Positive Health Online

Abstract

SENZAKI and colleagues, Department of Pathology II, Kansai Medical University, Osaka Japan evaluated the effects of dietary fats upon breast cancer growth and metastasis .

Background

Methodology

KPL-1 human breast cancer cells having a propensity for axillary lymph node metastasis when inoculated into the thoracic mammary fat pad of female nude mice were examined. Starting 19 days prior to tumour cell inoculation and continuing until the end of the experiment (43 days following tumour cell inoculation), the mice were fed with one of three semipurified diets containing: 1) 9.5% eicosapentaenoic acid plus 0.5% linoleic acid (EPA diet ); 2) 10% linoleic acid (LA diet ); or 3) 9.5% palmitic acid plus 0.5% linoleic acid (PA diet ) or commercial laboratory chow containing 8.5% fat of which 4.1% was LA, 1.1% was PA, 0.06% was EPA and 3.24% was other (Standard diet ).

Results

Compared to the mice fed the PA or Standard diet, tumour growth was faster and at a higher incidence in the LA diet group and much slower and at a lower incidence in the EPA diet group. Two separate experiments demonstrated identical results. Differences in tumour weight between the LA and PA groups and between the PA and EPA groups were significant at the termination of the experiment, differences caused by differing tumour cell proliferation rates. An in vitro MTT assay demonstrated that fatty acids showed direct stimulatory or inhibitory effects on the KPL-1 cells. Lymph node metastasis was observed in the LA and Standard diet groups, whereas this was not observed in the PA or EPA groups. Body weights were significantly lighter in the LA and EPA groups compared with the PA and Standard diet groups.

Conclusion

These results demonstrate that the EPA diet produced a reduction in tumour cell growth and metastasis whereas the LA diet enhanced these parameters. Dietary fatty acids may therefore play a direct role in the growth and metastasis of human breast cancer, independent of their systemic effects.

References

Senzaki H et al Dietary effects of fatty acids on growth and metastasis of KPL-1 human breast cancer cells in vivo and in vitro Anticancer Res 18(3A): 1621-7 May-Jun 1998.