피검사로 뇌종양 진단

 

https://medicalxpress.com/news/2020-06-brain-tumors-blood.html

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.

Dr. Zadeh worked with Senior Scientist Dr. Daniel De Carvalho at Princess Margaret Cancer Centre, who is a world leader in the field of cancer epigenetics applied to early detection, classification and novel therapeutic interventions.

Dr. De Carvalho's lab specializes in 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.

Dr. De Carvalho 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, his team was able to develop a highly sensitive and accurate test to detect and classify multiple solid tumors.

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, says Dr. Zadeh. 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, we now have a new, non-invasive way of detecting and discriminating between common brain tumors—something which was long thought impossible. This really is a tour de force," 

 

liquid에서 ctDNA 검출하는 것에 대한 것이 좀 보이는 것 같다.

 

reference

Nassiri, F et al. Detection and discrimination of intracranial tumors using plasma cell-free DNA methylomes. Nat Med (2020). doi.org/10.1038/s41591-020-0932-2