Japanese Researchers Create Inexpensive Palm-Size Microfilter That Captures Circulating Tumor Cells from Minute Amounts of Blood
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.
The KU scientists published their findings in Talanta, the international journal of pure and applied analytical chemistry, titled, “Detection of Cancer Cells in Whole Blood Using a Dynamic Deformable Microfilter and a Nucleic Acid Aptamer.”
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:
- The microfilter was made with photolithography, electroforming, and three-dimensional (3D) printing.
- 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:
- ARUP Laboratories
- Carolina BioOncology Institute
- London Health Sciences Centre
- MLabs, University of Michigan Pathology
- iCura Diagnostics
- Onco Decision Dx
CTC Tests Progress, But More to Do
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.
However, a separate CTC study published in Oncology Letters, titled, “Detection of Circulating Tumor Cells: Advances and Critical Concerns,” suggested that CellSearch and another CTC assay, Gilupi CellCollector, are “limited in their clinical application, largely due to their low sensitivity.”
“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.
—Donna Marie Pocius