Pancreatic cancer stroma: controversies and current insights.

Pancreatic cancer is characterized by a dense stromal response. The stroma includes a heterogeneous mass of cells, including pancreatic stellate cells, fibroblasts, immune cells and nerve cells, as well as extracellular matrix proteins, cytokines and growth factors, which interact with the tumor cells. Previous research has indicated that stromal elements contribute to tumor growth and aggressiveness. However, recent studies suggest that some elements of the stroma may actually restrain the tumor. This review focuses on the complex interactions between the stromal microenvironment and tumor cells, discussing molecular mechanisms and potential future diagnostic and therapeutic approaches by targeting the stroma.