Recent development of massive parallel-sequencing technology has revealed the genetic basis of pediatric T-cell acute lymphoblastic leukemia (T-ALL). However, epigenetic profiles of T-ALL, such as DNA methylation, have not been well characterized. To describe the epigenetic landscape of T-ALL, we investigated DNA methylation profiles of 79 cases with pediatric T-ALL by using the EPIC methylation array, which allowed us to perform more profound analyses, including the OpenSea region. Moreover, we conducted combined analyses of methylation data using our previous expression and mutation data. Based on DNA methylation profiles, pediatric T-ALL was clustered into four distinct subtypes, which exhibited remarkable association with genetic signatures and expression features, as well as profiles of normal T-cell development. Furthermore, our study revealed the importance of methylation status at binding sites of polycomb-repressive complex components and transcription factors, such as SPI1, in the classification of pediatric T-ALL based on DNA methylation status. These results might be helpful in the development of new therapeutic strategies for pediatric T-ALL.
Keywords: Epigenome; Methylation; Pediatric leukemia; T-cell acute lymphoblastic leukemia.