Katrina O'Halloran, MD Ashley Margol, MD

Brain and spinal cord tumors remain among the leading causes of serious illness and death in children. Sequencing tumor DNA has helped researchers understand the genetic changes responsible for different cancers. One promising approach involves identifying tumor DNA in cerebrospinal fluid, commonly called spinal fluid, through a procedure known as a liquid biopsy.

This approach may provide valuable information for diagnosing tumors, evaluating how they respond to treatment, and estimating the risk of recurrence. For example, research has shown that detecting medulloblastoma DNA after completion of therapy can indicate an increased likelihood of relapse.

Children's Hospital Los Angeles has developed technology to perform liquid biopsies using cerebrospinal fluid. Early studies have successfully identified genetic alterations associated with several different tumor types, including medulloblastoma, ependymoma, atypical teratoid/rhabdoid tumors, diffuse midline glioma (including diffuse intrinsic pontine glioma), high-grade glioma, and lower-grade tumors such as pilocytic astrocytoma.

Building on these findings, the research team is studying repeated liquid biopsies in children diagnosed with embryonal tumors of the brain and spinal cord. Spinal fluid samples will be assessed at important stages of care: at diagnosis, throughout treatment, when therapy concludes, during follow-up surveillance, and if the tumor returns.

The test findings will be shared with each child's clinical team, giving physicians additional information that may help them adjust and personalize treatment decisions. In previous cases, liquid biopsy findings, considered alongside other clinical information, have already contributed to changes in treatment.

By making it possible to follow tumor-related genetic changes over time, this research aims to improve how pediatric brain and spinal cord tumors are monitored and treated, with the ultimate goal of improving outcomes for children facing these diseases.