Human Biochemistry, Volume 2 - Murray R. 1993

Special Topics
Cancer, Oncogenes, Growth Factors
Oncogenic Viruses

Oncogenic Viruses may carry their Genetic information in the form of either DNA or RNA (Table 57.4). In this chapter, we examine several of the most key characteristics of viruses belonging to these two classes.

Polyomavirus and SV40 played a pivotal role in shaping our current understanding of viral oncogenesis. These are small viruses (with a genome of approximately 5 kb) whose circular genomes encode only 5–6 Proteins. Under specific conditions, infection of susceptible Cells with these viruses leads to malignant transformation. It is well established that specific viral proteins drive this process. In the case of SV40, these proteins—frequently referred to as Antigens because they were originally identified using immunological Methods—are known as T and t. The polyomavirus proteins are designated as T, mid-T, and t. The letter T originates from the English word tumor, as the first of these proteins was discovered in tumors. It remains unclear precisely how these proteins induce tumor transformation; however, it is known that T-antigens tightly bind to DNA, which alters Gene Expression patterns. Because these proteins exhibit a cooperative effect, it can be inferred that transformation involves the simultaneous disruption of multiple cellular processes.

Class="center">Table 57.4. Some important oncogenic viruses

Class

Viruses included in this class

DNA viruses

Papovaviruses

Polyomavirus, SV40, papillomavirus

Adenoviruses

Adenovirus types 12, 18, 31

Herpesviruses

Epstein–Barr virus, Herpes simplex virus type 2

Hepadnaviruses

Hepatitis B virus

RNA viruses

Type C Retroviruses

Rodent Sarcoma and leukemia viruses, avian sarcoma and leukemia viruses, human T-Cell leukemia virus types I and II

Type B retroviruses

Mouse mammary tumor virus

Several types of adenoviruses are known to transform specific animal cells. Of particular interest is the Epstein–Barr virus, as it is strongly implicated in Burkitt's lymphoma and nasopharyngeal carcinoma in humans. Cervical cancers may be linked to herpes simplex virus (type 2), while hepatitis B virus is frequently associated with certain forms of Liver Cancer.

Recent findings regarding oncogenes are largely grounded in research on RNA tumor viruses; consequently, our subsequent Structure/133.html">Discussion of oncogenes will frequently draw upon studies focusing specifically on these viruses.



Last update: 06/08/2026

Editorial and Educational Adaptation: This material has been compiled based on the primary/original source text. The project team performed an editorial review, corrected technical inaccuracies, structured sections, and adapted the content for an educational format.

What was processed:

  • elimination of formatting defects (OCR errors, structural breaks, corrupted characters);
  • editorial organization of content;
  • standardization of terminology in accordance with academic sources;
  • verification of factual statements against the original source text.

All mentions of the author, publication year, and origin of the primary text have been preserved in accordance with the source.