Public release date: 11-Jan-2008

Scientists at the Johns Hopkins Kimmel Cancer Center say they have evidence that cancer stem cells for multiple myeloma share many properties with normal stem cells and have multiple ways of resisting chemotherapy and other treatments.

A report on the evidence, published in the Jan. 1 issue of the journal Cancer Research, may explain why the disease is so persistent, the Johns Hopkins scientists say, and pave the way for treatments that overcome the cells’ drug resistance. Multiple myeloma affects bone marrow and bone tissue.

“Cancer stem cells that have distinct biology and drug sensitivity as compared with the bulk of a cancer may explain why multiple myeloma, like many other cancers, so often relapses even after chemotherapy puts patients into remission,” says Richard J. Jones, M.D., professor and director of bone marrow transplant at Hopkins’ Kimmel Cancer Center and one of the scientists who authored the new report.

To their surprise, the research team noted that the multiple myeloma stem cells resemble other types of adult stem cells and exhibit similar properties that may make them resistant to chemotherapy. They found that the stem cells contain high levels of enzymes that neutralize toxins, like cancer drugs, and expel them through miniature pumps on their cell surface. The investigators believe that these drug-fighting enzymes and pumps – also plentiful in normal stem cells – may help cancer stem cells resist treatment.

“Nature made normal stem cells very hearty for a reason, namely to survive and help repair damaged tissues and organs after injury or illness,” says William Matsui, M.D., an assistant professor of oncology at Hopkins and the study’s lead investigator. “To us, it makes sense that the same processes that protect normal stem cells also exist in cancer stem cells to make them resistant to chemotherapy. We need to develop new ways to target the specific biology of cancer stem cells to prevent the continued production of mature tumor cells and disease relapse.”

“Standard cancer therapy is like mowing the weed – it gets rid of the disease transiently but the dandelion always grows back. We need to get rid of the root to cure disease, and therefore need a different type of therapy – mowing won’t work,” says Jones.

Ralph’s Note- When Stem Cells become the disease not the cure. Good science on this double edge sword.