YAP1 and cancer: Besides cancer-related proteins, YAP/TAZ-TEAD targets also include negative pathway regulators and ligands mediating the activity of other pathways [Sonic Hedgehog (SHH), Wnt/β-catenin, transforming-growth factor β (TGF-β) and NOTCH], thus indicating the existence of both autoregulatory feedback loops and crosstalk with stem-cell pathways [28–31].