YAP1 and cancer: To investigate additional pathways that agrin treatment might impact upon in the context of epicardial EMT, we examined Hippo-YAP signaling, previously shown to be essential for the development of the epicardium and epicardial cell differentiation (Xiao et al., 2018) and to act as a potent inducer of EMT in other cell types, most notably cancer (Cheng et al., 2020).