3. Which of the following is not an oncovirus?
a. Hepatitis B Virus (HBV)
b. Hepatitis C Virus (HCV)
c. Epstein Barr Virus (EBV)
d. Dengue Virus (DENV)

The correct answer is: d. Dengue Virus (DENV) is not an oncovirus. The other three viruses (HBV, HCV, EBV) are well-established human oncogenic (cancer‑causing) viruses.​​

Introduction

Oncoviruses are viruses that have a proven association with the development of human cancers, typically by causing chronic infection, persistent inflammation, or direct alteration of host cell genes that regulate growth and apoptosis. In competitive exams, questions like “Which of the following is not an oncovirus?” test both conceptual clarity of viral oncology and recall of specific virus–cancer links.​

Question and correct option

Question:
3. Which of the following is not an oncovirus?
a. Hepatitis B Virus (HBV)
b. Hepatitis C Virus (HCV)
c. Epstein Barr Virus (EBV)
d. Dengue Virus (DENV)

Correct option: d. Dengue Virus (DENV)

HBV, HCV and EBV are recognized among the main human cancer‑associated viruses, whereas Dengue virus is not classified as an oncogenic virus.​

Concept of oncovirus

Oncoviruses (oncogenic viruses) are those that increase the risk of specific cancers in infected individuals, usually demonstrated by epidemiological associations and mechanistic studies. Major human oncoviruses include hepatitis B virus, hepatitis C virus, Epstein–Barr virus, human papillomavirus, Kaposi’s sarcoma–associated herpesvirus, human T‑lymphotropic virus and Merkel cell polyomavirus.​

Key mechanisms by which oncoviruses promote cancer include:

• Integration or persistence of viral genome leading to dysregulation of host oncogenes and tumor suppressor genes.​

• Chronic inflammation and cirrhosis in organs like the liver, creating a microenvironment favoring malignant transformation.​

Option a: Hepatitis B Virus (HBV)

Hepatitis B virus is a DNA virus that infects hepatocytes and can cause acute and chronic hepatitis. Chronic HBV infection is strongly associated with the development of hepatocellular carcinoma (HCC), making HBV one of the most important human oncoviruses.​

Mechanistic highlights:

• Persistent HBV infection causes chronic liver inflammation and cirrhosis, both major risk factors for HCC.​

• HBV DNA can integrate into the host hepatocyte genome and alter expression of growth‑regulatory genes, promoting malignant transformation.​

Therefore, HBV is an oncovirus, so it is not the correct answer to “which is not an oncovirus.”

Option b: Hepatitis C Virus (HCV)

Hepatitis C virus is an RNA virus that also preferentially infects liver cells and leads to chronic hepatitis in a large proportion of infected individuals. HCV is recognized as a carcinogenic agent and is a major cause of hepatocellular carcinoma worldwide.​

Important points:

• Long‑standing HCV infection produces chronic necro‑inflammatory liver damage, fibrosis, and eventual cirrhosis, which greatly increase HCC risk.​

• Viral proteins and the inflammatory milieu can induce oxidative stress, genomic instability and disruption of cell‑cycle control, facilitating oncogenesis.​

Thus, HCV is clearly an oncovirus, and it cannot be the “not an oncovirus” option in this MCQ.

Option c: Epstein–Barr Virus (EBV)

Epstein–Barr virus (EBV), a human herpesvirus (HHV‑4), is one of the earliest identified human oncogenic viruses. EBV establishes lifelong latent infection in B lymphocytes and some epithelial cells and is associated with several malignancies.​

Key cancer associations:

• Burkitt lymphoma, Hodgkin lymphoma and post‑transplant lymphoproliferative disorders.​

• Nasopharyngeal carcinoma and a subset of gastric (stomach) cancers, leading to its classification as a type I carcinogen.​

Oncogenic mechanisms involve latent EBV proteins and non‑coding RNAs that modulate host signaling pathways, inhibit apoptosis, alter epigenetic patterns and support uncontrolled proliferation. Therefore, EBV is definitively an oncovirus, not the correct “non‑oncovirus” choice.​

Option d: Dengue Virus (DENV) – the non‑oncovirus

Dengue virus (DENV) is a mosquito‑borne flavivirus transmitted mainly by Aedes aegypti and Aedes albopictus mosquitoes and is responsible for dengue fever and dengue hemorrhagic fever. Although dengue can cause severe acute illness with vascular leakage and bleeding, it is not implicated in human cancer causation and is not listed among recognized oncoviruses.​

Reasons DENV is not considered an oncovirus:

• Dengue infection is typically acute and self‑limited, without the kind of chronic persistent infection or tissue‑level inflammation characteristic of HBV and HCV that predispose to cancer.​

• There is no established epidemiological or mechanistic link between dengue and specific human malignancies comparable to the links seen with HBV, HCV or EBV.​

Hence, Dengue virus (DENV) is not an oncovirus, making option d the correct answer.

Summary table for quick revision

This analysis directly answers the MCQ “Which of the following is not an oncovirus – HBV, HCV, EBV, DENV?” and explains why Dengue virus (DENV) is the only non‑oncogenic option among the four.