Weed Killer Linked to Youth Colon Cancer Rise

A new study published in Nature Medicine proposes a potential link between the herbicide picloram and the concerning rise in colorectal cancer among individuals under 50. Researchers discovered specific DNA methylation signatures in young colorectal tumors that appear to be imprinted by lifelong exposures, including to picloram.

This herbicide, developed in the 1960s and used to eliminate woody plants, was found to persist in soil for years. The study observed that picloram did not appear significantly linked to colorectal cancer in older adults. Its effectiveness in clearing forest during the Vietnam War is also noted.

Comparing pesticide use data with cancer incidence in seven US states revealed picloram as the strongest correlating factor for higher rates of young colon cancer. While glyphosate was a secondary signal, picloram's association was more pronounced.

Scientists acknowledge this observational study cannot definitively prove causation, emphasizing the need for more research. This includes collecting tumor samples from young cancer patients in high-picloram-use areas to further investigate the potential environmental drivers of this trend. Other factors, such as co-formulants in herbicides or bacterial infections, are also being explored.