Cancers related to viral agents that have a direct role in carcinogenesis: pathological and diagnostic techniques

Abstract

The International Agency for Research on Cancer has recently reassessed the carcinogenicity of the biological agents classified as ‘carcinogenic to humans’. Among the biological agents having a direct role in carcinogenesis, Epstein-Barr virus, Kaposi's sarcoma-associated herpes virus and human papillomavirus contribute to a variety of malignancies worldwide in humans including nasopharyngeal carcinoma, several types of lymphomas, genital tract carcinomas and Kaposi's sarcoma. The authors review the current knowledge on cancers that have been attributed to Epstein-Barr virus, Kaposi's sarcoma-associated herpes virus and human papillomavirus looking at the pathological classification of these cancers and description of the implicated viruses, highlighting a wide range of pathological and virological diagnostic techniques. This review also focuses on the new oncological scenario ahead, once strategies against carcinogenic infectious agents are found to be effective.

Immunosurveillance by Antiangiogenesis: Tumor Growth Arrest by T Cell–Derived Thrombospondin-1

“…The polarization of these cells towards a pro-angiogenic, pro-tumor state appears to be enhanced by chronic viral infection and sustained inflammation. For example, the inflammatory state created by hepatitis B or C infection is estimated to account for 80% of hepatocellular carcinomas, and 70% of cervical cancers are attributed to human papilloma virus infection (17, 24). Chronic infection perpetuates the presence of T regulatory cells, which express high levels of pro-angiogenic VEGF (25).…”

Carcinogenic viruses and solid cancers without sufficient evidence of causal association

“…Epidemiological and biological studies have now conclusively proved that infectious agents are among the main causes of cancer worldwide. At least six different viruses have been linked to the development of several types of human cancers . HPV, EBV and KSHV/HHV8 play a direct role in carcinogenesis, encoding oncoproteins which are able to promote cellular transformation by altering the regulation of cell cycle, apoptosis and other cellular pathways.…”

“…Supporting Information Table S1 lists the viruses classified as carcinogenic to humans and cancers for which there is sufficient evidence in humans . EBV causes several types of cancer, including nasopharyngeal carcinoma and Burkitt's lymphoma in children in Africa . New evidence points to a role for EBV in lymphoepithelioma‐like gastric carcinoma …”

The Impact of HPV as an Etiological Factor in Gynecological and Oropharyngeal Cancer

“…1 Approximately 15 HPV types are considered high risk, [2][3][4][5][6] and infection with these agents has been associated with induction of carcinoma of the cervix, vulva, vagina, penis, anus, and oropharynx (tongue base and tonsil). 1,7 The high-risk HPV types (HPV- 16, -18, -31, -33, -35, -45, -52, and -58) are associated with nearly all cases of cervical cancer in the world. 1 HPV 16 and 18 are the high-risk subtypes responsible for more than 70% of HPV-infection-related cancer.…”

“…1,7 The high-risk HPV types (HPV- 16, -18, -31, -33, -35, -45, -52, and -58) are associated with nearly all cases of cervical cancer in the world. 1 HPV 16 and 18 are the high-risk subtypes responsible for more than 70% of HPV-infection-related cancer. 7 HPV-associated cancers in the oropharynx and anogenital tract are typically squamous cell carcinomas (SCCs).…”