Characterization of Circulating and Tumor-infiltrating Immune Cells in Malignant Brain Tumors

This study collects blood and tissue samples from people with malignant (cancerous) brain tumors who are having surgery. Researchers want to better understand the immune cells that circulate in the blood versus those that are found inside the tumor itself. This could help scientists develop better immune-based treatments for brain cancer in the future. **You may be eligible if...** - You are 18 or older - You have been diagnosed with a primary or secondary malignant brain tumor - You are already scheduled to have brain surgery, a biopsy, or radiosurgery - You are able to give informed consent **You may NOT be eligible if...** - You do not meet the inclusion criteria above Talk to your doctor to see if this trial is right for you.