YAP1 and neoplasm: Hippo pathway activity is dependent on the function of the transcriptional co-activators, the Yes-associated protein (YAP) and its close paralog transcriptional coactivator with PDZ-binding motif, TAZ (also known as WWTR1), which are downstream targets of a core kinase cascade comprised of mammalian Ste20-like kinases MST1/2 and large tumour suppressor LATS1/215.