ALDH1A1 and pancreatic neoplasm: In pancreatic cancer, several markers have been used to identify CSCs, such as epithelial cell adhesion molecule (EpCAM, also known as epithelial-specific antigen, or ESA) [8], CD24 [9], CD44 [10, 11], CD133 [12, 13], CXCR4 [14], aldehyde dehydrogenase 1 (ALDH1) [15, 16] and combinations of these markers [17–19].