Globally, more than 15% of human cancer cases occurring in 2008 could be ascribed to infectious agents classified as carcinogenic according to the international agency for research on cancer iarc. To date, seven viruses ebv, kshv, highrisk hpv, mcpv, hbv, hcv and htlv1 have been consistently linked to different types of human cancer, and infections are estimated to. This indicates that the virus is no stranger to our immune systems. The relationship of cervical cancer and sexual behavior was suspected for more than 100 years and was established by epidemiologic studies in the 1960s. Viruses may contribute to the development of human tumors by different mechanisms. Viruses and human tumours bacteriophage subviral agents isolation of virus diagnosis treatment and prevention of virus infections sub microscopic entity consisting of a single nucleic acid surrounded by a protein coat and capable of replication only within the living cells. A number of different viruses have been associated. Read about cancer signs, stages, cells, symptoms, and types. Chienjen chen, wanlun hsu, hwaii yang, meihsuan lee, huichi chen, yin chu chien et al.
Three of these cancers kaposi sarcoma, non hodgkin lymphoma, and cervical cancer are considered aidsdeining cancers. Although many viruses can cause various tumors in animals, only seven of them are associated with human cancers and are currently considered oncogenic viruses. T cells, also support the link between these human viruses and cancer. Human oncogenic viruses and their associated tumors. Cancer causing viruses and the role of laboratory medicine scielo. When the dna or rna affects the host cells genes, it can push the cell toward becoming cancer. It is usually spread through vaginal, oral, or anal sex. To date, seven viruses ebv, kshv, highrisk hpv, mcpv, hbv, hcv and htlv1 have been consistently linked to different types of human cancer. The eight known human tumour viruses contribute to nearly 1015% of the cancers worldwide. About a fifth of all human cancers worldwide are caused by infectious agents. Upon entry, the virus uses components of the host cell to complete its life cycle. Several factors increase the risk of developing cancers such as smoking for lung cancer or sun exposure for melanoma. Human papillomavirus hpv human papillomavirus, or hpv, is the most common sexually transmitted infection sti in the united states.
With the letters rna removed, it now refers to any virus with a dna or rna genome causing cancer and is synonymous with tumor virus or cancer virus. Other factors may increase the chance of cancer including immune system complications, cell mutations, exposure to cancer causing agents and hereditary susceptibility. Some viruses can cause or contribute to the development of cancer. Human t lymphotrophic virus type 1 and hepatitis c viruses are the two rna viruses that contribute to human cancers.
Table 431association of viruses with human cancersa. Studies evaluating markers of a bodys weakened immune system, or immunosuppression, such as decreased cd4 t cells, also support the link between these human viruses and cancer. Pdf the first human tumor virus was discovered in the middle of the last century by anthony epstein, bert achong and yvonne barr in african. Breast cancer is currently the most common neoplasm diagnosed in women globally. The human tumour viruses induce malignancies after a prolonged latency and in conjunction with other environmental and host factors. After a preliminary chapter about the general biological characteristics of. Scribd is the worlds largest social reading and publishing site. The first human tumor virus was discovered in the middle of the last century by anthony epstein, bert achong and yvonne barr in african pediatric patients with burkitts lymphoma. In general, each type of virus tends to infect only a certain type of cell in the body. Close study of viruses and human cancer has led to optimism for the development of new strategies for the prevention of the preceding infection that can lead to carcinogenesis. Chapters are written by internationally recognized experts, and all are generously illustrated with tables, diagrams, and photographic images. It is estimated that viral infections contribute to 1520% of all human cancers.
Vaccines have been developed against some cancer viruses including hepatitis b and human papillomaviruses hpv 16 and 18. Researchers know that there are several viruses that can lead to cancer. In recent years, great leaps in genomic sciences have allowed researchers to detect viruses living in and on the human bodycollectively called the human virome. Highthroughput sequencingbased investigation of viruses. Viruses and human cancer from basic science to clinical prevention is designed to meet this need by providing an advanced overview on the basic and clinical aspects of oncogenic viruses and the human cancers that they cause. The first question was whether there was any evidence of human exposure, and, indeed, people do have antibodies to these cancercausing chicken viruses in their bloodstream. Currently, acknowledged human cancer viruses include epsteinbarr virus, hepatitis b virus, hepatitis c virus, highrisk human papilloma viruses, human tcell lymphotropic virus type 1 and kaposis sarcomaassociated herpesvirus. Human papillomavirus 175 11 human papillomavirus hpv is the most common sexually transmitted infection in the united states. Papillomaviruses are dna viruses that exhibit species specificity and induce hyperplastic epithelial lesions as a result of infection. The aim of this study was to determine the presence of hpv in patients with breast cancer and its possible association with. Epsteinbarr virus, hepatitis b virus, human papillomavirus, human tcell lymphotropic virus, hepatitis c virus, kaposis sarcoma herpesvirus, and merkel cell polyomavirus. Oncogenic viruses virology online microbiology notes.
