Each May, Brain Cancer Awareness Month highlights brain and other central nervous system cancers—some of the most complex and least understood. Despite recent advances, people with rare brain tumors still face delays in diagnosis, limited access to specialized care, and fewer treatment options when time matters most.
Diffuse midline glioma (DMG) is a rare brain tumor that is particularly difficult to diagnose and treat. Often located deep within the brain they are difficult if not impossible to remove surgically and are often driven by specific genetic changes that are distinct from those found in more common cancer types.
Standard tests like MRI scans and traditional pathology analysis give some information about tumor biology, but often don’t provide all the answers. Tumor molecular testing, which can be used to characterize tumor DNA and other unique biomarkers, can help physicians better understand tumor biology and guide treatment decisions. Without proper molecular testing, tumors may be misclassified or important molecular characteristics missed, which can result in less effective treatment and missed opportunities for clinical trials or molecular-targeted therapies.
Even though tumor tissue molecular testing is now considered part of standard care for brain tumor patients, access to the proper testing can vary across medical settings. For example, outside of major academic medical centers, advanced molecular testing may not be readily available. In addition, molecular testing results can take two to three weeks to return, but patients need to begin treatment right away, particularly in the case of malignant and aggressive tumors. Given this urgency, there is little room for delays.
Brain Cancer Awareness Month is an opportunity to highlight why early molecular testing is so important, especially for patients with rare brain tumors.
In DMG, the presence of a specific mutation, which is termed H3 K27M, can significantly impact tumor biology and patient response to treatment. Specifically, patients with the H3 K27M mutation tend to have shorter survival and poorer response to therapy, which has led the clinical and research community to seek more appropriate, molecular-targeted therapy for these patients. As a result, identifying this mutation in a DMG patient can now guide treatment decisions and determine eligibility for clinical trials, helping patients and families better understand their options and connect to the right care sooner.
Encouraging advances in surgical techniques now make it possible to collect tumor tissue from areas of the brain once considered too risky to biopsy. At the same time, improved molecular testing techniques can deliver meaningful insights from even very small brain tumor samples. Together, these advances are deepening our understanding of rare brain tumors like DMG, and helping drive the development of more targeted treatments for these patients.
One exciting area of progress is the ability to detect circulating tumor DNA (ctDNA) in cerebrospinal fluid— the fluid surrounding the brain and spinal cord. Known as a “liquid biopsy,” this approach may help doctors identify and track tumor changes without the need for additional surgeries. In the future, liquid biopsies could allow doctors to monitor how tumors respond to treatment while reducing risk and stress for patients.
While progress is being made to develop new and more effective treatment for rare tumors like DMG, more awareness is still needed. Patients and healthcare providers must understand how important molecular testing is, especially for identifying key mutations like H3 K27M to guide care decisions.
As research continues, molecular testing can help connect patients to the right treatments sooner, resulting in more personalized and effective care with fewer delays for patients and their families.
