Pancreatic ductal adenocarcinoma (PDAC) has the worst prognosis among all cancers due to latestage diagnosis, limited detection and treatment methods. MiRNAs are post-transcriptional regulators, recently reported to have numerous functions, including modulation of cellular differentiation, proliferation, and apoptosis, Several tumor suppressors, such as PTEN, TPM1, and PDCD4 were identified as miR-21 targets. MiR-21 is stable in both tissues and plasma, disease-specific and therefore it appears to be a promising biomarker for benign and malignant diseases of pancreas. Current evidence suggests that miR-21 overexpression is associated with shorter overall survival, higher rate of liver and regional lymph nodes metastases.