Abstract: The Role of MicroRNA in Tumor Diagnosis and TreatmentChao LIANG, ZhaoxiaWANG1Correspondence to: ZhaoxiaWANG, E-mail: misswangzhaoxia@yahoo.com.cnDepartment of Clinical Medicine, The First Medical College of Nanjing Medical University, Nanjing 210029, ChinaThis work was supported by National Natural Science Foundation of China (No.30973477) and Natural Science Foundation of JiangsuProvince (No.BK2010590)Abstract Malignant tumor has been one of the three predominant causes of death and a major health problem facing all coun-tries. Accumulations of multiple-gene damages, gene mutations, and abnormal gene regulation resulting from their interactions lead totumor occurence. Over the past few years, experts have found that microRNAs, a family of non-coding small single-stranded RNA mol-ecules, are related to the oncogenesis, progression, diagnosis and treatment of tumors and can be used as a new type of biological tag intumor diagnosis and treatment. The role of microRNAs in diagnosis and treatment of various tumors was reviewed in this article.Keywords MicroRNA; Cancer; Diagnosis; Therapy