The key to a cure for breast cancer may lie in turning off breast cancer’s stem cells, according to a discussion Wednesday at the World Stem Cell Summit in Detroit.
The University of Michigan’s Max Wicha said breast cancer stem cells are much more resistant to treatment with radiation and chemotherapy.
And they alone — unlike normal tumor cells, which Wicha called “dead ends” — are capable of spreading to the liver and the lung, the metastasis that kills so many breast cancer patients.
Wicha, professor of internal medicine at UM and director fo the UM Comprehensive Cancer Center, said modern medicine has gotten very good at shrinking tumors, but that isn’t what really kills cancer.
“If the stem cells are left intact it’s like leaving the root of a plant, it just regrows,” he said. “We think we’ve used the wrong models to develop a lot of our therapeutic agents. We’ve developed a lot of agents that are good at shrinking tumors, but patients aren’t necessarily living any longer.”
What’s worse, when radiation or chemotherapy is given, dying cancer cells give off a distress signal, an inflammatory hormone, that both protects the stem cells from death and trigger them to regnerate the tumor.
In 2006, researchers at UM began the first clinical trial targeting breast cancer stem cells. The phase I/II trial is in collaboration with researchers at Baylor College of Medicine in Houston and Dana Farber Cancer Institute in Boston.
The breast cancer trial involves a drug that was shown in the lab to target cancer stem cells. The drug is combined with the common chemotherapy drug docetaxel. The ultimate goal is to shrink both the stem cells and the non-stem cells that make up the bulk of the tumor. Researchers believe targeting both cell populations is key to killing the cancer.
Wicha is also involved with a company, Oncomed Pharmaceuticals, that is doing breast cancer stem cell studies at the Karmanos Cancer Center in Detroit.
Wicha said that the number of normal breast stem cells in a woman’s breast is a risk factor for breast cancer. And he said nutrition in childhood and adolescence may be a key in limiting that risk.
UM researchers were the first to identify cancer stem cells in solid tumors, finding them in breast cancer tissue. Results of this work were first published in 2003. Later, UM researchers were first to identify cancer stem cells in pancreatic cancer and in head and neck cancer. Stem cells have now been identified in most cancer types.
Also speaking in the session Wednesday were Ram Mandalam, CEO of Cellerant Therapeutics Inc. of San Carlos, Calif., and breast cancer patient advocate Jane Perlmutter.
Mandalam said his company is focused on using stem and progenitor cells as a temporary treatment when the body’s blood-forming cells turn off — helping people survive aggressive chemotherapy or radiation exposure.
And Perlmutter, a 25-year breast cancer survivor, told the group that today’s patient advocacy must concentrate on areas that question the status quo, because too many women are still dying.
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