Protein FAM3B,a cytokine-like protein identified in 2002,is also known as cytokine-like protein 2-21, pancreatic-derived factor (PANDER), C21orf11 and C21orf76,which is highly expressed in the pancreas and also found in the colon, kidney, prostate, small intestine and testis. There are 2 N-termini have been observed in the mature protein: the first at Glu-30, resulting from signal peptide cleavage, the second at Ser-46. 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.