Avastin, Sutent increase breast cancer stem cells, study shows

“This study provides an explanation for the clinical trial results demonstrating that in women with breast cancer antiangiogenic agents such as Avastin delay the time to tumor recurrence but do not affect patient survival. If our results apply to the clinic, it suggests that in order to be effective, these agents will need to be combined with cancer stem cell inhibitors, an approach now being explored in the laboratory,” says study author Max S. Wicha, M.D., director of the U-M Comprehensive Cancer Center.

The researchers treated mice with breast cancer using Avastin (bevacizumab) and Sutent (sunitinib), both of which work by stopping the growth and formation of blood vessels, a process called angiogenesis. The researchers found that tumors treated with these drugs developed more cancer stem cells, the small number of cells within a tumor that fuel a cancer’s growth and spread and that are often resistant to standard treatment. Both the number of cancer stem cells and the percentage of cancer stem cells that make up the tumor increased after being treated with each of these therapies.