Environmental and occupational cancer: highlighting research contributions from the IARC on its 60th anniversary

Approximately half of cancers are attributed to modifiable risk factors or inherited genetic mutations, thus there remains the potential for as-yet unidentified environmental risk factors to explain substantially more of the global cancer burden. Current estimates of the environmental and occupational cancer burden account for a relatively small number of exposures, because of challenges in characterizing exposure patterns and human cancer risks. Hence, the environmental cancer burden may be underestimated because of combinations of not having identified all carcinogenic agents, lack of understanding of cancer risks at very low exposure levels of even known carcinogens, and lack of understanding of joint effects. The International Agency for Research on Cancer has a long history of addressing these challenges, and of advancing our understanding of occupational and environmental causes of cancer, with primary research predominantly conducted by the Environment and Lifestyle Epidemiology Branch. The International Agency for Research on Cancer's position within the World Health Organization has facilitated the conduct of cross-border collaborations on important and sensitive topics, ranging from asbestos, ionizing radiation, and pesticides to its current work on artisanal petroleum refining. Here, we highlight some important Environment and Lifestyle Epidemiology contributions to several areas of occupational and environmental cancer, describe recent progress in other important and emerging exposures, and finally, provide suggestions for future research. In our constantly changing world, with new products, technologies, and demands transforming our environment and workplaces, there is a continued need for high-quality human cancer investigations of potential occupational and environmental carcinogens, especially those characterizing environmental levels of exposure encountered by the general population in their daily life and in underresearched regions of the world.