Conclusions
Available evidence strongly suggests that different cell types in pancreas are capable of undergoing transdifferentiation and dedifferentiation. Evidence also strongly supports the existence of stem cells in both the exocrine and endocrine pancreas. In the rat copper dificiency model, dormant stem cells present in the ductal and ductular system can be stimulated to proliferate and they have been shown to clearly differentiate into hepatocytes, a cell type not normally present in pancreas. Putative stem cells derived from the pancreas of rats after prolonged copper deficiency, can be easily grown in culture, but there is need to identify appropriate signals and defined culture conditions that can direct the in a reproducible fashion to differentiate into a specific cell type such as β-cells or liver cells. When these specific signaling molecules are identified pancreatic stem cells will be a source of an unlimited supply of self-renewable cells for transplantation. Although, the existence of pancreatic stem cells is being increasingly accepted and their multidirectional differentiation potential is recognized, their role, if any, in pancreatic cancer development remains to be clarified and investigated.