What CSCs mean for cancer treatment
If cancer stem cells are the primary driver of cancer growth and metastasis, then effective cancer treatments must attack the CSCs. Shrinking a cancerous tumor or reducing the glut of leukemic cells in the bloodstream may offer temporary relief, but will not offer a long-term cure if CSCs are not eliminated. What’s more, if only the CSCs are eliminated, the rest of the cancer cells in the body will be attacked by the immune system or die out naturally since cancer cells that are not stem cells by definition do not have the ability to reproduce.
The most effective cancer treatments, therefore, will be those that specifically target CSCs. Such treatments likely will have few side effects because they leave other kinds of cells untouched. Finding such treatments will require that we know as much as possible about the qualities and behavior of CSCs.
Understanding CSCs can also help us modify current treatments for maximum effect. Researchers at Stanford’s Ludwig Center for Cancer Stem Cell Research and Medicine, for instance, discovered the reason that stem cells, including cancer stem cells, are resistant to the ionizing radiation used in many cancer treatments. Understanding this resistance may in the future help researcher find compounds that undermine this process and make CSCs vulnerable to radiation damage.
Another example concerns immune therapies in which the body’s own immune system is trained to attack cancer cells, which in the past researchers had high hopes would be effective against skin cancer. The therapies failed in clinical trials, and Stanford researchers showed why: the targets that the immune system was trained to attacked belonged not to the CSCs, but to slightly different daughter cells. The immune therapies seemed effective at first as they attacked the daughter cells, but they left the skin cancer stem cells untouched and therefore it could not cure the cancer.