The Yes-associated protein (YAP) family of transcriptional co-activators are emerging as potent oncoproteins that strongly drive cell proliferation in many types of stem/progenitor cells and cancers (Harvey et al., 2013; Irvine and Harvey, 2015; Pan, 2010, 2015; Piccolo et al., 2013). The gene discussed is YAP1; the disease is cancer.