Definition of Carcinogenicity:
- Carcinogenicity refers to the ability of a substance to induce or increase the incidence of cancer.
- A carcinogen can be a chemical, physical agent (like radiation), or biological agent (like certain viruses).
Stages of Carcinogenesis:
- Initiation: A mutagenic event leads to genetic changes in cells.
- Promotion: The altered cells are stimulated to divide and expand, often influenced by promoters that themselves may not be mutagenic but encourage proliferation.
- Progression: Further mutations lead to malignant transformation, enabling cells to invade tissues and metastasize.
Classification of Carcinogenicity:
- Agencies like the International Agency for Research on Cancer (IARC) classify carcinogens into groups (e.g., Group 1 – carcinogenic to humans, Group 2A – probably carcinogenic, etc.).
Examples:
- Tobacco smoke (contains multiple carcinogens like benzopyrene).
- Asbestos fibers.
- Benzene (associated with leukemia).
Advertisements
- Tamoxifen: While used to treat breast cancer, long-term use has been associated with an increased risk of endometrial cancer in some patients.
