Particularly, it has been shown that pancreatic cancer stem/progenitor cells expressing stem cell-like markers such as CD133, CD44 and ABCG2 multi-drug transporter may be more resistant to oxygen and nutrient deprivation, irradiation and gemcitabine treatment than the bulk mass of differentiated pancreatic cancer cells [12, 51, 52, 63, 275]. The gene discussed is ABCG2; the disease is pancreatic neoplasm.