TBIO-04. A CENTRALIZED MOLECULAR DIAGNOSTIC SERVICE FOR PEDIATRIC BRAIN TUMORS IN JAPAN

Abstract

Molecular tests have now become an essential part of clinical management of pediatric brain tumor patients. We have established a central diagnosis system for pediatric brain tumors in Japan to provide standardized molecular diagnostic service. Tumor specimen are accepted from centers participating Japan Children's Cancer Group (JCCG). The JCCG Datacenter at National Center for Child Health and Development (NCCHD) manages all patients' specimen and information. Histology is centrally reviewed at Gunma University Hospital. Molecular tests are performed at either Osaka National Hospital (medulloblastoma), Gunma University Hospital (ETMR) or National Cancer Center (all the others). Medulloblastomas are classified by expression profiling using the nanostring technology, and mutations of CTNNB1, TP53 and TERT determined. Gliomas are examined for mutations of BRAF, H3F3A, HIST1H3B, FGFR1, IDH1/2 and TERT using pyrosequencing, as well as for BRAF fusion by RT-PCR as necessary. Supratentorial ependymomas are examined for the presence of RELA fusion by RT-PCR, and posterior fossa ependymomas are classified as PFA or PFB by DNA methylation analysis. Those tumors negative for the routine analyses may be subjected to RNA sequencing or targeted sequencing for 93 genes known to be mutated in brain tumors. As of August 2017, over 200 tumors have been molecularly diagnosed and the integrated diagnosis reported to each center. Our system is affordable utilizing minimum amount of high throughput technologies, and will hopefully improve the standard of diagnosis for pediatric brain tumors.