DNMT1 and pancreatic neuroendocrine tumor: Immunofluorescence (IF) and western blot assays were used to identify increased DNMT1 protein levels in MEN1-parathyroid tumors (Figure 3A and 3D), mouse pancreatic endocrine tumors from Men1 KO mice (Figure 3B and 3E), and mouse parathyroid tumors from a different Men1 KO mouse model (Figure 3C).