Active Roles of Tumor Stroma in Breast Cancer Metastasis

Figure 2

Stromal cells involved in metastatic cascade. (1) Myofibroblasts, fibroblasts, and macrophages and other BMDCs play a major role in promoting primary tumor growth. (2) Intravasation is enhanced by the paracrine interactions between tumor cells and macrophages. (3) The fusion of tumor cells and macrophages is questionable (?) and may promote the survival of the tumor cells in vasculature. (4) During extravasation, direct interaction of tumor cells and macrophages enhance tumor cell egress of the vessels. (5) BMDCs and myofibroblasts stimulate tumor cell metastatic dissemination. (6) The recruitment of endothelial cells, myofibroblasts, and BMDCs to the tumor site increases vascularization.