A compound found in certain foods may be a cause of testicular cancer in young men, according to new research published in this month's Cancer Causes and Control journal.
Cancer researcher Gary G. Schwartz proposes that exposure to a common carcinogen called ochratoxin A during childhood or even before birth may set up the testes so that testicular growth during puberty triggers the launch of testicular cancer. Vitamins A, C and E should be taken by pregnant women to reduce the toxicity of the compound.
Ochratoxin A develops in mould that grows in grains and coffee beans and is found in animals that consume mouldy grain, especially pigs.
"Little is known about the etiology of testicular cancer, which is the most common cancer among young men," said Schwartz, associate professor of cancer biology and public health sciences at Wake Forest University in the US. The cancer is most prevalent among men aged between 14 and 34. Schwartz said that epidemiologic data point to exposure either in the womb or early in life, "but the nature of the exposure is unknown."
The theory suggests that exposure to ochratoxin A begins during pregnancy or early childhood, which leads to damage to testicular DNA. Ochratoxin A is then transferred through the placenta to the foetus, and is also present in mothers' milk, so infants could be exposed through breastfeeding. The DNA changes remain dormant until testicular growth at puberty promotes these changes in testicular DNA into cancer.
The solutions proposed by Schwartz would rely on public health to reduce exposure to ochratoxin A or reduce the genotoxicity of ochratoxin A exposure. Vitamins A, C and E could be given to pregnant women to reduce the toxicity of ochratoxin A, and drugs like aspirin or indomethacin would have a similar effect.
"These agents, in animals at least, markedly reduce the DNA damage caused by ochratoxin A," Schwartz said. Aspartame, the artificial sweeter, is similar structurally to ochratoxin A, and is a potent ochratoxin A antagonist.
It has been found that testicular cancer is a disease of young white men, and it shows marked geographic variation. For instance, the incidence is higher among northern Europeans than central or southern Europeans. Schwartz noted that grains grown in northern Europe are more likely to be contaminated because weather conditions during harvest season cause mould.
The highest rate of testicular cancer in Europe is in Denmark, where there are 7.8 cases per 100,000 per year. Consumption of pork products in Denmark is among the highest in the world, and Danes also eat the most rye, the cereal grain that is most often contaminated by ochratoxin A.
Schwartz noted another interesting element: testicular cancer is more common among people of higher socioeconomic levels. These are the groups most likely to breastfeed.
"We propose that exposure to ochratoxin A-contaminated food provides a coherent explanation for much of the descriptive epidemiology of testicular cancer," Schwartz said, adding that future studies of testicular cancer "should focus on breastfeeding practices and the consumption of ochratoxin A containing foods such as cereals, pork products, milk and coffee by mothers and their male children."
See Cancer Causes and Control for more details.