Periostin, a multifunctional matricellular protein in inflammatory and tumor microenvironments

• Functions of periostin in inflammatory diseases
• Functions of periostin in tumor progression
• The sources of periostin in inflammatory diseases and tumors
• Model of roles of periostin in inflammatory and tumor microenvironments

The behavior and fate of cells in tissues largely rely upon their cross-talk with the tissue microenvironment including neighboring cells, the extracellular matrix (ECM), and soluble cues from the local and systemic environments. Dysregulation of tissue microenvironment can drive various inflammatory diseases and tumors. The ECM is a crucial component of tissue microenvironment. ECM proteins can not only modulate tissue microenvironment but also regulate the behavior of surrounding cells and the homeostasis of tissues. As a nonstructural ECM protein, periostin is generally present at low levels in most adult tissues; however, periostin is often highly expressed at sites of injury or inflammation and in tumors within adult organisms. Current evidence demonstrates that periostin actively contributes to tissue injury, inflammation, fibrosis and tumor progression. Here, we summarize the roles of periostin in inflammatory and tumor microenvironments.