The omega-6 fatty acids arachidonic acid (found primarily in meat and meat products) and linoleic acid (found in vegetable oils) both have been shown to promote breast cancer development. Linoleic acid is converted into arachidonic acid in the body. However, the breast cancer connection is not straightforward since omega-6 fats are essential to health.
The ratio of omega-6 to omega-3 fats in the diet appears to be more important than the absolute amounts of these fatty acids. Now a new study has described a mechanism of action by which arachidonic acid promotes breast cancer development.

Latest research helps explain how arachidonic acid promotes breast cancer

The study referenced at the beginning of this news article was designed to investigate the role of arachidonic acid in breast cancer development and angiogenesis. Arachidonic acid and its metabolites are known to promote the development of breast cancer, but the mechanisms of action is not well understood. The mammalian target of rapamycin (mTOR) signaling pathway is upregulated during the development of many cancers, including breast cancer.
The authors demonstrated that arachidonic acid effectively activated both mTOR complex 1 (mTORC1) and mTORC2 in breast cancer cells. Additional experiments demonstrated that mTOR activity was required for arachidonic acid-stimulated cell proliferation and angiogenesis. In an animal model of breast cancer, rapamycin, an mTOR inhibitor, was shown to reduce arachidonic acid-enhanced rat mammary incidence, tumor weight, and angiogenesis.
The authors conclude that arachidonic acid appears to stimulate mTOR in breast cancer cells and that arachidonic acid-activated mTOR plays critical roles in tumorigenesis and angiogenesis of breast cancer.