10.11 Tumor Viruses – Flashcards
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| T/F Virus-induced cancers respond to anti-viral medication. |
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| false |
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| How do you prove that viruses cause human cancer? |
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| 1) strong epidemiologic evience 2) viral elements responsible for cancer are found and expressed in tumor cells 3) virus can cause tumors in-vitro 4) a reasonable mechanism of action has been established |
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| What are Koch's postulates? |
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| 1) MO found in organisms suffering from dz but not in healthy organisms 2) MO isolated and grown 3) cultured MO cause dz in healthy organism 4) MO reisolated from infected organism |
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| What cancer does polyoma virus cause? |
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| merkel's cell |
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| Up to ___% of all human cancers are related to viruses. |
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| 20 |
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| What are the common characteristics of human tumor viruses? |
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| 1) high infection rates, low cancer rates. 2) cancer occurs many years after viral infection 3) virus required for initiation events-allows cells to outlive their usual lifespan. 4) requires other factors (promoters) for cancer |
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| Does HIV cause cancer? |
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| increased risk of cancer with HIV thought to be due to a lack of immune surveillance and not directly due to HIV. |
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| What population is at a higher risk for viral-induced cancers? |
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| immune suppressed |
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| HIV + EBV infection in children can cause what type of neoplasm? |
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| leimyomas and leimyosarcomas |
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| T/F ATLL is usually deadly in 6 months. |
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| False, can be deadly in 6 months but also can be very mild |
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| What percent of pts with ATLL are seropositive for HTLV-1? |
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| 100% |
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| If there is an ATLL endemic area, you can assume that ___% of the population has HTLV-1. |
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| 30% |
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| What percent of HTLV-1 infected individuals develops cancer? |
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| 1-4% |
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| How long does it take after infection with HTLV-1 to get cancer? |
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| 20-30 years later |
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| What types of cells are infected by HTLV-1? |
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| CD4+ |
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| HTLV-1 causes cancer via a transcription factor called... |
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| tax |
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| What type of illness does HHV-8 cause upon primary infection? |
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| infectious mononucleosis-like illness |
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| What virus is associated with primary effusion lymphoma (B cell lymphoma)? |
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| HHV-8 |
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| KS and PEL are more common in patients with HIV or patients who___. |
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| are transplant recipients |
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| What percent of KS patients have HHV8? |
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| 67-80% |
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| How does HHV-8 cause cancer? |
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| vCyc causes cellular proliferation vFLIP, LANA- inhibit cell death vMip-III- causes angiogenesis may cause a robust inflammatory immune response (IFN-gamma, IL-1,IL-6) which leads to angiogenesis |
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| What is the treatment for HHV-8? |
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| HIV anti-retrovirals or reduce immune suppression if possible (intralesional or systemic chemotherapy) |
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| Hep B increases your risk of liver cancer by ___x. |
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| 100 |
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| Hep B DNA is found in what percent of HCC? |
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| 85% (most integrated >75%) |
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| How long does it take to get cancer from Hep B? |
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| more than 30 years |
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| What are the two theories of how hep B causes cancer? |
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| 1) chronic inflammation and cell regeneration 2) x gene |
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| How does the x gene of Hep B cause cancer? |
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| 154 gene is weakly tumorigenic and can activate other genes in the cell such as NFkB, activates ras, JNK, JAK-STAT. Also activates the ERK pathway and binds to CREB |
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| How do you prevent/treat hep B? |
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| prevent with vaccine. Chronic infection has no cure. HCC can be treated with surgery, chemotherapy. |
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| What percent of hep C infection progresses to chronic disease? |
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| 50% |
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| How does hep C cause cancer? |
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| 1) NS3: N terminus has transforming ability 2) NS5A- regulate proliferation or nothing |
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| How do you prevent/treat hep C? |
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| no vaccine, decrease high-risk behavior chronic infection: pegylated interferon-alpha + ribavirin (50%) cure rates HCC: surgery, chemotherapy |
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| What percent of Burkitt's lymphoma is positive in Africa vs. america? |
