Figures & data
Figure 1. CSCs can originate by different mechanisms. CSCs can theoretically emerge by mutations on embryonic stem cell populations and therefore lead to the formation of embryonic tumors (a). In addition, the embryonal rest theory speculated that undifferentiated remnants of developmental processes could contribute to tumor initiation. The prevailing theories for adult tumor formation speculate that accumulation of mutations might lead to the dynamic reversion of a differentiated phenotype into a malignant stem cell-like state (b). Alternatively, the similarities between CSCs and adult stem cell populations bring about the possibility that mutations directly affecting tissues-specific progenitor cells underlie CSC generation (c). Nowadays, it is hardly believed that a single hypotheses bears true for all different tumor types. Instead, different mechanisms might underlie the appearance of CSCs in a tumor, or even patient, specific manner.
