YAP1 and cancer: The Hippo pathway functions as a central regulator of tissue homeostasis, coordinating a conserved kinase cascade from the tumor suppressors MST1/2 to the oncoproteins YAP/TAZ to balance cell proliferation and apoptosis.311 While Hippo pathway dysregulation induces YAP/TAZ-driven overexpression of prosurvival genes (e.g., c-MYC and survivin) and tumorigenesis in model organisms,312,313 human cancers rarely exhibit Hippo gene mutations, suggesting that the oncogenic role of the Hippo pathway is predominantly driven by microenvironmental dysregulation.