Algorithm helps guide cancer treatment using circulating tumor DNA from blood samples microbiologystudy

A breakthrough by researchers at Peter Mac will allow scientists to detect, analyze and profile cancer tumors in patients via a simple blood test. The Dawson lab at Peter Mac has developed a method that can take circulating tumor DNA (ctDNA) from the patient’s blood and use an algorithm to identify cancer-related changes and patterns in their DNA.

Professor Sarah-Jane Dawson said the new method, called MisMatchFinder, looks for changes in DNA patterns caused by cancer’s impact on cells in the body. These changes are known as the mutational signature.

“Mutational signature information can often tell us more about the cancer including possible contributing causes as to why the cancer has developed and what type of therapy may be most effective,” Prof Dawson says.

“Currently, this information is obtained from conducting whole genome sequencing on a tissue biopsy sample from the cancer which is then compared to the person’s matched normal DNA sample that carries their original genetic code.

“This process is not only expensive and very time-consuming, but it can also be challenging to obtain tissue biopsy samples in some patients, so it is not a test that is conducted often.”

A standard biopsy requires a procedure to remove tissue or cells from the body, which can be difficult depending on the location of the tumor.

“Using the MisMatchFinder method, we can gather this information through a blood test, potentially making genome sequencing accessible to more patients and allowing us to personalize treatment to their specific cancer more quickly,” Prof Dawson says.

A paper titled “Unraveling mutational signatures with plasma circulating tumor DNA” and which describes the new method was published online in Nature Communications.

Co-author Dr. Dineika Chandrananda says the new method could change how cancer is monitored, as it could be used to keep track of a cancer’s changes over time without patients needing to undergo repeated biopsies.

“Excitingly, this new methodology will allow us to observe what is happening to the tumor over various timepoints,” says Dr. Chandrananda.

“MisMatchFinder brings considerable advances to the clinic and holds the potential to provide new insights into the use of mutational signatures. We believe that this knowledge will help guide and inform clinical decisions to optimize research-led cancer treatment strategies.”

This research is the first paper published by researchers at the new Collaborative Center for Genomic Cancer Medicine, a joint venture between Peter Mac and the University of Melbourne.