Scientists from the National University of Singapore (NUS) have developed a new, low-cost blood test for detecting cancers. The method works by sequencing blood samples that have been heated to isolate cancer-specific signatures in an individual’s blood.
The liquid biopsy, which is a non-invasive alternative to traditional tissue biopsies, costs about S$50 (around Rs 3,100) from start to finish, compared to other sequencing methods that can cost up to S$1,000 (around Rs 62,000), the researchers said.
“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 Cheow Lih Feng, assistant professor at NUS, who led the team behind the development of the test, adding that this could make it a mainstay in cancer diagnosis.
The researchers said the test, called Heatrich-BS, improves upon current liquid biopsies as it does not require the entire genome to be sequenced to find the presence of cancer-specific biomarkers. This is a labour-intensive and expensive process.
Instead, the new method discards the non-informative sections of DNA and targets regions where cancer biomarkers are most concentrated. This is achieved by heating the DNA sample, which leaves regions known as CpG islands intact, while destroying the rest of the genetic material.
The remaining genetic material, comprising about 1% of the DNA, is then sequenced to see if it contains cancer biomarkers.
“We are getting a much more sensitive assay at almost the same costs as compared to simple protein biomarker tests,” said Cheow. “Our method really concentrates on sequencing these regions that matter the most.”
The technique can detect tumour load with a 20-fold reduction in the length of DNA that needs to be sequenced to identify cancer markers when compared to standard liquid biopsy techniques.
To validate this new method, the researchers conducted a pilot study with samples from 14 people with colorectal cancer. The samples were collected at different points of time for everyone, and results from the test were compared with conventional testing methods.
In the case of five individuals, the Heatrich assay was able to detect cancer biomarkers earlier than conventional tools. The researchers further said that the performance of the test was comparable to that of a CT scan, the gold standard for diagnosing several types of cancers.
Moreover, the new test reduces the time taken from sample collection to when results are obtained to just 48 hours. “This way, doctors can monitor patients for their response to treatment and tailor their therapy regimes,” Cheow added.
The researchers have filed a patent for the new tool and are exploring its commercial applications.
