RNAseq of a cohort series of 18 pediatric MBs in Taiwan

Background: Since 2016, a project for molecular diagnosis of childhood medulloblastoma (MB) was initiated in Taiwan. We aimed to integrate molecular classification, molecular and clinical risk factors, somatic mutations, and phenotypic traits for up to date adaptive care. Method: 18 MBs in children with frozen tumor tissue were assembled. Clinical data were retrieved. RNA-Seq and DNA methylation array data were generated. Molecular subgrouping and molecular-clinical correlation were performed. Subgroup-based risk stratification included an adjusted Heidelberg risk stratification scheme were defined and evaluated. We selected 51 genes for somatic variant calling using RNA-Seq. Relevant phenotypic traits were defined for the linkage of genetic predisposition. Results: Four core molecular subgroups (WNT, SHH, Group 3, and Group 4) were identified. Genetic backgrounds of metastasis at diagnosis and extent of tumor resection were observed. The overall survivals of the adjusted Heidelberg scheme matched with the definition of each risk subgroups. Somatic mutations in DNA damage response were detected. Conclusion: The findings of this study provide valuable information for adaptive risk stratified treatment and personalized care of childhood MBs in our cohort series and in Taiwan. mRNA profiles of a cohort series of 18 pediatric MBs in Taiwan were generated by RNAseq, using Illumina Nextseq 500.