Breakthrough Liquid Biopsy Blood Test Method Enables Accurate, Rapid, Low-Cost Detection of Cancer

By LabMedica International staff writers
Posted on 24 Oct 2023

In the early stages of cancer, detecting circulating tumor DNA (ctDNA) in a blood sample is a challenging task. This is because ctDNA may only make up a minuscule 0.01% of the total DNA in the blood, which is otherwise 99.99% normal DNA. Furthermore, the genetic sequence of ctDNA is often identical to that of regular DNA. Existing methods for ctDNA detection require extracting and sequencing all circulating DNA and then using complex bioinformatics to differentiate between the cancerous and normal DNA. Now, an entirely new cancer detection method has been developed that avoids the normal cfDNA problem by physically isolating ctDNA fragments while completely removing background cfDNA fragments with the same sequence.

VolitionRx Limited (Austin, TX, USA) has developed a novel liquid biopsy technique that is the first to physically separate a specific class of tumor-derived ctDNA fragments from the blood. After the background normal DNA of the same sequence is removed, the remaining cancer-derived ctDNA fragments are detected using a simple, cost-effective PCR test. VolitionRx's method is built upon 13 years of research into the chemistry of circulating chromatin fragments. Their process employs Chromatin Immunoprecipitation (ChIP) to identify and physically separate tumor-derived chromatin fragments from normal DNA fragments. This is followed by quantitative real-time PCR (qPCR) testing to determine the presence of cancer. This new approach eliminates the need for expensive DNA sequencing and complex bioinformatics, paving the way for fast, cost-efficient cancer detection through routine blood tests.


Image: A new cancer detection method may pave the way for undiscovered biomarkers (Photo courtesy of VolitionRx)

In preliminary studies, Volition's method has shown promising results in isolating tumor-derived ctDNA fragments from plasma samples. Initial small-scale clinical tests were able to detect various types of cancers, even those at stage I. For instance, the method was able to identify 74% of leukemia cases with 96% specificity and 77% of colorectal cancers with 92% specificity, when utilizing 2-qPCR assays. This novel CTCF-ChIP/qPCR approach has immense potential for quick, accurate, and affordable cancer detection. It complements existing diagnostic methods and could be particularly effective for spotting early-stage diseases. The technique is also amenable to automation, making it practical for use in hospital labs.

"These early assays were developed using a leukemia model, but surprisingly also detected many other cancers including detecting colorectal cancer in a blood test with an accuracy approaching that of current Fecal Immunochemical Tests (FIT),” said Dr. Jake Micallef, Chief Scientific Officer at Volition. “The results to date are exciting and may pave the way for a whole new class of undiscovered biomarkers, with hundreds or thousands of possible targets. We are now developing a range of cancer-specific assays which we expect to be more accurate and look forward to sharing our progress beginning in Q1 2024."

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