Scientists at Stanford University School of Medicine have discovered stem cells that trigger the development of melanoma skin cancer in people. They took samples of melanoma from patients at the Stanford Cancer Center and studied the proteins on the surface of the cells. They found that up to 41percent of the cells had a protein on them called CD271. They then put some of the melanoma into mice, some of which had the CD271 protein and some of which didn’t. The cells with the protein were much more likely to grow into tumors than the ones that didn’t have the protein, suggesting that CD271 has stem cell like properties. The stem cells could produce bulk tumor cells as well as new stem cells, which is a classic way in which stem cells behave and one of the reasons why caution should be used when developing stem cell therapies for people.
The stem cells also lacked other types of proteins that the immune system would attack and destroy, possibly explaining why some patients don’t respond to immuno therapies for cancer.
Lead researcher Dr Alexander Boiko revealed, "These cells lack the traditional melanoma cell surface markers targeted by these treatments. Without wiping out the cells at the root of the cancer, the treatment will fail.
"This could be the reason why we often see melanoma patients relapsing and coming back to the clinic. Our research indicates that it may be more appropriate to also target cells expressing CD271."
Dr. Kat Arney from Cancer Research UK said,
“"Researchers are finding cancer stem cells in many different types of tumor, and many scientists believe they are at the heart of a wide range of cancers.”
The researchers think that these cancer causing stem cells are ‘immortal’ and do not die like normal cells and keep on producing more cancer cells. They theorize that this may be why many patients relapse after they have had chemotherapy.
Source: Cancer Research UK, Press Release, 2nd July 2010.
Joanna is a freelance health writer for The Mother magazine and Suite 101 with a column on infertility, http://infertility.suite101.com/.