Every year, almost 3500 Danish women are diagnosed with breast cancer. Approximately 20% of them have a particularly aggressive type of cancer which can be feared to have metastasized if the lymph nodes in the armpit during surgery are found to contain cancer cells. The aggressive cancer is caused by a gene in the affected women being very active and producing large amounts of the protein HER2. When HER2 is deposited on the surface of a breast cell, it reacts with growth substances in the blood which can transform the cell into a cancer cell and stimulate it into growing.
Since 1998, however, there has been a medication which works the same way as an antibody in that it can block HER2 and thereby prevent the growth stimulation. The medication is called Herceptin® (Trastuzumab) and has thus far only been offered to women who, besides being "HER2 positive", have had relapses after being treated for metastasized breast cancer.
Very recently, however, studies have shown that the beneficial effect of Herceptin can take place far earlier; namely as soon after the operation as the woman is found to be HER2 positive. In Denmark, this treatment can be an option for approximately 450 women a year. In a study involving 3350 women who were given Herceptin for a year, the risk of a relapse was reduced by 50% and mortality was reduced by 33%. In a Belgian study including 5000 women, the risk of relapse was also reduced by 50% - to approximately 6%. Total mortality rate was reduced in this study as well, but only slightly and not with statistical significance.
The Danish Cancer Society now encourages women who have been operated for breast cancer to find out if they are HER2 positive and thereby should receive the treatment. Unfortunately it is not as harmless as it might seem. HER2 is also important to the cardiac function and chemotherapy in combination with a blocking of HER2 is a cocktail that can cause a weakened heart. This happens in up to 20% and many women have to stop using the medicine for this reason. How they do in the long run is not known.
GLA and Herceptin co-operate
All this information is to say that HER2 apparently - sensationally - can also be attacked from an altogether unexpected angle. The vital fatty acid gamma-linoleic acid (GLA) which is used as a dietary supplement by many people is also (in laboratory studies) found to be able to inhibit HER2 but through another mechanism than that of Herceptin. According to researchers at Northwestern University in the US, GLA enhances the effect of Herceptin no less than 30 - 40 times without harming healthy cells. The combination causes a lot of cancer cells to die while others are inhibited in their growth.
The mode of operation is complicated. The studies indicate that GLA stimulates the production of a protein (PEA3) which inhibits the gene that produces HER2. As GLA and Herceptin therefore each have their own point of intervention; one by blocking the production of HER2, the other by blocking its effect - they enhance each other's effect. Earlier studies have shown that GLA in the laboratory is also able to inhibit cancer on its own.
If only some of this applies to living human beings, it is a true sensation. However, it should be emphasized that so far the studies have only involved laboratory tests on a cellular level. More extensive research in this field is required as the authors point out. What women who suffer from HER2 positive breast cancer should do for the time being, therefore, is an individual decision.
References:
Piccart-Gebhart et al. Trastuzumab after adjuvant chemotherapy in HER2-positive breast cancer. N Engl J Med 2005;353:1659-72.
Romond EH et al. Trastuzumab plus adjuvant chemotherapy for operable HER2-positive breast cancer. N Engl J Med 2005;353: 1673-84.
Menendez JA et al. Effect of gamma-linolenic acid on the transcriptional activity of the Her2/neu (erbB-2) oncogene. J Natl Cancer Inst 2005;97:1611-15.
