Why cancer stem cells can not be eradicated

Two main hypothesis have been put forward to explain cancer origin: according to the traditional view all cells are tumorigenic and can sustain tumor growth, while according to the hierarchical model this is only possible for a small population of cancer stem cells.

In a paper just published in Nature Scientific Report, an international team lead by Caterina La Porta from CC&B including researchers from Cornell University and the Weizmann Institute of Science demonstrate that all cancer cells can switch into cancer stem cells by activating a complex network of micro-RNAs, small non-coding RNA molecules regulating a vast number of stem cell factors. This transformation does not occur randomly, but only when the number of cancer stem cells goes below a critical threshold, thus providing a mechanism to maintain a constant cancer stem cell fraction inside the tumor. This discovery has profound implications for therapeutic strategies but also for our understanding of stem cells. Eliminating cancer stem cells from the tumor would become impossible because their disappearance would trigger the switch of other cancer cells.

Overshoot during phenotypic switching of cancer cell populations