# Oncogenic Viruses > Oncogenic viruses for FMGE Microbiology: HPV E6 p53 and E7 Rb, HBV-HCC, EBV cancers, HHV-8 Kaposi, HTLV-1 and India's Cervavac vaccine. - Canonical URL: https://prepelephant.com/topics/fmge/microbiology/oncogenic-viruses-fmge - Exam / course: FMGE · Subject: Microbiology - Publisher: PrepElephant (https://prepelephant.com) — Prepared and reviewed by the PrepElephant Academic Review Team - First published: 2026-10-02 - Last updated: 2026-10-02 - How to cite: "Oncogenic Viruses", PrepElephant, https://prepelephant.com/topics/fmge/microbiology/oncogenic-viruses-fmge ## Direct answer Two viral proteins explain most of cervical cancer: HPV 16 and 18, which together account for roughly 70 per cent of cases, encode E6 that binds and degrades the p53 tumour suppressor and E7 that inactivates retinoblastoma protein, jointly freeing the infected cell from its two main brakes on the cell cycle. The wider oncogenic roster runs on the same logic of persistence plus dysregulation: hepatitis B and C driving hepatocellular carcinoma through chronic inflammation; Epstein–Barr virus behind endemic Burkitt lymphoma, nasopharyngeal carcinoma and post-transplant lymphoproliferative disease; human herpesvirus 8 causing Kaposi sarcoma; HTLV-1 causing adult T-cell leukaemia/lymphoma and tropical spastic paraparesis; and Merkel cell polyomavirus in Merkel cell carcinoma. India's counterattack is programme-level: cervical cancer screening by visual inspection with acetic acid in national programme campaigns, and the indigenously manufactured quadrivalent Cervavac vaccine against HPV 6, 11, 16 and 18. ## What you must remember - E6 degrades p53 via ubiquitin-mediated proteolysis; E7 binds and inactivates Rb — the mechanism question the exam asks almost verbatim; HPV 16 is the commonest high-risk type overall, with 16 plus 18 causing about 70 per cent of cervical cancer. - HPV carcinogenesis needs integration of viral DNA into the host genome, switching the cells from productive to transforming infection — persistent infection with high-risk types, not the mere presence of virus, is the cancer precursor. - Vaccine landscape: quadrivalent HPV vaccine (6, 11, 16, 18 — the types behind cervical cancer and genital warts) including the indigenous Indian Cervavac; prophylactic virus-like-particle vaccines work best before sexual debut. - Epstein–Barr virus toolkit: infectious mononucleosis with atypical lymphocytes and a positive Paul–Bunnell heterophile test; the cancer list — endemic (African jaw) Burkitt lymphoma, nasopharyngeal carcinoma, Hodgkin lymphoma subsets and post-transplant lymphoproliferative disease; latent membrane protein 1 is the principal oncogene. - HHV-8 (Kaposi sarcoma-associated herpesvirus): Kaposi sarcoma in HIV and transplant recipients — and endemic Mediterranean Kaposi in the elderly. - HTLV-1: retrovirus transmitted by breast milk, sexual contact and blood, causing adult T-cell leukaemia/lymphoma (clover-leaf nuclei) decades later and HTLV-1-associated myelopathy, the tropical spastic paraparesis of Indian coastal-cluster fame. - Hepatitis B is the vaccine-preventable cancer: chronic carriage drives hepatocellular carcinoma, which is why universal immunisation includes the birth dose. - Screening doctrine in India: visual inspection with acetic acid for cervical cancer in programme rounds, with HPV DNA testing entering as affordable platforms arrive; the birth-dose hepatitis B vaccine is, in effect, an anti-cancer measure. ## Mechanism to clinic: how a virus becomes a cancer Follow one natural history. A persistent high-risk HPV infection of the cervical transformation zone fails to clear; low-grade lesions follow in a minority. In a few, viral DNA integrates, disrupting E2 — the repressor that normally restrains E6 and E7 — and the two oncoproteins run unchecked: E6 dismantles p53 so DNA damage goes unrepaired, while E7 frees E2F from Rb so the cell cycles relentlessly. Accumulated genomic instability yields high-grade dysplasia and, years later, invasive carcinoma. The clinical corollary writes itself: prophylactic virus-like-particle vaccination before exposure prevents the whole cascade, and the screen-detectable preinvasive stage is where visual inspection with acetic acid and colposcopy-directed biopsy intervene. The same template recurs across the table — hepatitis B vaccine preventing hepatocellular carcinoma, and EBV and HHV-8 held in check only where T-cell immunosurveillance holds, which is why immunosuppression unlocks their malignancies. ## Where students slip The E6/E7 swap is the most reliable single mark lost in this chapter: E6 goes with p53 (both contain the digit-friendly mnemonic of six letters or the "6" in p53's 53 — whichever hook holds, do not swap), E7 with Rb. Second, HPV type association: 16 and 18 are the carcinogenic pair, 6 and 11 the wart-causing low-risk pair — a stem about "genital warts, oncogenic type" is testing that 6/11 are low-risk. Third, Burkitt lymphoma geography: the endemic African jaw form is EBV-driven and malaria is the co-factor, while the sporadic Western form is usually EBV-negative — examinees merge them. Fourth, HTLV-1's double identity: the same retrovirus causes both a leukaemia and a spastic paraparesis, and one-half of the pair gets forgotten in the answer. ## Frequently asked questions ### What do the HPV proteins E6 and E7 do? E6 binds and degrades the p53 tumour suppressor through ubiquitin-mediated proteolysis, and E7 inactivates retinoblastoma protein, jointly abolishing the cell's principal cell-cycle and apoptosis brakes. ### Which high-risk HPV types cause most cervical cancer? HPV 16 and 18 together account for roughly 70 per cent of cervical cancers worldwide; types 6 and 11 are low-risk, causing genital warts rather than cancer. ### Which cancers follow Epstein–Barr virus infection? Endemic Burkitt lymphoma (the African jaw tumour, with malaria as co-factor), nasopharyngeal carcinoma, a subset of Hodgkin lymphoma, and post-transplant lymphoproliferative disease in the immunosuppressed. ### What two diseases does HTLV-1 cause? Adult T-cell leukaemia/lymphoma with characteristic clover-leaf nuclei after decades of latency, and HTLV-1-associated myelopathy, also called tropical spastic paraparesis. ### What is Cervavac? India's indigenously developed quadrivalent HPV vaccine covering types 6, 11, 16 and 18 — the vaccine backing national cervical cancer prevention alongside visual-inspection screening.