Women with dense breasts are at a higher risk of breast cancer due to the presence of collagen in excess. Collagen is a structural protein.
"We have shown how increased collagen in the breasts could increase the chances of breast tumors spreading and becoming more invasive," said Gregory D Longmore, MD, professor of medicine. "It doesn't explain why women with dense breasts get cancer in the first place. But once they do, the pathway that we describe is relevant in causing their cancers to be more aggressive and more likely to spread," he stated.
During experiments on mouse models of breast cancer, researchers found that a protein that sits on the surface of tumor cells, called DDR2, attaches itself to collagen and this can cause the spread of tumor cells.
"We had no idea DDR2 would do this. The functions of DDR2 are not well understood, and it has not been implicated in cancer — and certainly not in breast cancer — until now," said Longmore.