MicroRNA in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies. Patients with PDAC are often asymptomatic, and many have lymph node and distant metastases as well as vessel invasion upon diagnosis. Surgery and current chemotherapy have limited efficacy for improving prognosis, which accounts for overall median survival of 8.6 months and a 9.7% 5-year survival rate. MicroRNAs (miRNAs) are attracting increasing attention because of their association with tumour progression. At least 50% of miRNAs that are aberrantly expressed in tumours have important roles as post-transcriptional regulators and exhibit oncogenic or tumour suppressive activities by directly binding to their target messenger RNAs. Various techniques are available to identify miRNAs that are differentially expressed in cancerous vs normal tissues. In this review, we summarise the miRNA profiles of normal pancreatic tissue and cancer tissue of patients with PDACs and characterise the expression of miRNAs associated with tumour progression. Further, we highlight the target genes and signalling pathways of miRNAs that are aberrantly expressed in PDACs. This knowledge may lead to the development of preventive and therapeutic strategies for treating this deadly disease.