Colorectal cancer in young adults may be linked to weed killer

Key Points:

• New research from Spain suggests that exposure to the herbicide picloram, widely used since the 1960s, may be linked to the rising rates of early-onset colorectal cancer, particularly in people under 55.
• The study analyzed epigenetic marks in DNA and found a distinct association between picloram exposure and early-onset colorectal cancer, with tumors showing fewer mutations in the APC gene, indicating a potentially different cancer development pathway.
• Picloram mimics plant growth hormones and persists in soil for months to years, meaning younger patients likely had more prolonged exposure than older patients, which may explain the age-related differences in cancer incidence.
• While the study is observational and cannot confirm causation, it highlights picloram as a new risk factor worth further investigation and suggests potential regulatory implications if a causal link is established.
• Colorectal cancer cases are increasing among younger adults in the US, with nearly half of new diagnoses expected in people under 65, underscoring the urgency of identifying and mitigating emerging environmental risk factors.