A tiny protein called RhoC found in breast tumors may someday give doctors and patients an early warning system that could spot dangerously aggressive breast cancer long before it begins to spread, and identify the need for aggressive treatment. A test to detect the protein is still more than a year away from clinical trials. But promising early results show that RhoC can serve as a marker for breast tumors.
RhoC, whose full name is RhoC-GTPase, is an enzyme involved in changing the internal skeleton of a cell - changes that allow a cell to polarize or move. That ability is important in muscle cells, which produce a lot of RhoC. But in cancerous non-muscle cells, RhoC is key to the structural changes that give a cell the ability to break off from a tumor, float through the body in the bloodstream, and take hold in a satellite location - in other words, to metastasize.
Researchers developed the test based on their research on the RhoC gene, and proved its effectiveness in 182 tissue samples. "This is a very promising marker for small but invasive breast cancers that may metastasize, which right now are hard to identify," says lead author Celina Kleer, M.D., an assistant professor of pathology at the U-M Medical School who specializes in breast cancer. "While more research is needed before clinical testing can begin, we hope it will help identify early-stage cancer that could be vulnerable to aggressive treatment, perhaps with drugs that target Rho protein."