Pancreatic stellate cells and pancreatic carcinoma: an unholy alliance.

The importance of the stromal compartment in the development, proliferation, invasion, metastasis and resistance of epithelial cancers has increasingly been recognized in recent decades [1, 2]. This stromal reaction is found in many carcinomas, e.g. in breast, prostate, colon, ovarian and pancreatic cancer. It is made up of stromal cells, endothelial cells, immune cells and extracellular matrix proteins. Moreover, the ECM proteins in the stroma act as a reservoir for growth factors released either by tumor or stromal cells, thus enabling autocrine and paracrine stimulation of the cells within the tumor mass. In this respect, groundbreaking work in solid tumors was done by Mina Bissell with breast carcinoma as her model system [3]. Recently, Vonlaufen