In the case of the PTPRK‐RSPO3 translocation, recent studies in patient‐derived xenografts (PDXs) carrying the fusion transcript demonstrated that inhibition of WNT ligand secretion by porcupine blockade, or direct targeting of RSPO3 by antibodies, markedly inhibits tumor growth, promoting loss of cancer stem cell functions and differentiation (Chartier et al, 2016; Madan et al, 2016; Storm et al, 2016). Here, RSPO3 is linked to cancer.