CD44 and cancer: These pancreatic CSCs show the following features: (a) cells are triple-positive for CD44, CD24 and EpCAM; (b) they have a high tumorigenic activity, developing tumors from implants of as few as 100 CSCs, displaying a 100-fold enhanced tumorigenic potential as compared to the parental pancreatic cancer population from which they derive; (c) they form CSC pancreatic cancer spheroids rapidly under a serum-free special cancer stem culture medium.