Role of miRNA and cancer stem cells in chemoresistance and pancreatic cancer treatment

, limiting the chance for com-plete excision of these tumors. Furthermore, prolonged treatment with chemotherapyresultsinmultidrugresistance.Inrecentyears,scientistsandphysicianshaveexpandedsignificant efforts to explain the underlying mechanism of chemoresistance forimproving both duration of survival and quality of life. The highly complex natureof drug resistance renders current single agent or multiple drug combinations ineffec-tive, leading to poor patient survival making pancreatic cancer one of the deadliestmalignancies. To date, a variety of distinct and disparate molecular mechanismshave been suggested including the role of ATP binding cassette (ABC)-transporters,increased DNA repair and dysregulation of the apoptotic machinery, enhanced cyto-plasmic inactivation of drug metabolites and overexpression of oncogenes or down-regulation of tumor suppressor genes. Despite these advances, our understanding ofchemoresistance in pancreatic cancer is fragmentary and incomplete. Recent studiesin our lab and by other groups