SSEA-4, a sialic acid-containing glycolipid, is recognized as a specific marker for pluripotent stem cells, and is reportedly a useful marker for the detection of CSCs. Furthermore, SSEA-4 expression has been associated with the remodeling of gastrointestinal cancer cell lines including those in esophageal, stomach, colorectal, liver, pancreatic, and cholangiocellular cancer. In addition, SSEA-4 expression is positively associated with malignant behavior in breast cancer and glioblastoma.