The novel technique offers tissue biopsies a promising non-invasive replacement.
Scientists from the National University of (NUS) have discovered a more cost-effective and efficient cancer diagnostic procedure. This novel low-cost method of testing for cancers is called the Heatrich-BS assay. This new test sequences clinical samples that have been heated to isolate cancer-specific signatures found in a patient’s blood.
The new method provides a promising non-invasive alternative to tissue biopsies. It costs around S$50 from start to finish. When compared to other sequencing methods costing up to S$1,000 to conduct.
Led by Assistant Professor Cheow Lih Feng, the team comprising researchers from the NUS Department of Biomedical Engineering under the College of Design and Engineering as well as the NUS Institute for Health Innovation & Technology is now exploring industry partnerships to bring their technology to market.
“When you have a S$50 test, it opens up a lot of avenues because it is affordable, so you can do the test quite regularly,” said Asst. Prof. Cheow points to the potential for their assay to be used in regular cancer monitoring.
Liquid biopsies for cancer
Current methods of testing for cancer can suffer from a lack of sensitivity or from being too expensive to be used for regular screening. The DNA in our blood is produced by different organs in our body.
Cancer cells also release DNA into the bloodstream, which can be detected by analyzing blood samples, known as liquid biopsies. However, sifting through all the genetic material in a sample can be expensive and labor intensive.
Some clinicians instead target cancer-specific signatures in cell-free DNA, almost like hunting for specific faces in a large crowd instead of inspecting every individual.
Yet, even such methods can be imperfect, Asst. Prof. Cheow explained. “Some patients may have cancer signatures that look slightly different and allow them to slip through the screening process,” he said.
A more sensitive test at a small fraction of the price
The team has figured out how to remove the useless DNA segments from a patient. They did this to focus on the regions where the majority of cancer-specific biomarkers are found.
The nucleotides that make up our DNA are adenine (A), thymine (T), guanine (G), and cytosine (C). Cancer-specific signals are frequently found in regions of the genome with high C and G nucleotide repetitions, or so-called CpG islands.
“We were performing some unrelated experiments, and one of our researchers heated a sample,” Asst. Prof. Cheow said, recounting the team’s accidental discovery that heats destroyed non-informative sections of the genome, but left CpG island largely intact. This allowed them to sequence the remaining genome and detect the presence of cancers for a minute fraction of the average market price. “We are getting a much more sensitive assay at almost the same costs as compared to simple protein biomarker tests,” he said, “Our method concentrates on sequencing these regions that matter the most.”
The NUS team published their findings in the scientific journal Science Advances.
Benefiting patients, doctors, and scientists
The National Cancer Center in Singapore has used the Heatrich-BS test for evaluating patients with colorectal cancer.
The scientists discovered a strong correlation between the amount of cancer-specific DNA found in a patient’s blood sample and the size of their tumours over time. It was done by comparing the outcomes of their blood analysis with CT scans that captured the size of patients’ tumours.
“This way, doctors can monitor patients for their response to treatment and tailor their therapy regimes,” Asst. Prof. Cheow said. He also pointed out that their method has the potential to work universally across all types of cancer since they all demonstrate the property of enriching CpG islands with cancer-specific biomarkers. “It’s a one-size-fits-all,” he added.
Future:
Asst. Prof. Cheow and his team are now exploring ways to commercialize their assay. They are partnering with pharmaceutical and biotechnology companies that can help bring the Heatrich-BS assay to market.
“We are excited about our results and licensing discussions are underway,” he said.
The assay may also help accelerate future academic research. This will help scientists study different subtypes of cancer for a low cost. It will therefore improve the development of future cancer diagnoses and therapies.
Parvathy Sukumaran 
