Researchers based in the U.K. are creating liquid biopsies for brain tumors by identifying tumor DNA in brain and spine fluid.
After analyzing cerebrospinal fluid (CSF), researchers from the Cancer Research UK Cambridge Institute, detected tumor DNA in 39 percent of 13 patients who had a type of brain tumor called a glioma.
Liquid biopsies are a less invasive way to monitor diseases, as opposed to tumor biopsies that are difficult and risky for patients. The team used a technique called shallow whole-genome sequencing to detect the brain tumor DNA and look for large genetic changes like genes being duplicated or lost.
“Liquid biopsies are showing great promise for a number of cancer types, but tests for brain tumours have lagged behind due to the low levels of tumour DNA found in body fluids, in particular the blood,” Florent Mouliere, PhD, co-first author, said in a statement.
“Our work shows that a cheap, easily available technique can be used to analyse tumour DNA in cerebrospinal fluid,” he added. “In the future, we envisage that this technique could be used to identify patients who may benefit from further tests that could help monitor their disease, opening up more tailored treatment approaches.”
The study represents the first time scientists were able to identify tumor DNA in CSF by looking at the size of the DNA fragments, which are generally shorter than those from healthy cells. This provides another method to detect brain tumor DNA and potentially increase the overall detection rate.
The researchers took multiple tissue samples from the brain tumor in one patient and compared it to that patient’s CSF. While the genetic changes matched, the CSF contained changes that were missed in some of the tissue samples, suggesting that CSF samples could reflect the repertoire of genetic alterations found in brain tumors.
According to the researchers, more than 11,400 people in the U.K. are diagnosed with brain tumors, with only 14 percent surviving the condition for more than 10 years.
“Survival for brain tumours remains low and there is an urgent need for research like this to identify strategies to better manage these complex diseases,” professor Charles Swanton, PhD, Cancer Research UK’s Chief Clinician, said in a statement. “This study lays important groundwork that brings the possibility of liquid biopsies for this hard to treat disease one step closer.
“The researchers will now need to expand this work into larger numbers of patients and find out whether this approach could have applications in the clinic, such as indicating whether a patient’s treatment is working,” he added.
The study was published in EMBO Molecular Medicine.