Results from a mouse study led by the Institute for Research in Biomedicine (IRB) Barcelona suggest that palmitic acid, a dietary fatty acid found in palm oil, plays a role in promoting cancer metastasis.

In a mouse model of human mouth and skin cancer, the team found that consumption of palmitic acid, but not oleic acid or linoleic acid, seemed to promote metastatic tumor growth.

Cancer metastasis, where cancer spreads to other areas of the body, remains the main cause of death from cancer and is hard to treat effectively.

Changes in fatty acid uptake and metabolism are common physiological markers of metastasis, “yet evidence of the underlying biology, as well as whether all dietary fatty acids are prometastatic, is lacking,” write the researchers in the Nature article describing their research.

To investigate further, Salvador Aznar Benitah, a senior researcher and group leader at IRB Barcelona, and team tested whether dietary palmitic, oleic or linoleic acid, could influence whether cancer would metastasize in a mouse model of oral cancer or melanoma.

They found that mice fed palmitic acid were more likely to undergo cancer metastasis than those fed oleic acid (omega-9) or linoleic acid (omega-6). Notably, they found this prometastatic effect seemed to have a long-lasting impact on the tumor DNA, as tumor cells from mice fed palmitic acid or cells exposed to palmitic acid in the lab continued to promote metastasis even after being serially transplanted from one mouse to another without any further exposure to palmitic acid.

“I think it is too early to determine which type of diet could be consumed by patients with metastatic cancer that would slow down the metastatic process,” said Benitah in a press statement. “That said, based on our results one would think that a diet poor in palmitic acid could be effective in slowing down the metastatic process, but much more work is needed to determine this.”

The researchers think the exposure to palmitic acid changed the epigenetics of the cancer cells creating a ‘prometastatic memory’ linked to methylation changes around the fatty acid transporter CD36. The team are now looking for ways to block this kind of cellular change.

Benitah is a co-founder of a biotech startup called ONA Therapeutics, also based in Barcelona. Last year the company raised €30M ($35M) in Series A funding to develop antibody-based therapies for metastatic cancer.

“If things keep on going as planned, we could start the first clinical trial in a couple of years. I am very excited about this and we are investing a lot of effort to generate the best possible therapy that cancer patients will hopefully be able to benefit from in the nearby future,” commented Benitah.