According to a study published this month by Cornell University in Science Translational Medicine, obese women have a higher risk of developing breast cancer due to changes that obesity causes in obese women’s cellular and molecular structure. These changes include variations in the consistency of the breast tissue that resemble tumoral tissue, thus promoting the development of the pathology.
These findings were discovered from studies run in mice and women where it was proven that an increase of the fat tissue increases the stiffness of the membrane naturally surrounding the fat cells in the breast — known as the extracellular matrix (ECM). This occurs because obese women have more myofibroblastic cells in their fat tissue. Myofibroblasts are wound healing cells responsible for the scarring process. By releasing compounds that promote the construction of a new extracellular matrix around the cells, it pulls the cells together and induces the so-called healing process. Higher levels of myofibroblasts in the breast causes stiffening of the ECM even in the absence of an injury. On top of this, according with Claudia Fischbach, associate professor of biomedical engineering and the paper’s senior author, tumors also include in their mass a high level of myofibroblasts when compared to healthy tissue. Therefore, this scenario creates the optimal conditions for the development of tumors.
Until now, studies only showed the biochemical changes that obesity might cause. This new study adds an extra segment to the equation — the biophysical changes that also influence tumor cells’ expression in the region. This is a medical advance since it suggests the need to start using ECMs as clinical biomarkers, and that there might be a need to use finer-scale imaging techniques in mammograms so that denser ECMs are more easily detected among fat cells.
In reconstructive or plastic surgery procedures, it is common to inject myofibroblasts from obese donors in order to accelerate the regeneration process of the tissue. “What our data suggests is that it is really important where these cells are being taken from,” said Fischbach. “If you use these cells from an obese patient, they are very different and you may actually be driving malignancies if you implant them.” As a result, the researchers suggest against the use of fat cells from obese women in breast cosmetic surgeries, since these cells can induce breast cancer.