Table 1.
Brief summary of the main carcinogenesis models reported in the literature of cancer: clonal evolution (stochastic) versus the stem cell models.
| STOCHASTIC | CANCER STEM CELL | |
|---|---|---|
| Origin of the neoplastic process | Any cell type (including a stem cell) | The cancer stem cell (a mutated stem cell) |
| Maintenance of the neoplasia | Any cell type that proves to be resistant to the presenting selection pressures | The cancer stem cell |
| The existence of neoplastic cells with stem cell features | It is just another phenotypic subtype of cancer cell (frequently associated with heterogeneous tumors), and possibly bearing a greater potential to promote resistance | The cancer stem cell (a “stable” subtype of cell) |
| Supporting evidence | The existence of cancer stem cells has not been demonstrated in all malignancies | It is “easier” to obtain a neoplasia from a mutated stem cell than from a normal well-differentiated cell. Most neoplasms have cells with stem cell phenotypic features |