Acute myeloid leukemia (AML) is a heterogeneous disease with various pathogenesis, treatment responses and clinical outcomes. Personalized treatment according to individual patient risk could both improve patient survival and reduce treatment side effects. MicroRNAs are a class of small, non-coding RNAs that are derived from precursor RNAs processed by a protein complex containing Dicer and Drosha. They regulate gene expression post-transcriptionally through either mRNA degradation or translation inhibition. In AML, microRNAs are involved in hematopoietic cell differentiation, proliferation, and survival and can affect treatment responses and outcomes. In collaboration with prof. Eric Y. Chuang’s team at the Graduate Institute of Biomedical Electronics and Bioinformatics, prof. Hwei-Fang Tien and Wen-Chien Chou and the leukemia research team at the Division of Hematology, Department of Internal Medicine, comprehensively profiled microRNAs in 138 AML patients and found that high expression of hsa-miR-9-5p and hsa-miR-155-5p independently predicted poor prognosis, whereas high hsa-miR-203 tended to indicate a favorable outcome (Figure 1). They constructed a scoring system from the expression of these 3 microRNAs by considering the weight of each. The scores correlated with distinct clinical and biological features and outperformed single microRNA expression in prognostication. The power of this signature was validated by another independent AML cohort from the Cancer Genome Atlas (TCGA). Higher scores were associated with shorter overall survival (Figure 2) independent of other well-known prognostic factors, such as age, white blood cell counts, cytogenetics and molecular mutations. By analyzing mRNA expression profiles, they identified several cancer-related pathways that were highly correlated with the prognostic microRNA signature (Figure 3). This 3-microRNA scoring system is simple, powerful, and widely applicable for the risk stratification of AML patients. From a practical point of view, these three microRNAs can be analyzed by simple qPCR-based methods for each newly diagnosed AML patient, and the 3-microRNA risk score can be calculated. The procedures are inexpensive and fast and can be performed in a high-throughput manner to help clinicians choose the proper treatment for individual patients. Reference: Chuang MK, Chiu YC, Chou WC, Hou HA, Chuang EY, Tien HF: A 3-microRNA scoring system for prognostication in de novo acute myeloid leukemia patients. Leukemia 29: 1051-1059, 2015 Professor Hwei-Fang Tien, Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital hftien@ntu.edu.tw Reference Ming-Kai Chuang, Yu-Chiao Chiu, Wen-Chien Chou, Hsin-An Hou, Eric Yao-Yu Chuang, HweiFang Tien. (2015). A 3-microRNA scoring system for prognostication in de novo acute myeloid leukemia patients. Leukemia, 29, 1051-1059. DOI: 10.1038/leu.2014.333 Professor Hwei-Fang Tien Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital hftien@ntu.edu.tw Professor Wen-Chien Chou Department of Laboratory Medicine National Taiwan University Hospital wcchou@ntu.edu.tw