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![Drug and apoptosis resistance in cancer stem cells: a puzzle with many pieces](https://image.oaes.cc/648c863b-2049-4fab-90a7-d181acba4b5b/4906.fig.2.jpg)
Figure 2. CSCs role in tumor development and progression. CSCs are originated from the NSCs through the tumorigenic transformation of several potential pathways including Hg, epithelial-to-mesenchymal transition (EMT), and the reverse process mesenchymal-to-epithelial transition (MET). CSCs and drug-induced CSCs (Di-CSCs) can be enriched following conventional chemotherapy treatment. CSC: Cancer stem cell; NSCs: normal stem cells.