Tracing and targeting cancer stem cells: New venture for personalized molecular cancer therapy

Figure 3 Tracing and targeting cancer stem cells. A: The complex process of distant metastasis including invasion of the tumor microenvironment, EMT, shedding of CSCs into the blood stream (intravasation), MET and invasion of circulating CTCs to the other tissues (extravasation). Only circulating CSCs are able to survive in the circulating blood, escape from immune-surveillance and home to secondary organs; B: The list of known compilation CSC-related molecular markers for different solid tumors and hematopoietic malignancies. The level of specificity of these markers differs per each type of tumor. Markers are ordered alphabetically and not according to their sensitivity or specificity; C: Four important approaches of CSC-targeted therapy. CSC: Cancer stem cell; CC: Cancer cell; NC: Normal cell; EMT: Epithelial-mesenchymal transition; MET: Mesenchymal-epithelial transition; PI3K: Phosphoinositide 3-kinase; MAPK: Mitogen-activated protein kinase; TGF: Transforming growth factor; mTOR: Mechanistic target of rapamycin; RAS: Ras-activated signaling; PD-1: Programmed death 1; PD-L1: Programmed death-ligand 1; EpCAM: Epithelial cell adhesion molecule.