In a new study, researchers found a simple but highly sensitive blood test could accurately diagnose and classify different types of brain tumors.
The finding describes a non-invasive and easy way to classify brain tumors.
It can result in more accurate diagnosis, less invasive methods, and better treatment planning for patients, in the future.
The research was conducted by a team at the Krembil Brain Institute and elsewhere.
A major challenge in treating brain cancers is the accurate diagnosis of different types of brain cancers, and tumors ranging from low grade—which can look almost normal under a microscope—to aggressive tumors.
Cancer grades are used to determine prognosis and assist in treatment planning.
Current methods to diagnose and establish the subtype of brain cancer based on molecular information rely upon invasive surgical techniques to obtain tissue samples, which is a high-risk procedure and anxiety-provoking for patients.
The ability to diagnose and classify the type of brain tumor without the need for a tissue sample is revolutionary and practice-changing. In some cases, surgery may not even be necessary.
In the study, the team focused on a type of epigenetic modification called DNA methylation, which plays an important role in the regulation of gene expression (turning genes on or off) in cells.
In cancer cells, DNA methylation patterns are disrupted, leading to unregulated cancer growth.
The team has previously developed a DNA methylation-based liquid biopsy approach to profile hundreds of thousands of these epigenetic alterations in DNA molecules circulating in the blood. These fragments are called circulating tumor DNA or ctDNA.
Combining this new technology with machine learning, the team was able to develop a highly sensitive and accurate test to detect and classify multiple solid tumors.
They used this approach in the challenging application of intracranial brain tumor classification.
The clinicians and scientists tracked the cancer origin and type by comparing patient tumor samples of brain cancer pathology, with the analysis of cell-free DNA circulating in the blood plasma from 221 patients.
Using this approach, they were able to match the circulating plasma ctDNA to the tumor DNA, confirming their ability to identify brain tumor DNA circulating in the blood of these patients.
Then, using a machine learning approach, they developed a computer program to classify the brain tumor type based solely on the circulating tumor DNA.
Prior to this, it was not thought possible to detect any brain cancers with a blood test because of the impermeable blood-brain barrier.
This barrier exists between the brain’s blood vessels and its tissue, protecting the brain from any toxins in the blood.
But because this test is so sensitive in picking up even small amounts of highly specific tumor-derived signals in the blood, doctors now have a new, non-invasive way of detecting and discriminating between common brain tumors—something which was long thought impossible.
Another team from the Dana-Farber Cancer Institute at Harvard University shows the same blood test can accurately identify kidney cancer from circulating cell-free DNA obtained either from plasma or from urine.
One author of the study is Dr. Gelareh Zadeh, Medical Director of the Krembil Brain Institute.
The study is published in Nature Medicine.
Copyright © 2020 Knowridge Science Report. All rights reserved.
