After a Century of Research into Environmental Mutagens and Carcinogens, Where Do We Stand?

Our plain-English summary of After a Century of Research into Environmental Mutagens and Carcinogens, Where Do We Stand?, by J.D. Vitorino, P.M. Costa (International Journal of Environmental Research and Public Health, 2023).

The study

• Authors: J.D. Vitorino, P.M. Costa
• Journal: International Journal of Environmental Research and Public Health
• Published: 2023;20(2)
• Type of article: Review
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Cancer is one of the longest-known human diseases, yet only in recent times have we begun to perceive that the percentage of neoplasms caused by environmental factors, lifestyle and chemicals, is likely underestimated. The first medical reports associating cancer with pollutants like tars appeared by the early 20th century, but despite initial evidence relating oncogenesis and chromosomal alterations, only after the structure of DNA had been elucidated in the 1950s have genetic disorders been fully perceived as cause. This led to a growing interest in genotoxic and mutagenic pollutants. Even though we are now familiar with a range of environmental carcinogens spanning between aromatic hydrocarbons and asbestos to radionuclides and forms of carbon nanomaterials, establishing causal networks between pollutants and cancer remains cumbersome. In most part, this is due to the complexity of toxicant matrices, unknown modes-of-action of chemicals or their mixtures, the widening array of novel pollutants plus difficulties in subtracting background effects from true aetiology of disease. Recent advances in analytical chemistry, high-throughput toxicology, next-generation sequencing, computational biology and databases that allocate whole normal and cancer genomes, all indicate that we are on the verge of a new age of research into mechanistic 'oncotoxicology', but how can it impact risk assessment and prevention?

In plain English

This article was a short narrative review, not a new study. Written mainly for toxicologists, it summarised the history of research into environmental chemicals that cause mutations and cancer, from early observations to modern laboratory methods. One section discussed asbestos, which the authors described as a group of six silicate minerals. They wrote that asbestos had been associated with lung disease since the late 19th century but that building a solid body of evidence took more than 50 years. They recounted earlier work by others, including a 1950s statistical study by Doll linking lung cancer with occupational asbestos exposure, and a 1964 New York Academy of Sciences conference. They described mesothelioma as a pleural malignancy that seems to be caused only by asbestos exposure, and stated that how mesothelioma forms is still not agreed. The review did not name specific fiber types. It also covered arsenic, cadmium, polycyclic aromatic hydrocarbons, glyphosate and carbon nanotubes. The authors concluded that understanding mechanisms, through an approach called Adverse Outcome Pathways, could help predict cancer risk from new chemicals more quickly.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Short narrative review (no new data collected)
• Who was studied: No study population. The authors reviewed historical and current research on environmental mutagens and carcinogens.
• Exposure: Environmental carcinogens in general. Asbestos (not broken down by fiber type), arsenic, cadmium, polycyclic aromatic hydrocarbons, glyphosate, multi-walled carbon nanotubes and others were discussed as case studies.
• Main results:
  • The authors stated that asbestos has been associated with lung disease since the late 19th century, and that building a solid body of evidence took more than 50 years.
  • The review recounted that, in the 1950s, Doll (a study by others) used statistics to associate lung cancer with occupational asbestos exposure.
  • The authors described mesothelioma as a pleural malignancy that seems to be caused only by asbestos exposure.
  • The authors stated that the mechanism by which mesotheliomas form is still not agreed, and may involve oxidative stress, inflammation or interference with the tissues' proteins.
  • The authors stated that the International Agency for Research on Cancer (IARC) now lists more than 500 agents in Groups 1, 2A and 2B, out of 1000 assessed.
• The authors' conclusion: The authors concluded that understanding mechanism is essential to determining risk. They proposed that investigating Adverse Outcome Pathways for various cancer types could help predict carcinogenic risk for new chemicals and materials, and could shorten the delay between a product's release and safety measures.
• Limitations the authors state:
  • The authors stated that the review was short and was not an extensive biomedical or epidemiological appraisal of chemically induced cancer.

Topics

Medical terms in this study, explained in our Lexicon: Neoplasm, Oncogenesis, Next-Generation Sequencing (NGS).

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• Risk-based indicators of Canadians' exposures to environmental carcinogens — E. Setton, P. Hystad, et al. (2013)
• Evaluation of environmental carcinogens for cancer in man — A.L. Brown (1976)
• Identification of environmental carcinogens utilizing T-cell mediated immunity — R.H. Stevens, D.A. Cole, et al. (1986)

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