CD44 and colorectal cancer: Several studies have shown that CSC-related factors, including aldehyde dehydrogenase 1 (ALDH1) and leucine-rich repeat containing G protein-coupled receptor 5 (LGR5), are associated with colorectal cancer progression.[49–51] As for the prognostic value of these markers, Horst et al[45] implied that CD133 might be of the most clinical relevance, while the combined evaluation of CD133, CD44, and CD166 might even be more valuable to separate high-risk groups from low-risk colorectal cancer cases.