IARC group 1

IARC Group 1

The International Agency for Research on Cancer (IARC) is a specialized agency of the World Health Organization (WHO) that conducts and coordinates research into the causes of cancer. One of its key functions is to evaluate the carcinogenic risks of various substances, mixtures, and exposures to humans. These evaluations are published in the IARC Monographs, which classify agents into different groups based on the strength of evidence for their carcinogenicity.

IARC Group 1 is the classification for agents that are "carcinogenic to humans." This is the highest level of certainty in the IARC classification system, indicating that there is sufficient evidence from epidemiological studies to support a causal relationship between exposure to the agent and cancer in humans.

Criteria for Classification

The classification of an agent into IARC Group 1 is based on a comprehensive review of the available scientific evidence. The criteria include:

• Sufficient evidence in humans: This means that a causal relationship has been established between exposure to the agent and cancer in humans. The evidence is usually derived from epidemiological studies that show a consistent association between the agent and an increased risk of cancer.

• Sufficient evidence in animals: While human data is paramount, evidence from animal studies can also contribute to the classification. If there is sufficient evidence of carcinogenicity in experimental animals, this can support the classification, especially if the mechanism of carcinogenesis is understood and relevant to humans.

• Mechanistic and other relevant data: Mechanistic data can provide insights into how an agent causes cancer. This includes information on the agent's ability to cause genetic mutations, induce cellular proliferation, or disrupt normal cellular processes.

Examples of IARC Group 1 Agents

Some well-known examples of agents classified as IARC Group 1 include:

• Tobacco smoke: The carcinogenicity of tobacco smoke is well-established, with strong evidence linking it to cancers of the lung, mouth, throat, esophagus, and several other organs.

• Asbestos: Exposure to asbestos fibers is linked to mesothelioma, a rare cancer of the lining of the lungs, as well as lung cancer and other cancers.

• Alcoholic beverages: Consumption of alcoholic beverages is associated with an increased risk of cancers of the oral cavity, pharynx, larynx, esophagus, liver, colorectum, and breast.

• Ultraviolet (UV) radiation: UV radiation from the sun and artificial sources is a major cause of skin cancers, including melanoma.

Implications of IARC Group 1 Classification

The classification of an agent as IARC Group 1 has significant public health implications. It often leads to regulatory actions aimed at reducing exposure to the agent. For example, the classification of tobacco smoke as a Group 1 carcinogen has led to widespread public health campaigns and regulations to reduce smoking rates.

Also see

• IARC Monographs
• Carcinogen
• Cancer prevention
• Epidemiology
• Public health