ALDH1A1 and malignant colon neoplasm: After co-culturing IL-17-producing Tregs isolated from colon cancer patients’ tumors with Sphere cells derived from normal human bone marrow, Sphere cells exhibited increased expression of multiple colon cancer-initiating cell-related phenotypes, such as CD133, CD44s, CD166, epithelial cell adhesion molecule (EpCAM), and aldehyde dehydrogenase 1 (ALDH1).