CD274 and cancer: In addition, similarly to what is seen in PD-L1 expressing cancer cells, lymphatic endothelial cells and MHC-II expressing melanoma, intracellular PD-L1 and MHC-II signaling might inhibit apoptosis in cardiac endothelial cells and cardiomyocytes via MAPK/Erk and PI3K/Akt pathways (Azuma et al., 2008; Hemon et al., 2011; Gato-Cañas et al., 2017).