Obesity Linked to Reduced Natural Protection Against Breast Cancer Growth: Study - Video

Obesity may increase breast cancer risk not only by promoting tumour growth, but also by reducing a natural defence that helps destroy cancer cells, according to new research from the University of Utah’s Huntsman Cancer Institute.

Published in Science, the study identified a fatty acid called 9S-HODE that appears to help trigger ferroptosis, a form of cell death that removes damaged or potentially cancerous cells.

Researchers found that fat cells in breast tissue produce different amounts of 9S-HODE depending on whether the surrounding tissue is lean or affected by obesity. In laboratory studies and breast tissue samples from donors, lean fat cells produced substantially more 9S-HODE than obese fat cells.

This difference may create different environments for cancer cells. With higher levels of 9S-HODE, cancer cells were more likely to undergo ferroptosis, potentially limiting their ability to survive and grow. In contrast, lower levels in obese tissue appeared to reduce this natural protective effect.

The researchers then tested their findings in mice. Increasing 9S-HODE levels in fat cells from obese animals suppressed breast tumour growth, suggesting that restoring the molecule could potentially become a future treatment strategy.

The discovery offers a different way of understanding the relationship between obesity and cancer. Instead of obesity only adding factors that encourage cancer, the researchers suggest it may also remove substances that normally protect tissues from cancer development.

However, the findings are still at an early stage. The experiments were conducted in preclinical models and laboratory tissue, so it is not known whether increasing 9S-HODE would safely or effectively slow breast cancer in people.

Researchers also stressed that obesity is only one of several factors linked to breast cancer. Further research, including human studies, will be needed before any clinical treatment based on 9S-HODE can be considered.

REFERENCE: Curtin, M. C., et al. (2026). Lean adipocyte oxylipin signaling restrains breast cancer through ferroptosis. Science. DOI: 10.1126/science.aea4287.