Abstract

MicroRNAs (miRNAs) are small non-coding RNAs which regulate key cellular processes through a negative post-transcriptional regulation of their target mRNAs. They can act either as oncogenes or as tumor suppressors or as both, depending on the specific tissue expression. Oncogenic miRNAs act directly on mRNAs from genes with pro-apoptotic or anti-proliferative roles. Conversely, tumor-suppressor miRNAs repress the expression of genes with oncogenic functions. Deregulation of many of these miRNAs has been associated with tumorigenesis in various cancers and recent studies have shown evidences of abnormal miRNA expression in gallbladder cancer. Here, we review our current understanding of the expression changes in tumor-suppressor miRNAs (miR-1, miR-145, miR-135a-5p, miR-26a, miR-34a, miR-335, miR-130a and miR-218- 5p) and oncogenic miRNAs (miR-155, miR-20a and miR-182) and its implication in the pathogenesis of gallbladder cancer and their potential as diagnostic and prognostic markers.