Upstream regulation of Hippo signalling via MST kinases has been shown to be dispensable in the pituitary, however, inactivating mutation of the kinase LATS1, which directly inhibits the effectors, results in tumour formation, where these aggressive tumours are comprised of proliferating, YAP/TAZ-accumulating, SOX2+ cells [52]. This evidence concerns the gene WWTR1 and neoplasm.