A new study has found that linoleic acid, a common fat found in seed oils like soybean and safflower oil, can increase the growth of a dangerous type of breast cancer known as triple-negative breast cancer.
This type of cancer is hard to treat because it lacks three key hormone receptors that other breast cancers have.
The study, done by researchers at Weill Cornell Medicine, may help doctors create new diet plans or treatments for people with this cancer.
The researchers discovered that linoleic acid activates a cancer growth pathway called mTORC1. This happens when linoleic acid binds to a protein in the cancer cells called FABP5. This protein is found in high amounts in triple-negative breast cancer cells.
When the researchers compared different types of breast cancer, they found that this growth effect only occurred in the triple-negative subtype, not in hormone-sensitive types.
In experiments with mice that had triple-negative breast cancer, a diet high in linoleic acid caused tumors to grow faster. The mice also had more FABP5 protein and more active mTORC1 in their cancer cells.
The researchers then looked at blood and tumor samples from human patients who were newly diagnosed with this type of cancer and found higher levels of FABP5 and linoleic acid there too.
Dr. John Blenis, senior author of the study, explained that this research helps show how certain fats in our diet may affect cancer risk and growth. Linoleic acid is an omega-6 fatty acid that the body needs in small amounts.
However, modern diets, especially in Western countries, have much more of this fat than needed because of its use in cooking oils and processed foods.
Past studies gave mixed results on whether omega-6 fats like linoleic acid were harmful. This new study is the first to show a clear biological link between linoleic acid and cancer growth in a specific type of breast cancer.
The scientists believe that the protein FABP5 is the key to this effect. When linoleic acid binds with FABP5, it triggers the mTORC1 pathway, which controls how cancer cells grow and use energy.
The study suggests that FABP5 could be used as a marker to identify patients who might benefit from dietary changes or special treatments. Right now, there are no targeted drugs for triple-negative breast cancer, so this discovery may offer new hope for developing better therapies.
The team also began looking into whether the same linoleic acid and FABP5 process affects other cancers. In early tests, they saw similar effects in some prostate cancers. They believe this process might also play a role in other diseases, including obesity and diabetes, where cell metabolism is out of balance.
Dr. Nikos Koundouros, first author of the study, said this may be just the beginning. If the pathway is important in more diseases, blocking FABP5 or controlling linoleic acid intake might help in many ways.
If you care about breast cancer, please read studies about how eating patterns help ward off breast cancer, and soy and plant compounds may prevent breast cancer recurrence.
For more health information, please see recent studies about how your grocery list can help guard against caner, and a simple way to fight aging and cancer.
The study is published in Science.
