News Life Running a cancer roadblock Research details how breast tumors thwart a protective piece of RNA By Tina Hesman Saey February 3, 2011 at 4:53 pm - More than 2 years ago Share this:Share Share via email (Opens in new window) Email Click to share on Facebook (Opens in new window) Facebook Click to share on Reddit (Opens in new window) Reddit Click to share on X (Opens in new window) X Click to print (Opens in new window) Print A small piece of RNA forms a big roadblock for breast cancer cells trying to spread away from the original tumor. This scrap of genetic material, a microRNA dubbed miR-335, stops tumor cells from making key proteins that allow the cells to move around the body.