Importantly, our findings predict differential sensitivity of these RNF43 mutational classes to treatment with PORCN inhibitors, Wnt antagonists that are currently evaluated for clinical treatment of RNF43‐mutant cancer patients (Janku et al, 2015; Zhan et al, 2017; Rodon et al, 2018; Zhang & Lum, 2018). Here, PORCN is linked to cancer.