This excludes viruses and cancer sites for which evidence of carcinogenicity is weaker. Concern has been raised about the potential infectivity of cancercausing farm animal viruses for decades. The viruses now known or suspected of being linked to cancer in humans include human papilloma viruses, the epsteinbarr virus, the hepatitis b and c viruses, the human herpes. Inform yourself about the role viruses play in contributing to cancer. Recent genomic explorations of human samples have revealed dozens of previously unrecognized viruses resident in our gut, lung, skin, and blood. The new england journal of medicine 312 n engl j med 360. This book provides an uptodate overview of the 6 major viruses that cause human cancers hpv, hbv, hcv, ebv. In addition to the above viruses and cancers, there also exist a number of other cancers that may have an infectious etiology. They include human papillomaviruses hpvs, epsteinbarr virus ebv, human herpesvirus 8, hepatitis b virus, hepatitis c virus, and two human retroviruses plus. Some viruses do this by inserting their own dna or rna into that of the host cell. There is a growing body of evidence to suggest that human papillomavirus hpv infection may play a key role in invasiveness of breast cancer. As obligatory intracellular parasites, viruses encode proteins that reprogram host.
The viruses that have been strongly associated with human cancers are listed in table 431. This term originated from studies of acutely transforming retroviruses in the 195060s, when the term oncornaviruses was used to denote their rna virus origin. Tumor viruses and human malignancy about 20% of human cancerresults from tumor virus infection study of rna and dna tumor viruses has revolutionized modern concept of cancer development cancer is a disease of genes study of cancer using molecular biology and tumor viruses as tools concept of cancer as a transferable infectious disease. The first identification of a tumorcausing virus, rous sarcoma virus, occurred almost 100 years ago, but it was not until the 1970s that the genetic basis for oncogenesis by this and other acutely. From basic information about cancer and its causes to indepth information on specific cancer types including risk factors, early detection, diagnosis, and treatment options youll find it here. In 12% of cancers, seven different viruses have been causally linked to human oncogenesis. Infection by viruses is the second leading cause of cancers. Viruses are the causes of approximately 25% of human cancers. Important human cancer viruses human tcell leukemia virus is a member of the retrovirus family rna genome epsteinbarr virus and kaposis sarcoma virus are members of the herpesvirus family dna genome human papilloma virus is a member of the papillomavirusfamily dna genome.
Epsteinbarr virus, human papilloma virus, hepatitis b virus, and human herpes virus8 are the four dna viruses that are capable of causing the development of human cancers. The genome of htlv1 has a characteristic retroviral organization, i. Whenever cells divide, there is a risk that a genetic mutation will take place. Since then, seven human viruses have been found to cause 1015% of human cancers worldwide. Multiple treatments are required and in the case of hpv 16 and 18, the vaccine does not protect against other forms of the virus. As an example, skin cancer is believed to be greatly increased by exposure to ultraviolet uv radiation from the sun. Radiation can also cause genetic damage that can lead to cancer. Research on oncogenic viruses and related human cancers has advanced rapidly in the past decade. Five viruses are being added to the report on carcinogens. A cancer treatment in which high energy beams are used to kill cancer cells. Due to their importance in carcinogenesis, there is a desperate need for a book that discusses these viruses. About 80 percent of women will get at least one type of hpv at some point in their lifetime.
To date, seven viruses ebv, kshv, highrisk hpv, mcpv, hbv, hcv and htlv1 have been consistently linked to different types of human cancer, and infections are estimated to account for up to 20% of all. Accordingly, hormoneresponsive viruses have become major suspects as etiological agents for human breast cancer. National institute of environmental health sciences nihhhs cancercausing viruses. The year 2011 marks the centenary of francis peyton rouss landmark experiments on an avian cancer virus. There is consequently a need for a comprehensive, uptodate monograph that offers broad and integrated knowledge. For example, the human papillomavirus hpv can cause cervical and several other cancers. The first identification of a tumorcausing virus, rous sarcoma virus, occurred. Viruses account for about 20% of total human cancer cases. Principles of transformation and pathogenesis by john nicholas 2008 english pdf.
Viruses and human cancer presents a general overview of all viral infections now known to be linked with human cancers. Some cancer registries exclude nonmelanoma skin cancers, or attribute deaths to hiv rather than. Printer friendly version pdf icon pdf common human coronaviruses, including types 229e, nl63, oc43, and hku1, usually cause mild to moderate upperrespiratory tract illnesses, like the common cold. The human cancers associated with viral infection are summarized in table 2. A causal role for these viruses in human malignancies remains to be fully addressed. These five viruses are more likely to lead to cancer in people that. Unlike other viruses, such as influenza viruses, that cause an acute infection, oncogenic viruses often cause longterm, persistent infections. Advancements in research on virusrelated cancers offer a. Viruses and human cancer from basic science to clinical. It will also be of great value to practicing physicians, residents and clinical fellows in these specialties. Close study of viruses and human cancer has led to optimism for the development of new strategies for the prevention of the preceding infection that can lead to. Some viruses lead to inflammation or tissue damage that triggers increased cell divisionwhich leads to a greater chance that mutations will take place, eventually leading to cancer. Viruses associated with human cancer sciencedirect.
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