Carcinogena

Carcinogena is a term used to describe substances, agents, or exposures that can cause cancer by promoting carcinogenesis. These agents may act directly by damaging DNA or indirectly by affecting cell growth, inflammation, or hormonal balance. Cancer development is a multistep process in which genetic and epigenetic changes accumulate over time, and carcinogenic exposure can influence one or more steps in this process.

Common examples of carcinogenic agents include tobacco smoke, ultraviolet and ionizing radiation, asbestos, arsenic, benzene, formaldehyde, and aflatoxins. Diet, occupation, environmental pollutants, certain pharmaceuticals, and viral or microbial factors can also contribute to cancer risk through carcinogenic mechanisms.

Carcinogens reach their targets through various routes, such as inhalation, ingestion, skin contact, or injection. They may act as genotoxic carcinogens, which form DNA adducts and mutations in critical genes, or as non-genotoxic carcinogens, which promote cancer by chronic inflammation, increased cell turnover, hormonal effects, or immune suppression. The latency period between exposure and cancer diagnosis can be long, sometimes spanning decades.

International health agencies classify carcinogens based on evidence of cancer causation. The IARC system identifies Group 1 agents as carcinogenic to humans, Group 2A as probably carcinogenic, Group 2B as possibly carcinogenic, Group 3 as not classifiable, and Group 4 as probably not carcinogenic. Risk assessment considers the strength of evidence, exposure level, and population burden. Reducing exposure to known carcinogens is a key public health goal to lower cancer incidence.