Their findings identify a new genetic mechanism that could explain the link between diet, and particularly certain fats, and breast cancer, the most frequent form of cancer in women around the world.
Nutritional factors have long been considered important in the development of breast cancer. Higher rates of the disease in the developed world support the impact of lifestyle and environmental factors, such as high consumption of animal and certain vegetable fats.
But now researchers at the Departament de Biologia Cellular, de Fisiologia i d'Immunologia of the Universitat Autonoma of Barcelona have identified four genes, one which has a completely unknown function, whose expression may be involved in the impact of dietary lipids.
Using microarrays, they compared the expression of 6,000 genes in breast cancer tumours in animals fed with omega-6 rich diets (corn oil) and in animals with low-fat diets. The tumours in the rats with the fat-rich diets proliferated, on average, more than the others, apparently associated with a lesser expression of four genes.
Three of these genes are related to cellular differentiation (a-2u-globulin, VDUP1 and H19) and the fourth is a sequence with a totally unknown function (known as EST Rn.32385).
Describing the research in the June issue of Molecular Carcinogenesis (40(2):73-8), the scientists say "this is the first time that the influence of a fat-rich diet on the expression of these genes has been investigated".
"The discovery opens a new line of research into its implication in changes on the state of cellular differentiation induced by dietary lipids in breast cancer tumours and the degree of malignity of the cancer."
However lead researcher Dr Eduard Escrich, also head of the Grup Multidisciplinari per a l'Estudi del Càncer de Mama (Multi-disciplinary group on Breast Cancer Studies) told NutraIngredients.com: "Eating lots of these fats doesn't mean we get cancer. But if we already have it, they can accelerate it."
"However it is important that we still eat omega-6 fats as these are essential fatty acids and we cannot manufacture them. What is most important is that all fats do not make up more than 30 per cent of our diet, and that we try to eat more of those found in oily fish and olive oil, rather than saturated fats."
More extensive research into the genes will help to discover whether the new mechanism works in the same way in human breast cancer as in animals.