Report identifies gaps in research for 20 suspected carcinogens

PCBs, diesel exhaust among agents identified as focus of further research

A new report from the American Cancer Society and other world-leading health groups identifies gaps in research for 20 suspected carcinogens whose potential to cause cancer is as yet unresolved. The report is designed to prioritize agents for additional research, and to lead to well-planned epidemiologic or mechanistic studies leading to more definitive classification of these agents.

The report, "Identification of research needs to resolve the carcinogenicity of high-priority IARC carcinogens," is a concerted effort to identify ways to close existing gaps in knowledge for particular agents classified by the International Agency for Research on Cancer (IARC) by identifying information needs and the research to address them for 20 selected agents. The agents are generally in IARC Groups 2A, 2B, and 3. The project originated as part of the National Institute for Occupational Safety and Health's (NIOSH) National Occupational Research Agenda (NORA) to enhance occupational cancer research, and involved collaboration with IARC, the American Cancer Society, the National Institute of Environmental Health Sciences (NIEHS), and the National Cancer Institute (NCI). The effort was co-sponsored by the American Cancer Society. The agents prioritized as needing additional study are:

• Lead and lead compounds
• Indium phosphide
• Cobalt with tungsten carbide
• Titanium dioxide
• Welding fumes
• Refractory ceramic fibers
• Diesel exhaust
• Carbon black
• Styrene-7,8-oxide and styrene
• Propylene oxide
• Formaldehyde
• Acetaldehyde
• Dichloromethane, methylene chloride (DCM)
• Trichloroethylene (TCE)
• Tetrachloroethylene (perc, tetra, PCE)
• Chloroform
• Polychlorinated biphenyls (PCBs)
• Di(2-ethylhexyl) phthalate (DEHP)
• Atrazine
• Shift work

"There is significant concern among the public about substances or exposures in the environment that may cause cancer, and there are some common occupational agents and exposure circumstances where evidence of carcinogenicity is substantial but not yet conclusive for humans," said Elizabeth Ward, Ph. D., vice president, Surveillance and Health Policy Research at the American Cancer Society and lead author of the report.. "The objectives of this report are to identify research gaps and needs for 20 agents prioritized for review based on evidence of widespread human exposures and potential carcinogenicity in animals or humans." Dr. Ward, one of the organizers of the meeting and lead author of a version of the report that appears in the journal Environmental Health Perspectives, added that the report highlights the importance of research in occupational settings for the identification of human carcinogens as well as the need for funding and access to populations for this work to continue.

Source: American Cancer Society