Why obesity ups breast cancer risk

Obesity results in stiffer breast tissue that promotes the growth of cancer, a new study says. Obesity leads to a stiffening of the meshwork material that surrounds fat cells in the breast, called the extracellular matrix, and these biomechanical changes creates the right conditions for tumours, the findings showed.

Women who are obese have a higher risk and a worse prognosis for breast cancer, but the reasons have remained unclear till now. "We all know that obesity is bad; the metabolism changes and hormones change, so when looking for links to breast cancer, researchers almost exclusively have focused on the biochemical changes happening,” said study senior author Claudia Fischbach, associate professor of biomedical engineering at Cornell University in New York.

"But what these findings show is that there are also biophysical changes that are important," Fischbach noted. The findings could lead to recognition of stiffer breast cells as a clinical biomarker for breast cancer. Also, the results should caution doctors against using certain fat cells from obese women in plastic and reconstructive breast surgeries, as these cells can promote recurring breast cancer.

The findings, published in the journal ‘Science Translational Medicine’, suggest clinicians may need to employ finer-scale imaging techniques in mammograms, especially for obese women, to detect denser fat cells in the breast.