MicroRNAs (miRNAs) were reported to be associated with cancer progression and carcinogenesis. MiRNAs are small, highly conserved, small non-coding RNA molecules, consisting of 18-25 nucleotides that control gene expression at the post-transcription level. By binding to complementary binding sites within the 3' untranslated region (3'UTR) of target messenger RNAs (mRNAs), inhibiting translation or promoting degradation of mRNAs. MicroRNAs not only play an important part in regulating gene expression but also controlling diverse physiological and pathological processes. Similarly, several studies have demonstrated that miRNAs have been involved in regulating various biological processes, including apoptosis, proliferation, cellular differentiation, metabolism, signal transduction, and carcinogenesis. MiRNA-139, which is located in 11q13.4 and has anti-oncogenic and antimetastatic activity in humans, meanwhile, was identified to be downregulated in previous studies. However, based on the pathogenetic relationship between cancer and the role of miR-139-5p in tumorigenesis, we consider that miR-139-5p may be the candidates to serve as promising biomarkers with sufficient sensitivity and specificity for the diagnosis of cancer in a clinical setting; moreover, it would offer a new safe and effective way in further molecular targeting cancer treatment, as well as improving overall survival of patients.