Researchers have discovered how an acid found in palm oil alters the cancer genome, increasing the likelihood the disease will spread.
The scientists have started developing therapies that interrupt this process and suggest a clinical trial could begin in the next couple of years.
The spread of cancer – metastasis – is the main cause of death in patients with the disease and the vast majority of people with metastatic cancer can only be treated, but not cured, researchers say.
Fatty acids are the building blocks of fat in our body and the food we eat.
Metastasis is promoted by fatty acids in the diet, but it has been unclear how this works and whether all fatty acids contribute to the spread of the disease.
The new study, led by researchers at IRB Barcelona, Spain, found one such fatty acid commonly found in palm oil, called palmitic acid, promoted metastasis in mouth cancers and melanoma skin cancer in mice.
Other fatty acids called oleic acid and linoleic acid – omega-9 and omega-6 fats found in foods such as olive oil and flaxseeds – did not show the same effect.
According to the research, neither of the fatty acids tested increased the risk of developing cancer in the first place.
The research found that when palmitic acid was supplemented into the diet of mice, it not only contributed to metastasis but also exerted long-term effects on the genome.
Even when the palmitic acid had been removed from the diet, cancer cells that had only been exposed to it in the diet for a short period of time remained highly metastatic.
Researchers discovered this memory is caused by epigenetic changes to how our genes function..
The changes alter the function of metastatic cancer cells and allow them to form a neural network around the tumour to communicate with cells in their immediate environment and to spread more easily.
By understanding the nature of this communication, the researchers uncovered a way to block it and are now in the process of planning a clinical trial to stop metastasis in different types of cancer.
Professor Salvador Aznar-Benitah, senior group leader at IRB Barcelona and ICREA research professor, and senior author of the paper, said: “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.
“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.
“We are not concentrating on this direction of research, instead we are focusing on new potential therapeutic targets that we could inhibit and that could have a real therapeutic benefit for the patient irrespective of their diet.”
Dr Helen Rippon, chief executive at Worldwide Cancer Research, said: “This discovery is a huge breakthrough in our understanding of how diet and cancer are linked and, perhaps more importantly, how we can use this knowledge to start new cures for cancer.
“Metastasis is estimated to be responsible for 90% of all cancer deaths – that’s around nine million deaths per year globally.
“Learning more about what makes cancer spread and – importantly – how to stop it is the way forward to reduce these numbers.”
The findings are published in the journal Nature and part-funded by the UK charity Worldwide Cancer Research.