MST1 and neoplasm: It is important to note that, although Yap is clearly the oncogene that is negatively regulated downstream of Mst1/2 in liver, Yap also has antiproliferative, propapototic outputs in other cellular milieus, presumably reflecting its context-dependent interactions with transcriptional regulators unrelated to those that define Yap function in the Hippo tumour suppressor pathway (e.g., p73; Matallanas et al, 2007; Oh and Irvine, 2010).