The function of polycystins has mainly been explored in the context of PKD where mutations in the polycystins PC1 and PC2 give rise to a complex cell phenotype, characterized by increased cell proliferation and apoptosis, de‐differentiation, disturbed planar cell polarity, extracellular matrix alterations and abnormal fluid secretion.27 In cancer, however, the function of polycystins is unknown. This evidence concerns the gene PKD1 and cancer.