Biomarkers of Brain Injury in Children With Brain Tumors

This study is looking at blood and fluid markers that can detect brain injury in children with brain tumors in Sweden. Researchers want to understand how radiation and other cancer treatments affect the developing brain by tracking these biomarkers over time. There are three groups: children receiving radiation, children receiving other treatments (no radiation), and healthy children for comparison. **You may be eligible if...** - You are a child aged 0–17 years old - You have been diagnosed with a primary brain tumor at a Swedish university hospital - You are being treated with or without radiation at Skandion Clinic or another hospital in Sweden - OR you are a healthy child aged 0–17 with no chronic illness (for the control group) **You may NOT be eligible if...** - Your tumor is only in the spinal cord - Your tumor has been classified as palliative (end-stage) from the start, such as certain brainstem tumors - You have a chronic disease requiring ongoing medication (control group only) - There are language barriers preventing you from giving informed consent Talk to your doctor to see if this trial is right for you.