This Omega-6 Fatty Acid May Help TNBC Tumors Thrive

Omega-6 fatty acids — found in vegetable oils, seeds, nuts, and meats — help support your brain, bones, and metabolism. But new research in animals suggests that aggressive cancer cells may be using a specific omega-6 fatty acid to survive treatment.   

Triple-negative breast cancer is notoriously difficult to treat and is more likely to come back (recur) than other breast cancers. So scientists are trying to figure out how some breast cancer cells come back in order to develop better treatments.

The study focused on how triple-negative breast cancer cells use arachidonic acid to possibly evade treatment and the body’s natural immune responses. Arachidonic acid is an omega-6 fatty acid commonly found in the fatty parts of red meat and fish. 

Researchers at Baylor College of Medicine gave mice with triple-negative breast cancer a combined treatment of paclitaxel (Taxol) and pembrolizumab (Keytruda) over an 18-day period. The treatment got rid of the tumors in about half the mice. 

Tumors came back in 20% of the mice and didn’t go away when the animals received the same combined treatment. The cancer cells that came back and were resistant to treatment had high contents of omega-6 fatty acids. 

The researchers found that the cancer cells also sent these fatty acids to nearby white blood cells that normally help the body fight tumors. The fatty acids reprogrammed these immune cells so that instead of fighting the tumors, they released compounds that helped them grow. 

The researchers next gave the mice with treatment-resistant tumors a diet that didn’t include omega-6 fatty acids for 15 days. During this time the animals were also treated with paclitaxel and pembrolizumab. With the change in diet, the tumors in the animals began to shrink.

The results suggest that fatty acids serve as an energy source for the tumors and can help cancer cells “fight against our immune system,” Xiang Zhang, PhD said in a statement. Zhang was the lead author of the study and is the director of the Lester and Sue Smith Breast Cancer Center at Baylor.

Because this study looked at mice with triple-negative breast cancer, it’s too soon to tell if similar results would be seen in people consuming a lot of omega-6 fatty acids. However, people with TNBC may want to consider changing their diet so that it’s lower in omega-6 fatty acids, “which is not significantly different from the general advice to lower red meat, fat, and sodium intake,” Zhang said.