Pathogens as a cause of cancer
Helicobacter pylori
Estimates place the worldwide risk of cancers from infectious causes at 16.1%.[ 1] Viral infections are risk factors for cervical cancer, 80% of liver cancers, and 15–20% of the other cancers.[ 2] This proportion varies in different regions of the world from a high of 32.7% in Sub-Saharan Africa to 3.3% in Australia and New Zealand.[ 1]
A virus that can cause cancer is called an oncovirus or tumor virus . These include the human papillomavirus , which is associated with cervical carcinoma and nasopharyngeal carcinoma ; Epstein-Barr virus , which is associated with a variety of Epstein-Barr virus-associated lymphoproliferative lymphomas ; Kaposi's sarcoma herpesvirus , which is associated with Kaposi's sarcoma and primary effusion lymphoma ; hepatitis B and hepatitis C viruses which are associated with hepatocellular carcinoma ; human T-cell leukemia virus-1 , which is associated with adult T-cell leukemia/lymphoma ; and bovine leukemia virus , which is associated with breast cancer .[ 3] Bacterial infection may also increase the risk of cancer, as seen in Helicobacter pylori -induced stomach cancer .[ 4] Parasitic infections strongly associated with cancer include Schistosoma haematobium (squamous cell carcinoma of the bladder ) and the liver flukes , Opisthorchis viverrini and Clonorchis sinensis (cholangiocarcinoma ).[ 5]
^ a b de Martel C, Ferlay J, Franceschi S, Vignat J, Bray F, Forman D, Plummer M (June 2012). "Global burden of cancers attributable to infections in 2008: a review and synthetic analysis". The Lancet. Oncology . 13 (6): 607–15. doi :10.1016/S1470-2045(12)70137-7 . PMID 22575588 .
^ De Paoli P, Carbone A (October 2013). "Carcinogenic viruses and solid cancers without sufficient evidence of causal association" . International Journal of Cancer . 133 (7): 1517–29. doi :10.1002/ijc.27995 . PMID 23280523 . S2CID 38402898 .
^ Buehring GC, Sans HM (December 2019). "Breast Cancer Gone Viral? Review of Possible Role of Bovine Leukemia Virus in Breast Cancer, and Related Opportunities for Cancer Prevention" . International Journal of Environmental Research and Public Health . 17 (1): 209. doi :10.3390/ijerph17010209 . PMC 6982050 . PMID 31892207 .
^ Pagano JS, Blaser M, Buendia MA, Damania B, Khalili K, Raab-Traub N, Roizman B (December 2004). "Infectious agents and cancer: criteria for a causal relation". Seminars in Cancer Biology . 14 (6): 453–71. doi :10.1016/j.semcancer.2004.06.009 . PMID 15489139 .
^ Samaras V, Rafailidis PI, Mourtzoukou EG, Peppas G, Falagas ME (June 2010). "Chronic bacterial and parasitic infections and cancer: a review" . Journal of Infection in Developing Countries . 4 (5): 267–81. doi :10.3855/jidc.819 . PMID 20539059 .