[2] The Hippo signaling has emerged as a critical cancer signaling network and is altered in human cancers.[1] Although it is considered to be a promising therapeutic target for cancers, perturbation of the Hippo pathway remains challenging, owing to limited targets, such as YAP and TEADs.[3] MST1/2 is essential for YAP/TAZ activity, and loss of MST1/2 results in cell hyperproliferation and tumorigenesis.[4] However, mutations in MST1/2 kinases have not been commonly found in human cancers, and it is not yet known how MST1/2 activity is diminished in cancers. This evidence concerns the gene YAP1 and cancer.