prior ebriefings.
According to the Centers for Disease Control and Prevention (CDC), cancer ranks second in the leading causes of death in the US, just behind heart disease. There were 1,603,844 new cancer cases reported in 2020, and 602,347 people died of various cancers that year in the US.
According to the National Cancer Institute, the most common cancers diagnosed in the US annually include:
Cancer is a force in Australia as well. It’s estimated that 151,000 Australians were diagnosed with cancer in 2021, and that nearly one in two Australians will receive a diagnosis of the illness by the age of 85, according to Cancer Council South Australia.
The population of Australia in 2021 was 25.69 million, compared to the US in the same year at 331.9 million.
The development of the University of Technology’s static droplet microfluidic device is another approach in the use of liquid biopsies as a means to detect cancer less invasively.
More research and clinical studies are needed before the device can be ready for clinical use by anatomic pathology groups and medical laboratories, but its creation may lead to faster diagnosis of cancers, especially in the early stages, which could lead to improved patient outcomes.
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.
Research goal was to isolate circulating tumor cells in venipuncture samples with improved purity compared to standard spiral chips
Many research teams are pursuing the goal of creating assays that detect circulating tumor cells (CTCs) that would allow earlier and more accurate diagnosis of cancer. Now comes news of a unique technology developed at the University of Michigan (U-M) Ann Arbor that showed promised in an early study.
The method of using CTCs to diagnose cancer in patients, while further analyzing specific characteristics of a given cancer case, shows promise as an innovative tool for clinical laboratories and oncologists. However, current approaches face challenges when it comes to proving accuracy and establishing thresholds that might indicate the need for further action.
Researchers at U-M believe they may have solved that problem. They created “Labyrinth,” a “label-free microfluidic device” that condenses 637mm of channels—including 11 loops and 56 corners—onto a 500μm-wide chip that uses inertia and Dean flow to separate white blood cells and CTCs from venipuncture samples at rates as high as 2.5ml per minute. These results improve upon the traditional spiral chip design.
Publishing their findings in Cell Systems, first author of the study Eric Lin, PhD, noted, “With the recent advances in tools for genomic characterization, it is more compelling than ever to look at the tumor heterogeneity to understand tumor progression and resistance to therapies. The Labyrinth device enabled high yields of CTCs without the bias induced by antibody-based selection, allowing the identification of true biological tumor heterogeneity.”
The graphic above, taken from the University of Michigan study, demonstrates the “High-throughput and label-free Labyrinth device that enables single CTC isolation and gene expression characterization.” According to the researchers, “Labyrinth offers a cell-surface marker-independent single-cell isolation platform to study heterogeneous CTC subpopulations.” The U-M study shows promise in creating tools for oncologist and clinical laboratory cancer treatment. (Image copyright: University of Michigan/Cell Systems.)
Challenges in the Isolation of CTCs
The Labyrinth chip is not the first device to assist in isolating CTCs. The U-M study notes that while immune-affinity capture is a validated approach to prognosis, therapeutic monitoring and molecular diagnostics, it does not work with all cancer cases. The researchers also note the method creates challenges in single-cell analysis later.
Existing label-free methods of isolation, such as deterministic lateral displacement, microfluidic flow fractionation, and acoustic-based separation, avoid these concerns but face issues of their own. The researchers noted, “Issues encountered with these approaches include pore clogging, high-pressure drop, pre-fixation to prevent CTC loss, low throughput, and excessive non-specific cell retention.”
The researchers further clarified that a major factor separating the Labyrinth chip from other methods is the ability to identify CTC subpopulations without the need for manual selection based on positive or negative protein expression. Thus, improving the ability to conduct further single-cell analysis from the results. Testing of the Labyrinth chip involved a variety of cancer cell lines, including:
· Human breast (MCF-7);
· Pancreatic (PANC-1);
· Prostate (PC-3); and,
· Lung (H1650).
And while standard spiral chips are already a common method for conducting size-based sorting, the purity of results is less than ideal with thousands of other cells remaining in the sample.
The researchers reported that the Labyrinth chip recovered 91.5% (plus or minus 0.9%) of cancer cells and removed 91.4% (plus or minus 3.3%) of white blood cells in a spiked buffer test.
“Bigger cells, like most cancer cells, focus pretty fast due to the curvature. But the smaller the cell is, the longer it takes to get focused,” Sunitha Nagrath, PhD, Associate Professor of Chemical Engineering and a lead developer of the Labyrinth chip, stated in a U-M news release. “The corners produce a mixing action that makes the smaller white blood cells come close to the equilibrium position much faster.”
Labyrinth also supports a series configuration of multiple chips. While testing two chips in series, researchers noted “a two-log improvement in tumor cell enrichment over the single Labyrinth.” They claim this is a higher purity than other label-free methods they studied, while adding only five minutes to processing times.
Sunitha Nagrath, PhD (above), is an Associate Professor of Chemical Engineering at the University of Michigan, and one of the lead developers of the Labyrinth chip. “You cannot put a box around these cells,” she noted in the U-M news release. “The markers for them are so complex, there is no one marker we could target for all these stages.” (Photo copyright: University of Michigan.)
Current Testing Using the Labyrinth Chip
The chip is already in use in a clinical trial for an aggressive form of breast cancer by Max Wicha, MD, Madeline and Sidney Forbes Professor of Oncology, Founding Director Emeritus, University of Michigan Comprehensive Cancer Center, and co-author of the Cell Systems study, who lead the study along with Nagrath.
The trial involves the attempted activation of adult system cells by blocking the signaling molecule interleukin-6. Wicha suspects the molecule enables cancer stem cells as well. “We think that this may be a way to monitor patients in clinical trials,” he said in the U-M news release. “Rather than just counting the cells, by capturing them, we can perform molecular analysis [to] know what we can target with treatments.”
The news release further highlights how this chip is specifically suited to such a task. As cancer stem cells transition from stem-like cells to more ordinary cell types, their gene expression shifts as well. This creates an issue when using conventional cell targeting. Nagrath notes this concern, stating, “The markers for [cancer stem cells] are so complex, there is no one marker we could target for all these stages.”
The Labyrinth chip shows potential for overcoming one of the biggest hurdles to leveraging CTCs to diagnose cancers and develop personalized therapies. Currently, the chip can output to Fluidigm, DEPArray by Silicon Biosystems, and RainDance Technologies’ RainDrop Digital PCR System.
The U-M researchers hope that future research will yield additional applications and compatible systems to further improve the ability for medical laboratories to use CTCs in the early detection and monitoring of cancer cases.
The target for this new high-speed microscope are Circulating cancer tumor cells (CTC). CTCs are the precursors to metastasis and metastatic cancer accounts for about 90% of cancer mortalities. However, CTCs are difficult to find and identify. Among a billion healthy cells, only a minute number of CTCs exist. (more…)
Surgical pathologists could gain new tool to diagnose many types of cancers
It might soon be possible to determine the HER2 status of breast cancer patients from blood samples rather than tissue biopsies. If this new technology proves feasible, it would give surgical pathologists and medical laboratories a different, and possibly less complex, methodology to use when assessing a case of breast cancer.
In its report about the study, Medscape Medical News, wrote that “HER2 status derived from circulating tumor cells (CTCs) from breast cancer patients was generally concordant with that derived from tumor tissue” and that “CTCs could prove to be an alternative to biopsies for assessing tumor tissue for biomarker status.”
