['MicroRNA-100 (miR-100), a small noncoding RNA molecule, acts as a tumor suppressor or an oncogene in different cancers. The aberrant expression of this microRNA has been demonstrated as a frequent event in adult patients with acute myeloid leukemia (AML), but little is known for pediatric AML. The aim of this study was to investigate the expression and clinical significance of miR-100 in pediatric AML.', 'The expression levels of miR-100 in bone marrow mononuclear cells were detected by real-time quantitative polymerase chain reaction in a cohort of 106 patients with de novo pediatric AML. The prognostic values of miR-100 in pediatric AML were also analyzed.', 'Compared with normal controls, upregulation of miR-100 in the bone marrow of pediatric AML patients with statistically significant differences (P < 0.001) was found. The expression levels of miR-100 were found to be significantly higher in pediatric AML patients with extramedullary disease, with the French-American-British classification subtype M7, and with unfavorable day 7 response to induction chemotherapy (P = 0.008, 0.001 and 0.01, respectively). Moreover, both univariate and multivariate analyses revealed that miR-100 upregulation was associated with poorer relapse-free and overall survival in pediatric AML patients.'] Does upregulation of microRNA-100 predict poor prognosis in patients with pediatric acute myeloid leukemia?