Variants of Genes associated with the Essential Dietary Element Selenium Increase the Risk of Bowel Cancer

Posted on: 26 May 2010

Colorectal cancer or bowel cancer is one of the most significant causes of cancer mortality and morbidity in developed countries. Research suggests that an optimum intake of the trace nutrient selenium may help to prevent   bowel cancer.  TCD  medical research scientist, Dr David Hughes of the School of Medicine,  along with scientists in the UK and Czech Republic  have now  discovered for the first time, that  variations in the genes encoding the proteins by which selenium exerts its biological role (selenoproteins) influence an individual’s risk of developing bowel cancer.  The findings have been recently published  online in the  journal, Carcinogenesis.

Ireland currently has one of the highest mortality rates of bowel cancer in the developed world, and the fifth highest incidence of the cancer in the EU. There are approximately 2,000 diagnosed bowel cancers each year in Ireland, representing a major public health issue.

The study’s new data show that common gene variants in the genes SEPP-1, GPX4 and SELS increase the chance of developing  bowel cancer, highlighting the potentially important role played by selenoproteins and selenium in protecting cells from cancerous growths.

Due to differing soil selenium levels and resultant food content, there is great geographical variation in its intake worldwide and within Europe. As a result the selenium status of many populations across Europe is low compared to other parts of the world, notably much of North America. Worldwide, low selenium intake is correlated with increased bowel cancer incidence. Selenium is a dietary micronutrient that is important for human health. Dietary selenium comes from nuts, cereals, meat, fish  such as tuna, crab, and lobster,  and eggs. 

These new findings will inform the use of selenium supplementation, or increased selenium intake from diet, in European populations as a simple, inexpensive and natural chemo-prevention agent against the cancer.  The study’s examination of the genetic background should define those individuals especially suited to the use of selenium as a cancer prevention strategy, and also for use against cancer recurrence.

Commenting on the significance of the findings, Dr David Hughes stated: “Selenoproteins contribute to keeping healthy cells from turning cancerous.  The variant genetic alleles we have found to be associated with an increased risk of colorectal cancer do so by lowering functional efficiency of particular selenoproteins. However, such effects can be mitigated by an increased selenium intake resulting in better functioning of selenoproteins. The results highlight the important role selenium intake and selenoprotein genotypes play in susceptibility to colorectal cancer. These findings and our planned further research on how these gene variants interact with levels of selenium in the diet have the potential of developing  colorectal cancer prevention protocols by selenium supplementation targeted to at risk geographic areas and genotype groups. The potential benefits to Ireland and the rest of Europe are the possibility of a very inexpensive and practical public health means of preventing colorectal cancer.”

About the research:

Full title and reference of article: ‘Genetic variants in selenoprotein genes increase risk of colorectal cancer’

Carcinogenesis. 2010 Apr 8.