viral factors
Last reviewed 01/2018
A number of DNA and RNA viruses have been associated with neoplasia:
- human papilloma virus:
- thought to be transmitted sexually
- linked to squamous cell carcinoma of the cervix - 90-95% of cases contain HPV, subtypes 16 and 18 being the most common
- cervical carcinoma is particularly associated with an early age at first sexual intercourse and a large number of sexual partners, both supporting the theory of spread of the oncogenic virus
- Epstein-Barr virus:
- linked in a complex way to the production of Burkitt's lymphoma in Africa; possibly related to an abnormal immune response triggered by malaria
- in certain geographic locations, e.g. Southern China and parts of Africa, the virus is invariably associated with the onset of nasopharyngeal carcinoma
- hepatitis B virus: strongly linked to the production of hepatocellular carcinoma, especially in association with aflatoxin from Aspergillus flavus
- human T-cell leukaemia virus:
- associated with the production of leukaemia and lymphoma in certain parts of Japan and the Caribbean
- a T-cell growth factor and receptor seem to be switched on in the same cell, thus causing autocrine proliferation