By Craig Weatherby
Breast cancer is the most common form of cancer in women worldwide.
Behaviors appear to affect cancer risk, with about one-third of cases linked to poor diet and lifestyle choices.
And growing evidence suggests that early exposure to omega-3 fatty acids from fish (DHA and EPA) may curb breast cancer risks (MacLennan M et al. 2010).
For more on that, see “Omega-3s: Start ‘em Early to Stop Breast Cancer”, and our “Foods and breast risk” sidebar.
Conversely, diets high in omega-6 fats from vegetable oils appear to raise the risk … see “Breast Cancer and Omega-3s: More Encouraging Evidence” and “Breast Cancer Tied to Omega Imbalance … Again”.
Breast cancers differ in dangerousness
Breast cancers fall into two major classes ... both dangerous, but one inspires dread.
Tumors that feature cells with estrogen receptors are call “ER-positive”. They're potentially deadly, but often treatable or curable.
The one-third of breast tumors that lack estrogen receptors are called “ER-negative”. These aggressive cancers resist treatment and have poor prognoses.
About 15 percent of ER-negative cancers are “triple-negative” tumors, whose cells lack receptors for any of the three hormones that fuel ER-positive cancers: estrogen (ER), progesterone (PR), and human epidermal growth factor.
Based on very preliminary research, targeted nutrition may help prevent and/or treat triple-negative tumors. For example, see “Vitamin D Lack Linked to Killer Breast Cancer” and “Does Coffee Curb Breast Cancer?”.
Now, a cell study suggests that omega-3 fatty acids from fish may be allies against these tough-to-treat breast tumors.
Toughest tumors may respond to omega-3s
Scientists from Fox Chase Cancer Center set out to see whether fish-source omega-3s would work better or worse against triple-negative breast cancer cells, versus cells from other types of the disease (Pogash T et al 2013).
Specifically, they wanted to test whether omega-3s from fish (EPA and DHA) and their metabolites would slow or stop the creation of new cells (proliferation) in different kinds of tumors.
(When omega-3s get absorbed into a cancer cell, they're broken down into smaller molecules called metabolites.)
So the Fox team tested the effect of omega-3 EPA and DHA and their metabolites on three ER-positive cell lines and seven triple-negative cell lines.
The omega-3s worked against all types of cancer cells. But as the Fox Center said, the impact of omega-3s was “dramatically more pronounced” against triple-negative tumor cells.
Encouragingly, fish-derived omega-3s curbed cell-proliferation in triple-negative tumors by up to 90 percent.
In addition, omega-3 metabolites cut the triple-negative breast cancer cells' ability to move by 20 to 60 percent.
This study is part of a collaboration between Fox Chase Cancer Center and Pennsylvania State University under a five-year grant awarded by the Komen Foundation.
Andrea Manni, M.D., leader of the Pennsylvania State University team, is currently testing the effects of omega-3s and its metabolites on triple-negative breast cancer in rodents.
We'll let you know how those studies turn out.
Positive results may lead to human clinical trials … the only way to be certain that omega-3s can help fight triple-negative breast cancers.
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  • Fox Chase Cancer Center (FCCC). Omega-3 Fatty Acids More Effective at Inhibiting Growth of Triple-Negative Breast Cancer than of Luminal Breast Cancers. April 9, 2013. Accessed at
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