Researchers at Cambridge University have developed two tests that can detect a specific brain tumor via patient blood plasma or urine. Despite only a small number of patients being analyzed, the results were promising.
The tests work by finding mutated DNA, shed by tumor cells when they die, known as cell free DNA or cfDNA. Scientists have known that cfDNA with similar mutations to the original tumor, can be found in blood and urine in very low levels. However the challenge has been developing a test sensitive enough to detect these very specific mutations.
In more depth:
Two different tests were conducted by the researchers, both led by Dr Florent Mouliere who is based at the Rosenfeld Lab of the Cancer Research UK Cambridge Institute and at the Amsterdam UMC.
First they set their focus on patients who had previously had glioma removed and biopsied. The team then designed a tumor-guided sequencing test that was able to look for mutations in the tumor tissue within the cfDNA of the patients urine, CSF and blood plasma. The results were extremely encouraging, with the test detecting cfDNA in 7 out of 8 CSF samples, 10 out of 12 plasma blood samples and for the urine samples 10 out of 16.
For the second test, using ‘whole genome sequencing’, the researchers analyzed samples of giloma patients, those with non-malignant brain disorders and a group of healthy people. They looked for other patterns in the cfDNA that could also indicate the presence of a tumor.
Again their findings were promising. They found the fragments of cfDNA which came from the blood plasma and urine samples were different sizes in those with brain tumors to those with no tumors in CSF (Cerebrospinal fluid (CSF) is a clear fluid that surrounds the brain and spinal cord.) The data was then fed to a machine learning algorithm which successfully differentiated between the urine samples of people with and without glioma.
- Returning brain tumors could be detected earlier.
- It could be more convenient for patients who currently have an MRI scan every three months.