Malignant brain tumors are the most common cause of cancer-related death in children. The current standard of care treatment is often associated with lifelong cognitive and motor deficits and is almost inevitably followed by disease recurrence. Therapiesthat specifically and efficiently target tumor cells and minimize toxicity to normal cells are thus critical to the next generation of interventionsthat promise improved clinical outcomesfor children affected by these deadly diseases.

The gut microbiome plays a critical role in modulating the immune response, influencing outcomes of allogeneic transplantation, a life-saving treatment for relapsed/refractory leukemia and lymphoma. However, this treatment comes with significant complications that can limit is efficacy. Understanding and leveraging the immunomodulatory potential of the microbiome is crucial for optimizing cancer therapy outcomes. However, the mechanisms underlying the microbiome's influence on outcomes post-transplant, especially in pediatric patients, remain insufficiently understood.