Novel Low-Cost Cancer Testing Method Developed

Original from:Genomeweb

Scientists from the National University of Singapore (NUS) have discovered a novel low-cost method of testing for cancers. Called the Heatrich-BS assay, this new test sequences clinical samples that have been heated in order 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, compared to other sequencing methods that can cost 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, pointing to the potential for their assay to be used in regular cancer monitoring.

Liquid biopsies for cancer

Current methods of testing for cancers can suffer from a lack of sensitivity or from being too expensive to be used for regular screening. The DNA in our blood, the genetic information that tells our cells how to synthesize proteins and other important biological building blocks, is produced by different organs in our body. Cancer cells also release DNA into the bloodstream that can be detected by analyzing blood samples, known as liquid biopsies. However, sifting through all the genetic material in a sample – a method called whole-genome sequencing – 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 of people instead of inspecting every single 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

Asst Prof Cheow’s team has discovered a way to discard the non-informative sections in a patient’s DNA to target where most cancer-specific biomarkers are concentrated.

Our DNA is made up of molecules known as nucleotides: adenine (A), thymine (T), guanine (G) and cytosine (C). Cancer-specific signatures tend to be concentrated in areas of the genome that have high repetitions of C and G nucleotides, known as CpG islands, that make up only around 1 per cent of our genome.

“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 heat 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 really concentrates on sequencing these regions that matter the most.”

Benefitting patients, doctors and scientists