PATH-07. Diagnostic and therapeutic value of cerebrospinal fluid biopsy in pediatric brain tumors

BACKGROUND: The application of cerebrospinal fluid (CSF) biopsy in brain tumors is valuable. This paper further explores the diagnostic and therapeutic value of CSF biopsy in pediatric brain tumors. METHODS: In this study, children with primary brain tumor aged ≤18 years old in Guangdong Sanjiu Brain Hospital were enrolled．CSF next-generation sequencing (NGS) tests were required for all included patients. The genetic mutations in these children were analyzed. RESULTS: A total of 12 pediatric brain tumors who underwent CSF NGS were included in this study. 9 patients were brainstem glioma and 3 were pilocytic astrocytoma. The mutated genes were detected in 67% (8/12) patients by CSF NGS. In brainstem glioma, the rate was 67% (6/9), and the most common genes were H3F3A (5/6, 83%) and TP53 (5/6, 83%). Other detected genes included EGFR, CDK4 and NF2. H3F3A mutation is of great significance for the diagnosis and treatment of brainstem glioma, and CDK4 and EGFR are valuable for the treatment. In pilocytic astrocytoma, the deteaction rate was 67% (2/3), and the genes included KIAA1549-BRAF fusion, FGFR1 and PTPN11 mutations. KIAA1549-BRAF fusion is of great value in the diagnosis and treatment of pilocytic astrocytoma, and FGFR is valuable in the treatment. CONCLUSIONS: Fluid biopsy of CSF for pediatric brain tumors may be an important supplement to histological diagnosis, especially when histopathology is not available. The results are significant for the diagnosis and treatment of pediatric brain tumors.