Selenium may prevent hereditary breast cancer

Approximately every 20th case of breast cancer is caused by inheritance. Most often, the cause is an inborn mutation of the so-called BRCA1 gene which, under normal circumstances, repairs damaged chromosomes.
If you are a carrier of this mutation, your risk of developing breast cancer even as a young woman will be increased: Approximately 60% will develop the disease before they are 50 years old and 85% will have developed it before the age of 70. At the same time, the risk of ovarian cancer is no less than 60%.
Being born with this mutation puts women in a very difficult situation as they have tough decisions to make. Some women choose to prevent developing breast cancer by having their breasts and ovaries removed at an early age while others wait and see if they are among the unfortunate majority. Women carrying the mutation will have to think about having children at an early age if they wish to maintain their possibility of breast-feeding. There is no certainty as to if or when the cancer might suddenly appear.
However, a highly interesting Polish study now indicates that the risk of developing breast cancer when carrying the mutation of the BRCA1 gene can be significantly reduced by taking a simple selenium supplement. The supplement drastically reduces the frequency of chromosomal damages in women with this inborn mutation. If the results hold water, women can buy themselves time and reduce their risk of unstability in the protective chromosomes.
The study was carried out at the Pomeranian Academy of Medicine in Szczecin, Poland. It consisted of measuring the number of mutations - so-called chromosome breaks - in white blood cells that were exposed to "chemical radiation" in the form of the chemotherapeutic drug bleomycin in the laboratory.
Two studies were carried out. One study compared chromosome breaks in 26 women with and 26 women without the inborn mutation. In the first group, 0.59 breaks per cell were measured while women without the mutation only had an average of 0.39 breaks per cell.
35 other women who were all carrying the mutation participated in the other study. Half of them were given a daily supplement of 280 mg. of selenium. After 1 - 3 months, a blood test was taken in order to expose their blood cells to bleomycin as well. The results were almost identical to the first study: In the blood cells of the women who had not taken selenium, 0.63 chromosome breaks per cell were found whereas only 0.4 breaks per cell were found in the white blood cells of the ones who had taken selenium.
In other words, women with inherited mutations could normalize the stability of their chromosomes by simply taking a daily selenium supplement. Now, the question is how to interpret these results. Does this mean that their cancer risk was reduced as well?
There are many indications that this is the case, but complete certainty does not exist. Researchers have concluded that hereditary breast cancer is partly caused by unstable chromosomes. Other researchers have found that breast cancer patients have distinctly more chromosome deviations in their white blood cells compared to healthy women. Moreover, several studies have indicated a connection between the sensitivity towards cancer in general and the level of chromosome breaks.
Furthermore, another study showed that among 3812 workers who were exposed to mutagenic substances, the ones with the most chromosome deviations were also the ones most likely to develop cancer later in life. The evidence seems to be numerous.
Selenium has antioxidant effects and in several studies it has also displayed anti-carcinogenic abilities. Since the soil in Poland is very low - just as is the case in the UK - researchers believe that a similar study in other countries where the selenium content of the soil is different might provide a different result.
The trial subjects were given what equals about three ordinary selenium tablets of organic selenium a day. This dose does not exceed what is permissible.
Reference:
Kowalska E et al. Increased rates of chromosome breakage in BRCA1 carriers are normalised by oral selenium supplementation. Cancer Epidem Biomarkers Prev 2005;14(5):1302-6.