A recent study suggests that obesity may alter the composition of breast adipose tissue and promote extracellular matrix stiffness, in turn increasing the tumorigenic potential of breast epithelial cells (Seo BR et al. Sci Transl Med. 2015;7[301]:301ra130).
A team led by investigators at Cornell University in Ithaca found that mammary fat from obese mice contained elevated numbers of myofibroblasts, which deposited denser and more rigid extracellular matrix. Putting the mice on a diet reduced the numbers of these cells.