Making Sense of Carcinogens
In a new article published in the journal Environmental Health Perspectives, Carol Potera detailed a workshop organized by the International Agency for Research on Cancer (IARC) which applied “a new method to create order among a sprawling body of mechanistic data, based on 10 key characteristics of human carcinogens.
This method involves evaluating certain class 1 carcinogens (those definitely known to cause cancer) and their ability to:
1) Act as an electrophile (i.e., metabolic activation); 2) induce DNA damage and/or mutation (genotoxicity); 3) alter DNA repair or cause genomic instability; 4) induce epigenetic changes; 5) induce oxidative stress; 6) induce chronic inflammation; 7) suppress the immune system; 8) modulate receptor-mediated effects; 9) cause cell immortalization; and 10) alter a cell’s proliferation, death or nutrient supply. Potera observed that any given carcinogen exhibits “at least one of these characteristics.”
The chemicals chose for evaluation here were benzene and polychlorinated biphenyls (PCBs). The attached chart demonstrates the results. Once again, we see benzene as a model human carcinogen. The reason becomes clear with research. The group found more than 1,800 mechanistic studies for benzene and almost 3,900 for PCBs. Benzene acted on 8 of the 10 mechanisms and PCBs acted on 7.
Renowned expert Martyn Smith, a professor of toxicology at the University of California, Berkeley, is quoted as saying that this method “proved an incredibly useful tool for dividing up several thousand scientific papers into manageable amounts of information for people to review and opine on.”
The hope is that eventually this method will create a more organized method for understanding a chemical’s carcinogenic potential and benefit humanity through awareness and prevention.
The article can be found at http://ehp.niehs.nih.gov/wp-content/uploads/124/6/ehp.124-A113.alt.pdf .