RSPO1 and cancer: Nearly all CRCs harbor activating mutations in the Wnt pathway or fusion of RSPO(R-spondin-1) genes, allowing for the expansion of cancer cells without Wnts and R-spondins, while normal epithelial cells arrest (Nusse 2017;Sato et al. 2011;Seshagiri et al. 2012;van de Wetering et al. 2015).