1. Virus and Cancer

2. Viruses are usually not complete carcinogens in human cancers
Tumor viruses establish chronic infections in humans
Cancer is an accidental side of viral replication strategy

3. Two classes of genes
Oncogenes: These are stimulatory for growth, cause cancer when hyperactive.
Tumor-suppressor genes: genes that inhibit cell growth and cause cancer when turned off.

4. How do Virus get involved?
Virus can either
carry a copy of one of these genes or can alter expression of the cell’s copy.

5. What is a virus? Non-living particle
Consisting of proteins and nucleic acid, either DNA or RNA at its core
A Virus

6. RNA Can not replicate on its own, uses host machinery to replicate.
Entrance is gained through receptors on the cells.
Once inside, viral RNA is reverse read to make a segment of DNA
Reverse Transcriptase

7. Viral Replication 4 steps 1. Attachment and entrance
2. Synthesis of proteins
3. Assembly of new virus
4. Release of new virus particles (lytic or lysis)

8. Virus to Cancer DNA Tumor viruses 2 life styles
A permissive cell: all viral parts are replicated
Lysis and death of cell
A non-permissive cell: DNA integrated into the cell chromosome randomly.
Only parts are expressed
No progeny released.

9. How the virus works in two disorders
Hepatitus C
Cervical Cancer

10. P53 (tumor suppressor) P53 gene P53 gene P53 gene Hepatitis C
Papilloma
P53
P53
P53
A similar thing happens to p53 protein in hepatitis C-infected cells and p53 is bound so that it becomes inactive. Again, lack of p53 results in loss of growth control. In papilloma-infected cells, things happen a little differently. In this case the virus makes a protease that destroys p53 protein.
Thus, our knowledge of how RNA tumor viruses cause tumors led to the discovery of viral oncogenes. This led to the discovery of cellular oncogenes which in turn led to anti-oncogenes. The discovery of anti-oncogenes showed how DNA tumor viruses cause tumors.
Papilloma proteolysis
P53
DNA
Stops replication
replication
replication

11. Hepatitus C
Viral proteins interact with p53 and lead to cell proliferation and prevents apoptosis
Transfers by blood
Liver damage, such as cirrhosis, or scarring of the liver
Liver failure
Need for a liver transplant
Liver cancer
Death

12. Human Papillomavirus Malignant carcinomas DNA Virus 8 kilobases long
>100 types of HPV
Cause warts – benign
Malignant carcinomas
epidermodysplasia verruciformis
Autosomal recessive mutation
leads to abnormal uncontrolled virus replication.
Penile, uterine, cervical, canal carcinomas

13. HPV

14. Cervical Cancer New cases 2012 US: 12,170 Deaths: 4,220
average age at death 57 yrs
Incidence rate:
8.1 per 100,000 women
Hispanics 11.8 per 100,000 women
Lifetime Risk for women born today- 1 in 147.
All statistics from the National Cancer Institute, Surveillance Epidemiology and End Results.
A small but significant proportion of human cancers are caused by mechanisms
that involve viruses, bacteria or parasites (15%).

15. Symptoms

16. Diagnosis

17. Treatment Precancerous lesions Cryosurgery (freezing)
Leep- loop electrosurgical excision procedure.
Laser vaporization
Cancerous tissue
Surgery
Radiation
Chemotherapy
Surgery is radical hysterectomy

18. New Treatment: Guardacil
From the U of Rochester
HPV Vaccine
Protects against 4 types of HPV
“2 types of HPV that cause about 75% of cervical cancer cases, and 2 more types that cause 90% of genital warts cases. In boys and young men ages 9 to 26, GARDASIL helps protect against 90% of genital warts cases”
(Guardacil.com)

19. How a vaccine works

20. Cutting edge research Penn Medicine, University of Pennsylvania
Immunotherapy program
Personalizing approach that boosts the bodies own immune system to attach tumors.
Using the patients own tumor proteins in a vaccine.
Using the patients frozen turmor protein is extracted (lysate). This is injected into the patient every 2 weeks, 5 times total.
A CT scan assess the tumor.

21. Conclusion
Virus can show up in the DNA of a host, damaging the cell cycle, causing uncontrolled growth of a cell.
Virus that are carcinogenic are passed in body fluids.
Be safe.
Consider a vaccine to help prevent cervical cancer.
Safe sex, don’t share needles,

22. References
Hunt, R Microbiology and Immunology on-line, University of South Carolina School of Medicine. Howlader N, Noone AM, Krapcho M, Neyman N, Aminou R, Altekruse SF, Kosary CL, Ruhl J, Tatalovich Z, Cho H, Mariotto A, Eisner MP, Lewis DR, Chen HS, Feuer EJ, Cronin KA (eds). SEER Cancer Statistics Review, (Vintage 2009 Populations), National Cancer Institute. Bethesda, MD National cancer institute. National institute of health. ge2 Ovarian Research. Penn Medicine, University of Pennsylvania. Available at