Figure 1.

Schematic representation of the modular structure of periostin showing its domain-specific binding sites for extracellular matrix proteins promoting fibrillogenesis and fibrogenesis, as well as cell surface signaling molecules, notably integrins, whose activation by their interaction with this matricellular glycoprotein regulate diverse cellular functions, including cell motility, survival and proliferation. Overexpression of periostin induced by fibrogenic factors that include transforming growth factor-β family members and angiotensin II in cancers such as intrahepatic cholangiocarcinoma and pancreatic ductal adenocarcinoma may be playing a key role in facilitating desmoplasia and creating a tumor-supportive microenvironment that promotes malignant cell invasion, metastatic colonization, and chemotherapeutic resistance. See text for specific details.