Question

How do viruses contribute to cancer? (explain)

Answer 1

Viruses are the non-cellular form, consisting of one or more molecules of either DNA or RNA, as genetic material enclosed in a coat of protein. Viruses can reproduce only within living cells and are smaller than prokaryotic cells.

Most of the viruses do not cause cancer. Only some of the viruses has the potential to cause DNA damage in the host cells which inturn increases the chances of cancer.

Ways by which few viruses can cause cancer:

• Viruses upon infection leads to chronic inflammation and this inflammation causes tissue damage, to repair the damage, most of cells divide rapidly and the rapid cell division increases the chances of having an error during DNA replication, ultimately it promotes the development of cancer.
• Some viruses may directly damage the DNA by creating double strand breaks.
• Some viruses may modifies the immune system and weakens the immune response against cancer cells and finally viruses increases the progression of cancer cells.

Viruses that are known to cause the cancer are:

• Human papillomavirus (HPV) mainly the HPV 16 and HPV 18 strain, can cause the various types of cancer like cervical cancer, vaginal cancer, Head and neck cancer etc.
• Hepatitis B virus increases the risk of development of liver cancer.
• Hepatitis C cancer (HCV), also increases the risk of liver cancer.
• Epstein Barr virus (EBV), increases the risk of lymphoma (Burkitt's lymphoma).
• T-Lymphotrophic Virus (HTLV-1), it leads to the development of T cells lymphoma/leukemia.
• Human Herpes Virus 8 (HHV-8), It can cause kaposi's sarcoma.