LGR5 and glioblastoma: For example, glioblastoma (GBM) CSCs frequently express neural lineage markers such as Nestin and SOX2,3,4 whereas gastrointestinal cancers may harbor CSCs characterized by leucine-rich repeat-containing G-protein-coupled receptor 5 (LGR5) or CD166 expression.5 This heterogeneity suggests that CSC identity is shaped by both intrinsic genetic programs and extrinsic cues.