Clone STE-1-89-11.5 reacts with the human leucine-rich repeat-containing G-protein-coupled receptor (LGR) LGR5 but not with its close homologues LGR4 or LGR6. LGR5 associates with Wnt-receptors and act as R-spondin receptor thereby playing a central role in the modulation of Wnt/β-catenin signaling in normal and neoplastic stem cells. Initially described as a highly specific marker for stem cells in the small intestine, colon, hair follicle, stomach, and during kidney development, LGR5 positive cells were also shown to be crucial during the development and progression of cancer. It was shown that LGR5+
crypt stem cells are the cells-of-origin in intestinal cancer and that CSCs in human colorectal cancer can be identified and isolated based on LGR5 expression.