A surgeon can excise breast cancer from the body, but even the most skilled scalpel may not be able to remove every cell — especially when the cells have spread from the original disease site elsewhere in the body. This proliferation and migration of breast cancer cells involves many still unknown molecular means, but researchers at Hiroshima University have elucidated at least one mechanism, involving protein receptors that bind to one another. With the discovery, they may have also uncovered how short chains of protein building blocks could serve as a novel anticancer drug.