Exploration of IDO1 as a Therapeutic Target in Pediatric Central Nervous System Tumors

The immune system can suppress and even eradicate tumor growth, but some central nervous system (CNS) tumors have been linked to immune-evasive strategies due to their continued progression. The capability of the immune system to recognize and inhibit the growth of cancer is dependent on its ability to recognize the variety of genetic and epigenetic (non-gene) variations that characterize tumors. A consistent feature of adult glioblastoma is the presence of immunosuppressive regulatory T cells (Treg). These T cells impair a patient’s anti-glioblastoma immune response and the expression of the enzyme indoleamine 2,3 dioxygenase 1 (IDO1). Further data suggests that IDO1 is a high value target for immunotherapeutic consideration in adult glioma. However, whether these findings translate to pediatric brain tumors has yet to be explored. This project aims to determine the level of IDO1 expression in pediatric central nervous system tumors, specifically focusing on low grade glioma, high grade glioma, medulloblastoma and ependymoma. The Children’s Brain Tumor Network contributed 16 high-grade glioma samples, 20 low-grade glioma samples, 20 medulloblastoma samples, 18 ependymoma samples and 12 DIPG samples to this project.