CD274 and pancreatic neuroendocrine tumor: Notably, in pancreatic (RT2-PNET, pancreatic neuroendocrine tumors), breast (PyMT, polyoma middle T oncoprotein) and brain (GBM, glioblastoma) tumor mouse models, expression of PD-L1, the ligand of PD-1, was enhanced by interferon-γ-expressing T cells in tumors relapsed from VEGF-A inhibition [9].