Phase 1 Study of Locoregional Injections of Ex Vivo Expanded Natural Killer Cells

This early-phase study is testing whether natural killer (NK) cells — immune cells taken from donors, grown in large numbers in a lab, and then injected directly into or around a brain tumor — are safe and can help fight brain cancers that have come back or stopped responding to treatment. **You may be eligible if:** - You have a brain tumor (confirmed by biopsy) that has come back, progressed, or is not responding to treatment - Your cancer is not a diffuse midline glioma or DIPG type - Your surgeon believes you are a candidate for placement of a small device (Ommaya reservoir) directly in or near the tumor - You meet performance and health criteria set by the study team **You may NOT be eligible if:** - You have diffuse intrinsic pontine glioma (DIPG) or diffuse midline glioma - The resection cavity or tumor is too small for safe device placement - You have significant other health conditions preventing participation Talk to your doctor to see if this trial is right for you.