Oncogenic viruses

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From the point of view of molecular biology of cancer is not so diverse disease. The same gene can be activated in any tissue. The nature of the tumor is not dependent on the type of oncogene. He is determined only by the type of tissue. If the virus infects the genome of cells develops leukemia, when activated oncogene in the cells of the muscles or connective tissue sarcoma occurs, the transformation of epithelial cells entails cancer.
Until recently, there was a lot of doubt as to whether viruses cause tumors only in animals or there are opujolevidnami human viruses. Gradually accumulated a lot of indirect evidence of the participation of viruses in oncological diseases. So, liver cancer often develops in people who have had infectious hepatitis (a disease Hungary). Epidemiological and immunological researches have shown, that almost 90% of patients with primary liver cancer have antibodies to the virus In or contain particles in tumor cells.
In 1958, English surgeon, Doctor of Berkyt described particularly common in Equatorial Africa malignant tumor of the face of earth, mainly children. The main part of the tumor mass was lymphoid cells, so the disease is called lymphoma Berkuta. Later it was shown that the most likely cause of it is one of the viruses of herpes group, called the virus Epstein-Barr after the English virologists, who discovered it. The virus this relatively widely distributed, and lymphoma Berkuta is a rare condition (in Africa is logged 5-10 thousand cases per year). Later it turned out that with the same virus may be linked to cancer of the nasopharynx, which is particularly common in southern Asia, southern China, Northern Africa and the Inuit. In addition, the virus Epstein-Barr considered to be the main cause of infectious mononucleosis, which marked the expansion of the lymphoid tissue, the transient increase in lymph nodes and increase the number of immature lymphocytes in the blood.
In recent years, M. Epshtein with employees received two versions of the vaccine against the virus Epstein - Barr. One option is artificial bubbles of lipoprotein-liposomes stuffed with glycoprotein outer membranes of the virus, the other - they themselves membrane virus infected human cells. Both vaccines linked antibodies to the virus and warned the monkeys development of virus-induced leukemia.
Most, if not all women with cancer of the cervix and vulva, find papillomatosis virus or antibodies to DNA of some viruses in this family. The introduction of the viral DNA into the genome of cells may be the first step toward malignancy, so papillomatosis the virus, especially its types 16 and 18, is regarded as a potential oncogenes. These viruses contained within the cells of long-transplantable culture HeLa. If we add in normal cells, and those soon transformed into the tumor. Interestingly, in the transplantation of such netransformovany cells of mice-nudam tumor recipients do not develop; under the influence of unknown antagonists viral genome is eliminated.
Unlike viral oncogenes animals, leading to the rapid development of tumors, viral infections of human cells is accompanied by a long, sometimes many years of peaceful coexistence of these cells in the body. Changes encoded by the viral DNA is transferred in cell generations, and required some additional incentives to cause a tumor. So oncogenic viruses person believe latent or "bomb with a delayed fuse".