Fig. 1

The connection between EMT and CSCs. CSCs can be generated by cancer cells that undergo a partial EMT process. Compared with cancer cells, CSCs are more invasive and drug-resistant and have great ability of tumor-initiation. CSCs are prone to intravasate into adjacent blood vessels. After entering the circulation, the metastatic CSCs will undergo transendothelial migration to extravasate into a new secondary site. Subsequently, CSCs can be transformed into cancer cells again via the MET process