Researchers at Washington University School of Medicine in St. Louis have discovered why breast cancer patients with dense breasts are more likely than others to develop aggressive tumors that spread. The finding opens the door to drug treatments that prevent metastasis.
It has long been known that women with denser breasts are at higher risk for breast cancer. This greater density is caused by an excess of a structural protein called collagen.
Collagen fiber alignment at the tumor boundary (dashed lines) is predictive of prognosis. Fibers that tend to be perpendicular to the tumor surface (top right, for example) encourage metastasis and indicate a poor prognosis. Fibers that run parallel to the tumor surface (bottom right) protect against cancer spreading. Tumors without DDR2 or SNAIL1 tend to show the protective parallel fiber alignment.