Carcinogens are substances that induce cancer and can be classified into physical, chemical, and biological agents.
| Carcinogen | Organ affected | |
|---|---|---|
| I. | Coal tar (3, 4 benzpyrene) | Skin, lungs |
| ii. | Cigarette smoke (N-nitrosodimethylamine) | Lungs |
| iii. | Cadmium oxide | Prostate gland |
| iv. | Aflatoxin (a metabolite of Aspergillus flavus, a mould) | Liver |