The discovery focuses on brain tumors known as IDH-mutant astrocytomas. These tumors can evolve over time, becoming more aggressive and increasingly difficult to treat.
Measuring at two points in time
The research teams at Amsterdam UMC and Erasmus MC analyzed tumor tissue collected from patients at two stages: when the tumor was first diagnosed and when it later recurred. They examined a wide range of tumor features, including genes, gene activity, and methylation—chemical markers on the DNA. Their analyses revealed that recurrent IDH-mutant astrocytomas become genetically less stable and show signs of faster cell growth.
The researchers also uncovered the mechanism driving this accelerated growth. They found that methylation - the chemical markers on the DN - decreases over time, particularly in tumors that return in a more aggressive form. This loss of methylation could therefore serve as an important predictor of how dangerous a tumor is and how long a patient is likely to survive.
An aggressiveness scale
Based on these findings, the researchers developed an “aggressiveness scale” that assigns a score to each tumor. This score helps physicians better estimate the severity of the disease and make more evidence-based treatment decisions.
“This score proved effective not only in our own patients, but also in large, independent patient cohorts,” say Wies Vallentgoed of Amsterdam UMC and Pim French of Erasmus MC. “Our study introduces a new, scientifically validated way to grade brain tumors, which can guide treatments more precisely and allow outcomes to be predicted with greater accuracy.”
Varying degrees of severity
IDH-mutant astrocytomas are brain tumors that typically occur in younger adults and belong to the group of diffuse gliomas. They carry a mutation in the IDH gene and vary in severity, classified as grade 2, 3, or 4 (with grade 4 being the most aggressive). These tumors infiltrate surrounding brain tissue, making them difficult to remove completely, even when scans suggest they are relatively well defined. After surgery, they almost always recur and often progress to a higher grade.
The team’s findings have been published in Nature Cancer.
Source text: Erasmus MC
Sources images: Shutterstock and Erasmus MC