Advances in pancreatic cancer stem cells, tumor- associated macrophages, and their interplay

Cancer stem cells are currently considered to contribute to the aggressiveness and therapeutic resistance of pancreatic cancer, providing new hope for the cure of this disease and resulting in a growing body of mechanistic research. Solid tumors are heterogeneous cellular entities that contain malignant cells and a surrounding nonmalignant stroma. An abundant tumor stroma with a high density of tumor-associated macrophages is a distinguishing characteristic of pancreatic cancer. Accumulating evidence has indicated that tumor-associated macrophages can promote pancreatic cancer progression by inducing angiogenesis, invasion, metastasis, and immune suppression. However, there is limited information about the interactions between tumor-associated macrophages and pancreatic cancer stem cells. In this article, we review the current understanding of the biology of pancreatic cancer stem cells and tumor-associated macrophages and their molecular interplay.