RSPO2 and colorectal neoplasm: Colorectal tumors with mutated RNF43/ZNRF3 or R-spondins 2/3 are sensitive to abrogation of Wnt secretion (Degirmenci et al., 2018a, 2018b; Koo et al., 2012; Madan et al., 2016; Storm et al., 2016).