Learning Objective
By the end of this section, learners should be able to identify microbes that contribute to cancer development, recognize the cancers they are associated with, and understand their clinical significance.
Key Oncogenic Microbes
| Microbe | Associated Cancer(s) | Notes / High-Yield Points |
|---|---|---|
| EBV (Epstein-Barr Virus) | Burkitt lymphoma, Hodgkin lymphoma, nasopharyngeal carcinoma, primary CNS lymphoma (in immunocompromised patients) | High association with endemic Burkitt lymphoma in Africa; latent infection in B cells |
| HBV, HCV | Hepatocellular carcinoma | Chronic viral hepatitis → cirrhosis → HCC |
| HHV-8 (Kaposi sarcoma-associated herpesvirus) | Kaposi sarcoma | Classic, endemic, transplant-associated, or HIV-related forms |
| HPV (types 16, 18) | Cervical carcinoma, penile/anal carcinoma, and head and neck cancers | Viral oncogenes E6 and E7 inactivate p53 and Rb |
| H. pylori | Gastric adenocarcinoma, MALT lymphoma | Chronic gastritis → intestinal metaplasia → cancer |
| HTLV-1 | Adult T-cell leukemia/lymphoma | Endemic in Japan, the Caribbean, and retrovirus. |
| Clonorchis sinensis (liver fluke) | Cholangiocarcinoma | Associated with chronic biliary inflammation |
| Schistosoma haematobium | Squamous cell carcinoma of the bladder | Endemic in parts of Africa and the Middle East; chronic irritation of the bladder wall |
Activity
High-Yield Exam Pearls
- EBV: Burkitt lymphoma is the classic example of a virus-driven cancer.
- HPV: E6/E7 proteins inactivate tumor suppressors p53 and Rb.
- H. pylori: Treating infection can reduce MALT lymphoma risk.
- Chronic viral hepatitis is a major risk factor for hepatocellular carcinoma.
- Schistosomiasis and liver flukes demonstrate parasitically induced cancer through chronic inflammation.
