LGR5 and cancer: Studies have confirmed that the tumorigenic subpopulation of mouse leucine-rich repeat-containing G-protein coupled receptor 5 (LGR5)-positive cells exists in a slow-cycling state and a unique 22-gene signature that characterizes these slow-cycling CSC-like cells, which often contributes to cancer chemoresistance, has been identified (Shiokawa et al., 2020).