Background: Regarding the multifactorial etiology of breast cancer, food choices, as well
as dietary intake, are the main modified factors in cancer prevention. In this sense, understanding
molecular pathways involved in breast cancer proliferation can help determine the mechanisms of
action of organic compounds such as antioxidant vitamins that are known to protect against cancer.
Objective: Assess the mechanism of action of vitamin E in breast cancer modulation, with emphasis
on important markers of tumor development.
Methods: It is a systematic review carried out in PubMed and Web of Science databases, from the
last 5 years, in Portuguese, English and Spanish. The following terms were selected according to The
Medical Subject Headings (MeSH): “breast cancer” OR “breast neoplasms”, “tocopherol” OR
“tocotrienols” OR “vitamin E”, as equated terms.
Results: A total of 595 articles were found and 25 were selected according to inclusion criteria.
Vitamin E has been related to suppression/overexpression of important tumorigenic pathways,
mainly associated with proliferation, energy metabolism, chemosensitivity and invasion/metastasis.
Clinical studies of vitamin E supplementation are needed to assess the dose/response effect on breast
Conclusion: The safety of vitamin E supplementation is still controversial due to current studies design
available. However, when vitamin E is supplemented, the dose and therapeutic regimen must be
carefully decided, including the route of administration and breast cancer subtypes to enhance
desired effects and minimize unwanted side effects.