Carcinogenic refers to any substance or agent that has the potential to cause cancer in living tissues. The mechanism by which carcinogens cause cancer can be complex and varies depending on the substance but often involves alterations to cellular DNA. Exposure to carcinogens can come from various sources including certain chemicals, radiation, and even some viruses. These agents can lead to carcinogenesis by inducing mutations, promoting uncontrolled cell growth, or interfering with cell signaling pathways.

Carcinogens are classified by various agencies based on the strength of evidence regarding their cancer-causing potential. For instance, the International Agency for Research on Cancer (IARC), which is part of the World Health Organization, classifies substances into groups ranging from Group 1 (known to be carcinogenic to humans) to Group 4 (probably not carcinogenic to humans).

For more in-depth information on carcinogens and carcinogenicity, you can visit:

1. National Cancer Institute (NCI): Provides comprehensive information about cancer-causing substances, the science of carcinogens, and related public health information.
URL: https://www.cancer.gov/about-cancer/causes-prevention/risk/substances

2. International Agency for Research on Cancer (IARC): Offers detailed scientific reports on the classification and evaluation of carcinogenic risks to humans from a variety of agents.
URL: https://www.iarc.fr/cards_page/monographs/

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