Do cancer stem cells exist? Developing therapies for debatable targets.

Currently, over sixty clinical trials in targeting cancer stem cells in some form or another are underway. Cancer stem cells are believed by some to be treatment-resistant cancer cells with the capability of self-renewal to form normal as well as new cancer cells. Thus, despite seemingly effective treatment to eradicate tumors, the cancer stem cell theory supposes that these cells may remain, proliferate and cause a relapse in tumor formation that is seen in many forms of cancers. The concept of the cancer stem cell is not fully accepted by all in the field, and such opponents suggest further evidence is needed to confirm their existence.

At any rate, based on the cancer stem cell theory, even cancer stem cell-specific treatments may prove too slow in their effect causing a gradual rather than rapid regression of disease. A combination therapy of traditional treatment approaches and cancer stem cell-specific treatments would likely have the most effective outcome in leading to tumor eradication based on the cancer stem cell theory (Figure 1).

 

Figure 1. Outcomes based on traditional, cancer stem cell-specific, and combined therapies. Adapted from Kaiser, Science 347(6219):226-229, 2015.

As so much money and effort is being put into the cancer stem cell idea and approach to treatment, what do you think about this theory and any particular promise it holds for advancing cancer treatment and prognosis?

Kaiser (2015) The cancer stem cell gamble. Science 347(6219):226-229.