Carcinogenic Agents

3 stage model of chemical carcinogenesis

Initiation

promotion

progression in neoplastic transformation

Initiation

Change in DNA caused by exposure to a carcinogenic agent

Direct acting carcinogen

Becomes carcinogenic without metabolic conversion

Indirect acting carcinogen

Requires metabolic conversion to become active carcinogen

Promotion

Enhancement of a carcinogenic process through cell proliferation

Chemical metabolized by cytochrome P-450

Metabolism of procarcinogens by cytochrome P-450 enzymes

Benzo(a)pyrene

Polycyclic hydrocarbon associated with lung cancer in smokers

Polycyclic hydrocarbons

Potent carcinogens found in fossil fuels and smoking cigarettes

Vinyl chloride

Chemical associated with angiosarcoma of the liver

Arsenic

Poison associated with lung, bladder, and skin cancers

Bisphenol A (BPA)

Chemical used in polycarbonates and epoxides, potential endocrine disruptor

Ultraviolet radiation

Causes DNA damage and can lead to skin cancers

Ionizing radiation

Carcinogenic electromagnetic and particulate radiations

Bone marrow

Most susceptible organ system to radiation damage

Gastrointestinal effects of radiation

Seen at high doses and may take time to manifest