NT5E and pancreatic neuroendocrine tumor: More recently, Katsuta et al. [36] identified CSCs basing on ALDH activity in pancreatic neuroendocrine tumor (pNET) clinical specimens and cell lines, and found that CD73 was overexpressed in ALDHhigh cells, and inhibition of CD73 significantly attenuated in vitro sphere formation and cell motility, as well as in vivo tumor growth for ALDHhigh cells.