Recognizing and treating brain tumors has been a challenge for researchers and clinicians in the past. However, new techniques such as liquid biopsy and advanced sequencing methods could make the detection of tumors in the brain much easier. Researchers at the Cancer Research UK (CRUK) Cambridge Institute have now made significant progress in developing fluid biopsies for brain tumors by detecting tumor DNA in the fluid around the brain and spine. Liquid biopsies are fluid samples from patients, such as blood or urine, that provide a less invasive way to monitor the disease than tumor biopsies. A less intrusive test could be very useful for brain tumors, where collecting samples for patients can be difficult and risky.
The results of the new study were published today in EMBO Molecular Medicine by an article entitled "Detecting cell-free DNA fragmentation and changes in copy number in cerebrospinal fluid of glioma patients".
"Liquid biopsies are promising for a range of cancers, but tests for brain tumors have lagged behind due to the low levels of tumor DNA found in body fluids, particularly in the blood," explains Florent Mouliere, co-lead investigator , PhD, who led the work as a scientist at the Cancer Research UK Cambridge Institute. "Our work shows that a cheap, readily available technique for analyzing tumor DNA in cerebrospinal fluid can be used. We anticipate that this technique could be used in the future to identify patients who might benefit from further testing that could help monitor their disease and provide tailor-made treatment approaches. "
In the current study, scientists from the Cambridge Institute of Cancer Research in the United Kingdom analyzed cerebrospinal fluid (CSF), in which the brain and spinal cord are bathed, in 13 patients with a brain tumor known as glioma. Surprisingly, they detected tumor DNA in five (39%) of the patients studied.
The researchers then used a cheap and widely used technique called sequencing the entire flat genome to detect brain tumor DNA. The CRUK team looked for major genetic changes, such as genes that were duplicated or lost. Researchers were able to identify tumor DNA in cerebrospinal fluid by examining the size of DNA fragments that are shorter than those of healthy cells. This provides another way to detect brain tumor DNA, possibly increasing the detection rate.
Interestingly, in one patient several tissue samples from her brain tumor were compared with her cerebrospinal fluid. The genetic changes were largely consistent, but the cerebrospinal fluid contained changes that were not present in some of the tissue samples, suggesting that cerebrospinal fluid samples may reflect the repertoire of genetic changes found in brain tumors.
Brain tumor survival is still low and there is an urgent need for research to find strategies to better manage these complex diseases. This study forms the important basis for the opportunity to bring fluid biopsies closer to this difficult-to-treat disease, "concludes Dr. Chares Swanton, chief clinician of Cancer Research UK. "Researchers now need to expand this work to a larger number of patients and find out if this approach could be used in the clinic, eg. For example, it indicates whether the treatment of a patient works. "