Both, APC and RNF43, are frequently mutated negative regulators of the Wnt/β‐catenin signaling pathway (Polakis, 2012; de Lau et al, 2014; Tsukiyama et al, 2015; Zhan et al, 2017)—a pathway that is aberrantly regulated in various cancers (Polakis, 2012; Giannakis et al, 2014; Zhan et al, 2017). Here, RNF43 is linked to cancer.