Nakamura S, et al. - Whether tumor-derived fragmentary DNA, or circulating tumor DNA (ctDNA) could detect high-risk patients for relapse of acute myeloid leukemia and myelodysplastic syndrome (AML/MDS) after undergoing myeloablative allogeneic stem cell transplantation (alloSCT), was investigated in this study performed on 53 patients with AML/MDS. Findings revealed comparable associations of both mutation-persistence (MP) in bone marrow at 1 and 3 months post-alloSCT and corresponding ctDNA-persistence (CP) in the matched serum, with higher 3-year cumulative incidence of relapse rates. Based on the findings, ctDNA was found useful, for the first time, as a non-invasive prognostic biomarker in patients with AML/MDS, undergoing alloSCT.