Influence of fatty acid‐free diet on mammary tumor development and growth rate in HER‐2/neu transgenic mice

Abstract

Numerous investigations have found a relationship between higher risk of cancer and increased intake of fats, while results of clinical studies of fat reduction and breast cancer recurrence have been mixed. A diet completely free of fats cannot be easily administered to humans, but experimental studies in mice can be done to determine whether this extreme condition influences tumor development. Here, we examined the effects of a FA-free diet on mammary tumor development and growth rate in female FVB-neu proto-oncogene transgenic mice that develop spontaneous multifocal mammary tumors after a long latency period. Mice were fed a fatty acid-free diet beginning at 112, 35, and 30 days of age. In all these experiments, tumor appearance was delayed, tumor incidence was reduced and the mean number of palpable mammary tumors per mouse was lower, as compared to standard diet-fed mice. By contrast, tumor growth rate was unaffected in mice fed the fatty acid-free diet. Plasma of mice fed the fatty acid-free diet revealed significantly higher contents of oleic, palmitoleic and 20:3ω9 acids and lower contents of linoleic and palmitic acids. In conclusion, these findings indicate that a FA-free diet reduces tumor incidence and latency but not tumor growth rate, suggesting that a reduction in dietary FAs in humans may have a protective effect on tumorigenesis but not on tumors once they appear.

Tumor-linked HER2 expression: association with obesity and lipid-related microenvironment

“…Furthermore, consumption of eicosapentaenoic acid drastically reduced serum leptin levels. Another dietary intervention study on this transgenic mouse model observed that a fatty acid-free diet reduced tumor incidence and delayed tumor appearance but tumor growth rate was unaffected [144]. A recent report has shown that caloric restriction elicited an increase in mammary ERα and ERβ expression in MMTV-neu transgenic mice in comparison with overweight (high-carbohydrate, low-fat diet) and diet-induced obesity (high-carbohydrate, high-fat diet) regimen [145].…”

Biological and Nutritional Properties of Palm Oil and Palmitic Acid: Effects on Health

“…Different effects of SFAs, such as PA, and MUFAs, have been reported on cell proliferation and tumor development also in in vitro and animal studies [110,111]. The conflicting results may be due to a combined administration in animals of different FAs.…”

“…Interestingly, Rossini et al demonstrated in mice that a FA-free diet reduces mammary tumor incidence but not tumor growth rate [111]. Because humans are not able to comply with a FA-free diet, Rossini’s study suggests that a low-fat diet might play a protective role in tumorigenesis but no effects should be expected on already established tumor masses.…”

Oleic acid induces migration through a FFAR1/4, EGFR and AKT-dependent pathway in breast cancer cells

“…Epidemiological studies strongly suggest an association between a higher intake of dietary fat and obesity with an increased risk of developing breast cancer. Moreover, obesity is characterized for an elevation of circulating free fatty acids (FFAs) (1, 2, 3, 4). FFAs are an energy source, and induce activation of signal transduction pathways in breast cancer cells (5, 6, 7, 8).…”