FAM3B, also known as Pancreatic-derived factor (PANDER), is an islet-specific secreted cytokine specifically expressed at high levels in the islets of Langerhans of the endocrine pancreas. FAM3B can induce apoptosis of alpha and beta cells in a dose- and time-dependent manner. Previous studies showed that FAM3B regulates glucose and lipid metabolism through interaction with liver and endocrine pancreas. FAM3B silencing activates both extrinsic and intrinsic apoptotic pathways. In general, silencing FAM3B promoted p53 phosphorylation and induced p53 accumulation by decreasing Mdm2 expression, which resulted in apoptotic cell death.