Carcinogens can be classified into several categories, including chemical, physical, and biological agents.
Chemical carcinogens: These include substances like tobacco smoke, asbestos, benzene, and formaldehyde. Many are industrial chemicals or byproducts of combustion. Physical carcinogens: Examples include radiation from ultraviolet rays, radon, and X-rays, which can damage cellular DNA. Biological carcinogens: Certain viruses, bacteria, and parasites can contribute to cancer development by triggering chronic inflammation or causing direct genetic damage. Notable examples are human papillomavirus (HPV) and Helicobacter pylori.
