THE ESSENTIAL
- A study looked at the proven link between breast cancer and diabetes.
- Breast cancer is the second most diagnosed malignancy after certain types of skin cancer.
Breast cancer and diabetes are two distinct diseases but linked by a particular biological mechanism, according to a study from the University of California at San Diego published in Nature Cell Biology which explains how breast cancer suppresses insulin production, which leads to diabetes and promotes tumor growth.
Higher blood sugar levels
“No disease is an island because no cell lives alone“, underlines the corresponding author of the study, Shizhen Emily Wang, professor of pathology at the medical school of the UC San Diego.
“In this study, we describe how breast cancer cells alter the function of pancreatic islets to cause them to produce less insulin than needed, resulting in higher blood sugar levels in breast cancer patients by compared to women without cancer.“
Extracellular vesicles
According to Wang, the culprits are extracellular vesicles (EVs) that transport DNA, RNA, proteins, fats and other materials between cells.
With his team, he found that cancer cells secrete microRNA-122 in the vesicles (the microARN form one of the main regulatory pathways of gene expression)
When the vesicles reach the pancreas, they can enter cells responsible for insulin production, and deliver microRNA-122, preventing maintenance of normal blood glucose levels.
“Cancer cells use more glucose than healthy cells to fuel tumor growthexplains Wang. By increasing blood glucose which can be readily used by cancer cells, breast tumors make their own favorite food and in the process starve normal cells of this essential nutrient.“
Increased risk
Previous research had highlighted associations between the two diseases: women with diabetes, for example, have a 20 to 27% increased risk of developing breast cancer.
Insulin resistance – a key feature of diabetes – has been linked to breast cancer incidence and poor survival.
Population studies suggest that the risk of diabetes begins to increase two years after breast cancer diagnosis, and that ten years after diagnosis the risk is 20% higher in breast cancer survivors than in women who are not. patients of the same age.