AI Breakthrough: Liquid Biopsy Now Detects Pediatric Brain Tumors with 92% Accuracy
Imagine being able to diagnose and monitor brain cancer in children without invasive surgery—just a simple fluid sample from the cerebrospinal fluid. This breakthrough is now a reality thanks to groundbreaking research from St. Jude Children's Research Hospital.
A Revolutionary New Diagnostic Tool
St. Jude scientists have developed M-PACT (Methylation-based Predictive Algorithm for CNS Tumors), an AI-powered system that can classify pediatric brain tumors using tiny amounts of circulating tumor DNA found in cerebrospinal fluid. Published in Nature Cancer, this innovation represents a major leap forward in pediatric neuro-oncology.
"M-PACT is about taking liquid biopsy to another level in pediatric neuro-oncology and applying the technology across many different clinical scenarios," said Dr. Paul Northcott, corresponding author and Director of St. Jude's Center of Excellence in Neuro-Oncology Sciences (CENOS).
How M-PACT Works
Traditional brain tumor diagnosis requires invasive tissue biopsies, which can be risky for young patients. Liquid biopsies offer a noninvasive alternative by testing body fluids that contain cancerous material, including circulating tumor DNA (ctDNA). However, previous attempts faced significant limitations due to the extremely small amounts of ctDNA available from pediatric brain tumors.
M-PACT overcomes this challenge by using a deep neural network trained on more than 5,000 DNA methylation profiles across roughly 100 tumor entities. The system identifies cancer's unique "fingerprint"—abnormal DNA methylation patterns that act as molecular signatures for specific tumor types.
"We reversed the usual flow and designed M-PACT for circulating tumor DNA itself with applicability to tissue, instead of the other way around," explained co-first author Katie Han, a PhD student at St. Jude.
Unprecedented Accuracy Rates
The results are remarkable:
- 92% accuracy in classifying embryonal central nervous system tumors (benchmarking cohort)
- 88% accuracy in the validation cohort
- Ability to detect tumor relapse years after initial treatment
- Differentiation between true relapse and secondary malignancies
These performance metrics represent a significant improvement over existing diagnostic methods for pediatric brain tumors.
Beyond Diagnosis: Treatment Monitoring and Surveillance
M-PACT's capabilities extend far beyond initial diagnosis. The system can track disease evolution during therapy, identify when cancer is becoming more aggressive, and determine treatment response without requiring additional invasive procedures.
"If a tumor reoccurs years later, M-PACT can reliably determine whether it's a true relapse or a second malignancy," Dr. Northcott explained.
Peeking into the Cancer Microenvironment
One of M-PACT's most powerful features is its ability to analyze not just tumor cells, but also the surrounding microenvironment. The system can identify noncancerous cell types contributing to the tumor ecosystem, including T cells and B cells.
"Most DNA in cerebrospinal fluid is from something else, the 'negative space' of the tumor, which we previously ignored," said co-first author Dr. Kyle Smith. "Now we can predict what fraction comes from T cells, B cells, or other sources."
This capability opens new questions about how cancers manipulate normal cells and creates opportunities to monitor disease evolution when tissue sampling isn't typically done.
Global Collaboration Behind the Breakthrough
The M-PACT development relied on international partnerships between St. Jude investigators and scientists at:
- Hopp Children's Cancer Center Heidelberg (KiTZ)
- German Cancer Research Center (DKFZ)
- Multiple other participating institutions worldwide
"Our study is a prime example of what can be accomplished when we approach science as a team and bring together complementary skills and expertise to achieve a common goal," Dr. Northcott noted.
Future Applications Beyond Brain Tumors
While M-PACT was designed for pediatric brain tumors, the robust framework offers broad potential applications. The technology could be adapted for other solid tumors and hematological malignancies affecting children.
"Although we applied this to pediatric brain tumors, it will clearly be useful in other solid tumors and hematological malignancies as well," Dr. Northcott said. "The informatics will need to grow to classify the full scope of cancer types diagnosed in children, but we've developed something quite powerful that is likely to be more broadly adopted in the community."
What This Means for Families
For families facing pediatric brain tumor diagnoses, M-PACT represents hope for:
- Less invasive diagnostic procedures
- More accurate tumor classification
- Better treatment monitoring
- Earlier detection of relapse
- Reduced need for repeated surgeries
The Road Ahead
As with any medical breakthrough, M-PACT will undergo additional validation studies before widespread clinical adoption. However, the technology's success in both benchmarking and validation cohorts suggests it could become a standard tool in pediatric neuro-oncology within the next few years.
The research was supported by multiple organizations including the National Cancer Institute, St. Baldrick's Foundation, the Brain Tumor Funders' Collaborative, and American Lebanese Syrian Associated Charities (ALSAC).
Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals for diagnosis and treatment of medical conditions.
References
-
Smith, K.S., et al. (2026). M-PACT leverages cell-free DNA methylomes to achieve robust classification of pediatric brain tumors. Nature Cancer. DOI: 10.1038/s43018-026-01115-4. https://www.nature.com/articles/s43018-026-01115-4
-
St. Jude Children's Research Hospital. (2026). Classifying pediatric brain tumors by liquid biopsy using artificial intelligence. https://www.stjude.org/media-resources/news-releases/2026-medicine-science-news/classifying-pediatric-brain-tumors-by-liquid-biopsy-using-artificial-intelligence.html
-
The ASCO Post Staff. (2026). AI Tool Classifies Pediatric Brain Tumors via Liquid Biopsy. https://ascopost.com/news/february-2026/ai-tool-classifies-pediatric-brain-tumors-via-liquid-biopsy/
-
News Medical. (2026). M-PACT sets new standard for pediatric brain tumor diagnostics, treatment monitoring. https://www.news-medical.net/news/20260217/M-PACT-sets-new-standard-for-pediatric-brain-tumor-diagnostics-treatment-monitoring.aspx