Medulloblastoma (MB), the most common form of pediatric brain malignancy, has a low frequency of oncogenic mutations but pronouncedly abnormal DNA methylation changes. Epigenetic analysis of circulating cell-free tumor DNA (ctDNA) by liquid biopsy offers an approach for real-time monitoring of tumor status without tumor dissection. In this study, we identified 6598 differentially methylated CpGs in both MB tumors and the ctDNA isolated from matched cerebrospinal fluid (CSF) compared with normal cerebellum, which could be used to detect MB tumor occurrence and determine its subtype....…Medulloblastoma (MB), the most common form of pediatric brain malignancy, has a low frequency of oncogenic mutations but pronouncedly abnormal DNA methylation changes. Epigenetic analysis of circulating cell-free tumor DNA (ctDNA) by liquid biopsy offers an approach for real-time monitoring of tumor status without tumor dissection. In this study, we identified 6598 differentially methylated CpGs in both MB tumors and the ctDNA isolated from matched cerebrospinal fluid (CSF) compared with normal cerebellum, which could be used to detect MB tumor occurrence and determine its subtype....WW…