ABCG2 and pancreatic neoplasm: We next examined the expression of stem cell markers (CD133+CD44+CD24+ESA+), pluripotency maintaining factors (Nanog), signaling molecule (Notch-1) and drug resistant genes (MDR1 and ABCG2) in human normal pancreas, primary pancreatic cancer cells, and CSCs by q-RT-PCR (Fig. 1I).