Hepatitis C is an RNA virus that infects 3% of the world's population. Hepatitis C can be acute or chronic. In the case of chronic infection it causes cirrhosis which can then lead to primary hepatocellular carcinoma in some individuals. 



Hepatitis C Virus 
 

Hepatitis B virus is a DNA virus and Hepatitis C virus has a very high mutation rate with 11 genotypes and many subtypes which can easily escape  the immune system recognition. It can cause cirrhosis and liver failure if it lasts for more than three months. Hepatitis C can lead to hepatocellular carcinoma and in some cases death. Treatments for hepatitis-induced liver disease can be surgical such as tumor incision or liver transplant. Nonsurgical treatments include“percutaneous ethanol injection, transarterial embolization, radiofrequency ablation, chemotherapy, and radiotherapy” (John 1). 
Treatment choices are made based on liver function and cancer prognosis. 


Interferons are used to decrease viral replication and thus eliminate or reduce liver complications. Medications such as lamivudine, adefovir, entecavir, and telbivudine target viral replication and have been  found to be effective. 
With transplantation, oral medications prevent Hepatitis B but not Hepatitis C recurrence. 


Hepatitis B virus 


EBV and HHV-8 are both herpes viruses which have large double stranded DNA. Nearly 95% of all adultes are seropositive. These viruses encode enzymes in DNA replication, repair and nucleotide biosynthesis. 

EBV is associated with B and T cell lymphoma, Hodgkin’s disease, post-transplant lymphoproliferative disease, leiomyosarcomas, and nasopharyngeal carcinomas. Research has shown individuals with immunodeficiency are more likely to develop such illness and thus immunosurveillance plays an important role in the prognosis of such conditions. 

Biopsies of Kaposi Sarcoma contained HHV-8 DNA,which suggested the cancer was caused by HHV-8. Kaposi sarcoma was a rare type of cancer before the AIDS epidemic but AIDS increased this kind of cancer. This underscores the role of immunosuppression in the development of Kaposi sarcoma. This suggests that immunotherapy  and targeted therapy are the best ways to eradicate this type of cancer.


Epstein-Barr Virus (EBV) and Human Herpesvirus 8 (HHV-8) 


Human Papillomavirus (HPV) is another virus that causes cancer in humans. Most HPV-induced diseases are benign such as warts but those caused by high risk strains of HPV such as 16 and 18 causes cervical and penile cancer. Other HPV-related cancers are head and neck cancer and some skin cancer. Immunosuppressed individuals are at particularly high risk of HPV-induced cancers.


Human Papillomavirus (HPV) 


HTLV-1 is a single-stranded RNA virus that causes adult T cell leukemia. Even Though HTLV-1 infects between 12 to 25 million individuals, only 5% are symptomatic. 
Route of transmission; blood transfusions, sexual contact, and during parturition. 
Although it is not well understood how HTLV-1 causes adult T cell leukemia, researchers have seen a strong link with the specific CD8 T cells and the growth of T cell leukemia.


Human T lymphotropic virus type-1 (HTLV-)

- Hepatitis C Virus 
- Hepatitis B virus 
- Epstein-Barr Virus (EBV) and Human Herpesvirus 8 (HHV-8) 
- Human papillomavirus (HPV) 
- Human T lymphotropic virus type-1 (HTLV-) 


Northwestern University

15% of all human cancers worldwide are caused by viruses. The viruses that cause cancer contain either single-stranded RNA or double-stranded DNA genomes.  RNA viruses include Human T lymphotropic Virus type 1 and Hepatitis C and DNA viruses are HPV, Human Herpesvirus-8, Epstein-Barr Virus, Hepatitis B Virus. All of these viruses are blood-borne pathogens and are transmitted via blood transfusions, sexual contact, and during parturition. Oncogenesis driven by viral proteins are easier to treat through targeted therapy and immunotherapy because the presence of viral gene products differentiates between normal cells and cancerous cells. Vaccination is recommended for prophylaxis and treatment of this kind of cancer in order to strengthen the immune system, stop viral replication, and inactivate the virus. Although virus-mediated tumorigenesis is slow, other factors can play an important role in cancer progression such as genetic factors, environmental factors, and immunosuppression. Below is the infectious viruses that lead  to carcinogenesis in exposed individuals:



Virus Driven Cancers: The Match for Immunotherapy and Targeted Therapy 



Viruses that cause cancer 

The advantage of virus driven tumorigenesis over other types of cancers is the viral proteins present in this type of cancers acts as a “revealer.” Targeted therapy and immunotherapy can be utilized over traditional treatments such as chemotherapy and radiation which are toxic to both healthy and tumor cells, in order to destroy tumor cells specifically. 



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