[Monitoring minimal residual disease in pediatric acute myeloid leukemia]

The event-free survival rate for childhood acute myeloid leukemia (AML) is approaching 60%, owing to the use of intensive chemotherapy, optimal indication of hematopoietic stem cell transplantation, and advances in supportive care. For further improvement, the development of more definitive risk stratification system and introduction of more effective treatment options are necessary. Recently, much attention has been drawn on minimal residual disease (MRD) that is considered a strong prognostic factor for children with AML. Recent studies from the United States and Europe have shown the prognostic impact of FCM-based MRD detection and it is already used for risk stratification in modern AML protocols. Myeloid leukemia in Down's syndrome (ML-DS) has unique characteristics, and ML-DS children are recently being treated separately from non-DS AML children with less intensive treatment. It has been shown that relapsed and refractory cases of ML-DS are difficult to treat; however, no universal prognostic factor has been found yet. In order to determine accurate methods for identifying a subgroup with poor prognosis, an attempt to analyze the role of MRD had been examined in the JPLSG AML-D11 study. In this study, the MRD by FCM and targeted deep sequencing for GATA1 after initial induction therapy were significant prognosis factors for predicting relapse.