Researchers at the Johns Hopkins Kimmel Cancer Center have developed a groundbreaking test that can detect brain cancers using just a small sample of cerebrospinal fluid (CSF), potentially reducing the need for invasive diagnostic procedures.
The multi-analyte test, called CSF-BAM (cerebrospinal fluid–B/T cell receptor, aneuploidy and mutation), was designed to measure multiple biological markers at once—including tumor-derived DNA, chromosomal abnormalities, and immune cell receptor sequences. By combining these signals, the test achieved over 80% sensitivity and 100% specificity, according to findings published August 25 in Cancer Discovery. That means it successfully identified brain cancers in the majority of cases while producing no false positives.
“This study highlights how much more information we can gain when we evaluate several analytes together,” said Chetan Bettegowda, M.D., Ph.D., Harvey Cushing Professor and Director of Neurosurgery at Johns Hopkins and a senior author of the study. “The ability to detect cancers with high specificity and also gain insight into the immune environment of the brain could be an important advance in the care of patients with brain tumors.”
Why It Matters
Brain cancer diagnoses often rely on invasive biopsies or uncertain imaging results. Researchers say CSF-BAM could provide a less risky alternative, especially in situations where standard tests are inconclusive or surgery isn’t possible.
“Many patients with brain lesions face invasive diagnostic procedures to confirm a cancer diagnosis,” noted Christopher Douville, M.D., assistant professor of oncology and co-senior author. “A tool like this could help us make better-informed decisions about who really needs a biopsy and who doesn’t.”
The study analyzed 206 CSF samples from patients with a range of brain cancers, including high-grade gliomas, medulloblastomas, metastases, and central nervous system lymphomas. Beyond cancer detection, the test also identified distinct patterns in immune cell populations between cancerous and noncancerous cases, offering additional context that may help clinicians understand both disease presence and the brain’s immune response.
A Step Toward Personalized Care
Because it can both detect cancer and provide immune system insights, CSF-BAM could play a dual role in diagnosis and treatment planning. Researchers believe this type of test could guide a more personalized approach to care, tailoring interventions to each patient’s unique biology.
The project was supported by grants from the National Cancer Institute (NCI), along with funding from organizations such as Alex’s Lemonade Stand Foundation, the Lustgarten Foundation, and Swim Across America.
While more validation is needed before CSF-BAM could be adopted widely in clinical practice, the results offer a promising step toward safer, more accurate brain cancer diagnostics.
