Pancreatic cancer tumour initiating cells: the molecular regulation and therapeutic values

Pancreatic cancer is an aggressive solid tumour characterized by its local invasion, early metastasis and resistance to standard chemotherapy or radiation therapy. Tumour initiating cells (TICs) are not only capable of self-renewal and differentiation, but also play an important role in multi-drug resistance, and thus become a popular topic in cancer research especially in pancreatic cancer. In this review, we summarize the current progress of TICs in tumourigenesis, various newly identified surface markers of pancreatic TICs, and the signalling pathways such as epithelial-mesenchymal transition, sonic hedgehog and Notch that regulate TICs. We also discuss the role which microRNA plays in TICs as well as its application in TIC-targeted therapy along with other approaches.