Active Roles of Tumor Stroma in Breast Cancer Metastasis

Figure 1

Schematic presentation of breast cancer progression accompanied with stromal cells. Normal breast duct is composed of a layer of epithelial cells and a layer of myoepithelial cells separated from the stroma by a basement membrane. Stromal cells include fibroblasts, BMDCs, endothelial cells, and other cells. Ductal carcinoma in situ (DCIS) is associated with luminal epithelial cells proliferation, and recruitment and expansion of stromal cells. In invasive ductal carcinoma, the myoepithelial cell layer is degraded with the underlying basement membrane and cancerous cells invade the surrounding microenvironment. Advanced breast cancer is associated with complete loss of myoepithelial cell layer and basement membrane, invasion of epithelial cells, proliferation of stromal cells, and angiogenesis.