Low miR-34c expression is associated with poor outcome in de novo acute myeloid leukemia.
INTRODUCTION
MicroRNA-34c (miR-34c) has been found to play important roles in tumorigenesis. However, little is known about miR-34c expression and the impact on prognosis in acute myeloid leukemia (AML).


METHODS
Real-time quantitative PCR (qRT-PCR) was performed to analyze the status of miR-34c expression in 122 patients with de novo AML and 62 normal controls.


RESULTS
MiR-34c expression in AML was significantly downregulated compared to controls (P < 0.001). Receiver operating characteristic curves (ROC) indicated the distinguishing value of miR-34c for discriminating whole-cohort AML, non-M3 AML, and cytogenetically normal AML (CN-AML) patients from healthy controls. No significant differences were found between low miR-34c-expressing and high miR-34c-expressing patients in age, sex, hemoglobin, platelet count, percentage of blasts in bone marrow (BM), WHO classifications, karyotypes, and eight gene mutations, but low miR-34c cases had higher white blood cells (WBC) than high miR-34c cases (P = 0.035). MiR-34c low-expressed patients had similar rates of complete remission (CR) as miR-34c high-expressed patients in whole-cohort AML, non-M3 AML, and CN-AML patients (P = 0.347, 0.314 and 0.167, respectively). Kaplan-Meier analysis indicated that patients with low miR-34c level had markedly shorter overall survival (OS) time in whole-cohort AML, non-M3 AML, and CN-AML patients (P = 0.033, 0.024 and 0.001, respectively). Furthermore, multivariate analysis confirmed that low miR-34c expression was an independent risk factor not only in whole-cohort AML (P = 0.040) but also in non-M3 AML (P = 0.015) and CN-AML patients (P = 0.021).


CONCLUSIONS
Our findings indicate that low miR-34c level is a novel promising biomarker in predicting prognosis in patients with de novo AML.