LGR5 and colorectal carcinoma: CRC models provide a unique opportunity to clarify the role of CSCs and non-CSCs in the metastatic process, because hierarchical organization is maintained during disease progression and functional CSCs are marked by Lgr5 expression (Cortina et al., 2017, de Sousa e Melo et al., 2017, Schepers et al., 2012, Shimokawa et al., 2017).