View Full Version : Stem Cell Question....treatment question

05-27-2006, 05:28 PM
In my reading I understand that Max Wicha, MD, director of the University of Michigan Comprehensive Cancer Center in Ann Arbor was part of a team that discovered the presence of stem cells in human breast tumors. Back a few years and more recently he has said:

"The goal of all our existing therapies has been to kill as many cells within the tumor as possible," Wicha says. "This study suggests that the current model may not be getting us anywhere, because we have been targeting the wrong cells with the wrong treatments. Instead, we need to develop drugs targeted at the tumor's stem cells. If we are to have any real cures in advanced breast cancer, it will be absolutely necessary to eliminate these cells.
"What this means for women with cancer is that, for the first time, we can define what we believe are the important cells - the cells which determine whether the cancer will come back or be cured," Wicha adds. "Before this, we didn't even know there were such cells."

"Most current cancer therapies, particularly chemotherapy, seem to kill the more differentialed cells in a tumor while sparing the cancer stme cells that can then repopulate and grow. Cancer stem cells contain "transporter" proteins that literally pump out chemotherapy drugs before the drugs can kills them This may explain why many treatments cause cancer to shrink down but don't necessarily make patients live longer. If we're killing the wrong cells in the cancer, all we're doing is reducing the number od non-stem cells The root of the cancer is left behind and causes recurrence." Another problem is that many therapies are directed to cancer cells that proliferate rapidly. However, cancer stem cells proliferate much more slowly than differentiated cancer cells, which renders traditional chemo's less effective."

One approach to killing cancer stem cells is to target the pathways (biochem. networs) that regulate their replication....3 key ones identified..Hedgehog, Notch and Wnt. According to Dr. Wicha, drugs that inhibit these pathways have a more toxic effect on cancer stem cells than on normal stem cells. He expects inhibitors of these pathways to begin within the next year or two.

NOW....to what I am very curious about specifically.....

Dr. Wicha speculates that a womans risk of breast cancer may be related to the number of stem cells in her breast and that tamoxifen may reduce stem cell populations, which would explain why it helps prevent recurrence of breast cancer.

My question is: Is there any reason to think that with ER+ (or perhaps negative breast cancer) tamoxifen might be a useful addition to the AI's we currently use? Has this ever been considered? Perhaps its a silly question but I can't help but wonder if even a modestly positive impact might be useful.


05-27-2006, 07:15 PM
They did do a trial using tamoxifen vs Arimidex vs Arimidex and tamoxifen together. The dual combination was (oddly) worse than taking either drug on it's own. The outcome was profound and with a lot of side effects.


05-27-2006, 08:00 PM

Thanks for responding to what I now realize is a silly question....although your information is interesting and makes me wonder.......but the more I read the more I realize I totally missed the boat in this stem cell business....this has to do with PTEN. I really have to take the time and find a way to update myself on this research.