RNA-seq of PBMCs to investigate peptide vaccine immunotherapy biomarkers and response patterns in pediatric gliomas. RNA-seq of PBMCs to investigate peptide vaccine immunotherapy biomarkers and response patterns in pediatric gliomas

Low-grade gliomas (LGGs) are the most common brain tumor of childhood. Children with LGGs are ideal candidates for immunotherapy due to slow tumor growth, and as these children are otherwise healthy, and often have intact immune systems. We recently reported in an early phase clinical trial that vaccine treatment elicited strong biologic responses in LGG patients, compared with our experience in adult and pediatric high-grade brain-stem and non-brain stem gliomas. Additionally, we observed radiographic responses of stable disease (n=7), partial response (n=3), and complete response (n=2) following therapy. These remarkable results prompted us to initiate a phase II trial utilizing this strategy in pediatric LGGs. In order to identify potential peripheral response patterns in each response group, we performed Illumina RNA-sequencing on PBMCs samples (n=54), collected either prior to treatment or at multiple time points following treatment.