YAP1 and cancer: Recently, Sivaraj et al. reported that YAP1/TAZ, a key component of the Hippo pathway, is a negative regulator of bone angiogenesis, which could coimmunoprecipitate with HIF-1α under hypoxic conditions and repress the transcription of its downstream genes.18 The role of metformin in regulating the Hippo pathway in the field of cancer has been extensively studied; however, whether it can modulate YAP1/TAZ signaling in endothelial cells has not been reported.