1 / 9

Tumor viruses

Tumor viruses. Tumor viruses. Viruses can cause bening or malignant tumors in many species of animals A few viruses are associated with human tumors. Malignant transformation of cells. Altered morphology Altered growth control Altered cellular properties Altered biochemical properties

vina
Download Presentation

Tumor viruses

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Tumor viruses

  2. Tumor viruses • Viruses can cause bening or malignant tumors in many species of animals • A few viruses are associated with human tumors

  3. Malignant transformation of cells • Altered morphology • Altered growth control • Altered cellular properties • Altered biochemical properties can be induced by tumor viruses

  4. Tumorigenesis • Provirus:thegenesenterthecellbyinfectionbytumorvirus • Oncogene: • Viralor • alreadypresent in thecell cellularoncogenes(c-onc) areactivatedbyvirusestooverproducethegrowthfactors • Tumorsupressor gene (p53):inactivation of this gene • Micro-RNA genes

  5. Human Tumor viruses • RNA viruses: • Human T-cell lymphotropic virus(HTLV-I): • Adult acute T-cell lymphocytic leukemia (ATLL) • No viral oncogene (different from animal tumor retroviruses) • Tax and rex regulatory genes (complex retrovirus) • Incubation period is long

  6. Tumor viruses • Humanpapillomavirus: • E6 and E7 genes • Encodeproteinsthatinterferewith p53 and Rb(retinoblastom) tumorsupressorgenes (inactivation) • Mostlythe HPV(especiallyhighlyoncogenictypes 16 and 18) is integratedintocellular DNA

  7. Tumor viruses • EBV: • Induces B cell proliferation • Activation of a cellular oncogene • Burkitt lymphoma: c-myc oncogene in chromosome 8 is translocated to14 chromosome where large amounts of c-myc RNA are synthesized.

  8. Tumor viruses • HBV: • Primer hepatocellular carcinoma:integration may activate an oncogen • HCV: • Chronic infection • HHV-8: • ?

  9. Animal tumor viuses • DNA Viruses: • SV40 • Adenovirus • Poxviruse • RNA viruses • Retroviruses: viral oncogene(highly oncogenic) No evidence that they cause tumors in humans

More Related