YAP1 and neoplasm: Interestingly, this moderate tumor mass reduction coincided with a strong downregulation of an expanded-lacZ (ex::lacZ) reporter (Boedigheimer and Laughon, 1993; Hamaratoglu et al., 2005), indicating deregulation of the Hippo (Hpo) pathway and reduced Yorki (Yki) activity in the absence of Ftz-F1 (Fig. 3G).