Medical researchers from the University of Cambridge have developed two new tests able to detect the presence of glioma, which is a type of brain tumor. The tumor can be detected using the newly developed tests in the urine or blood plasma of the patient. Researchers note that detecting glioma using urine is the first test of its kind in the world.
The researchers are clear in their paper about the new tests that they are in the early stages of trials, and only a small number of patients have been analyzed. Despite the small sample size, the group says the results are promising. The results suggest that in the future, tests can be used by doctors to monitor patients at risk of brain tumors.
Being able to monitor the condition via blood tests are urine tests is much more convenient than having an MRI every three months, which is currently the standard method of testing. While some brain tumors can be removed, the likelihood of tumors returning can be high. With the high incidence of recurrence, people with tumors that have been removed from the brain are monitored with an MRI every three months, followed by a biopsy.
Because those tests are so complicated, blood tests for detecting different cancer types are a significant focus of research. There are some cancer-detecting blood tests in use clinically. They are typically based on finding mutated DNA produced by tumor cells when they die, known as cell-free-DNA. However, detecting cell-free-DNA in brain tumors is difficult because of the blood-brain barrier separating the blood from the cerebral spinal fluid surrounding the brain and spinal cord.
That barrier prevents the passage of cells and other particles outside or into the brain. Researchers on the project worked on two approaches in parallel to overcome the challenge of detecting brain tumor cell-pre-DNA. The first works for patients that had a glioma removed and biopsied previously. Researchers designed a tumor-guided sequencing test to look for mutations found in the tumor tissue within the cell-free-DNA in the patient’s urine, cerebrospinal fluid, and blood plasma.
The team had eight patients with suspected brain tumors based on MRIs included in their study. Samples were taken at their initial brain tumor biopsies along with cerebrospinal fluid, blood, and urine samples. When they knew what DNA strand to look for, the researchers found it possible to find mutations even in tiny amounts of cell-free-DNA found in blood plasma and urine. The test detected cell-free DNA in seven of eight CFS samples, ten out of 12 plasma blood samples, and ten out of 16 urine samples.