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| 96% African 30% American |
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| What percent of nasopharyngeal CA is EBV +? |
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| 100% |
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| What percent of hodgkin's disease is EBV+? |
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| 50% |
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| Where is nasopharyngeal ca common and how do you screen for it? |
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| southern china and certain native americans; measure IgA antibodies against EBV |
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| What percent of pediatric versus young adult cases of Hodgkin's are EBV+? |
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| pediatric 70% young adult 15% |
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| T/F EBV related HD is more aggressive. |
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| true |
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| Who is at risk for hodgkin's disease? |
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| increased in third world, hispanic, men, and HIV+ |
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| What percent of immunoblastic lymphoma is EBV+? |
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| 100% |
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| What patient population gets immunoblastic lymphoma? |
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| immunosuppressed (T cells): HIV, BMT, renal transplant |
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| What percent of lymphoproliferative disorder is EBV+? |
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| 100% |
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| When do patients get lymphoproliferative disorder? |
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| post transplant |
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| What's the connection with gastric carcinoma and EBV? |
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| 10% of gastric ca are EBV + and EBV is found in 100% of the cells in the tumor (monoclonal) |
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| What EBV proteins does burkett's lymphoma have? |
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| EBNA-1 |
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| What EBV proteins does Hodgkin's have? |
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| EBNA1 and LMP1 |
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| What EBV proteins does NPC have? |
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| EBNA-1 and LMP-1 |
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| What EBV proteins does Mononucleosis have? |
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| EBNA-1, EBNA-2, LMP-1 |
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| What EBV proteins does PTLD have? |
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| EBNA-1, EBNA-2, LMP1 |
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| How does EBV cause Burkitt's lymphoma? |
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| 75% have c-myc-mu chain translocation |
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| What are EBNAs? |
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| epstein barr nuclear antigens: activators of B cell regulatory proteins |
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| What is LMP-1? |
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| late membrane protein 1 (activates other host genes) |
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| What virus can cause merkel cell carcionma? |
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| polyomavirus |
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| How does polyomavirus cause merkel cell carcinoma? |
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| large T antigen is mutated in cases of merkel's--> likely leads to cancer |
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| Which HPV strains cause plantar and common warts? |
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| 1,2 |
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| Which HPV strains cause condylomata and laryngeal warts? |
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| 6, 11 |
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| Which HPV strains cause anogenital malignancies? |
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| 16,18 |
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| Cervical cancer is the ____ most common malignancy of women world wide. |
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| 2nd |
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| What is the mortality of cervical cancer? |
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| 35% |
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| How do you detect HPV infection? |
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| clinical: genital warts, epithelial defects cellular changes caused by virus via pap DNA hypridization or PCR detection of antibody against HPV (laboratory only) |
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| What percent of cervical and anal cancers have HPV DNA? oral cancers? |
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| 90% 33% |
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| Which oncogenic genes of HPV are expressed in tumors? |
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| E6 and E7 |
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| What increases your risk of HPV/HPV cancer? |
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| increased number of sexual partners, smoking, immune suppression (HIV infection, renal transplant) |
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| What is the funciton of E6? |
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| E6 ubiquinates p53 so that P53 is tagged for destruction |
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| How does E7 protein from HPV cause cancer? |
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| binds and inhibits the function of the tumor suppressor gene Rb |
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| How does HPV repress the E2 gene? |
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| by integrating into the host chromosome at the E2 gene and disrupting it. |
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| T/F E6 and E7 of low risk strains of HPV bind/degrade/suppress p53 and Rb respectively. |
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| FALSE! they do not because they are low risk |
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| What strains of HPV are in the Merck vaccine Gardasil? |
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| 16,18,6,11 |
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| Which HPV strains are in the GSK vaccine Cerverix? |
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| HPV 16, 18 |
