Learning Objective
By the end of this section, learners should be able to identify major chemical, physical, and biological carcinogens, recognize their routes of exposure, target organs, and the types of cancers they induce.
Key Carcinogens, Exposure, Target Organs, and Associated Cancers
| Carcinogen | Exposure / Source | Target Organ | Associated Neoplasm |
|---|---|---|---|
| Aflatoxins (Aspergillus) | Stored grains and nuts | Liver | Hepatocellular carcinoma |
| Alkylating agents | Oncologic chemotherapy | Blood | Leukemia / lymphoma |
| Aromatic amines (e.g., benzidine, 2-naphthylamine) | Textile industry dyes, tobacco smoke | Bladder | Transitional cell carcinoma |
| Arsenic | Herbicides, metal smelting, wood preservation | Liver | Hepatic angiosarcoma |
| Lung | Lung cancer | ||
| Skin | Squamous cell carcinoma | ||
| Asbestos | Old roofing materials, shipyard work | Lung | Bronchogenic carcinoma > Mesothelioma |
| Tobacco smoke | Smoking | Bladder | Transitional cell carcinoma |
| Cervix | Squamous cell carcinoma | ||
| Esophagus | Squamous cell carcinoma / adenocarcinoma | ||
| Kidney | Renal cell carcinoma | ||
| Larynx | Squamous cell carcinoma | ||
| Lung | Squamous cell carcinoma / small cell carcinoma | ||
| Oropharynx | Squamous cell carcinoma | ||
| Pancreas | Pancreatic adenocarcinoma | ||
| Ethanol | Alcohol consumption | Esophagus | Squamous cell carcinoma |
| Liver | Hepatocellular carcinoma | ||
| Breast | Breast cancer | ||
| Ionizing radiation | Medical/environmental exposure | Blood | Leukemia |
| Thyroid | Papillary thyroid carcinoma | ||
| Nickel, chromium, beryllium, silica | Occupational exposure | Lung | Lung cancer |
| Nitrosamines | Smoked foods | Stomach | Gastric cancer (intestinal type) |
| Radon | Uranium decay, accumulates in basements | Lung | Lung cancer (2nd leading cause after tobacco) |
| Vinyl chloride | PVC pipe manufacturing | Liver | Hepatic angiosarcoma |
Activity
High-Yield Exam Pearls
- Aflatoxin → Hepatocellular carcinoma; risk increased with Hepatitis B virus co-infection.
- Arsenic → Skin, lung, liver cancers; often in contaminated drinking water.
- Asbestos → Mesothelioma, long latency, synergistic with smoking for lung cancer.
- Tobacco smoke → Multi-organ carcinogen; the single largest preventable cause of cancer.
- Vinyl chloride → Rare liver cancer: hepatic angiosarcoma.
- Radon → Second leading cause of lung cancer after smoking.
