Fig. 2.

Schematic representation of the cancer stem cell microenvironment or niche. Progression of tumor needs a cooperative interplay between CSCs and their niche. The CSC niche made of various cells including mesenchymal stem cells (MSCs), endothelial cells, cancer-associated fibroblasts (CAFs) and immune cells, tumor-associated macrophages (TAMs), regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), T cells and B cells. These cells secrete various growth factors and cytokines which promote tumorigenesis, tumor progression, and immunosuppression