Viruses and cancer
Within each cell, in the human body, lies a structure called a nucleus, containing strips of material called DNA. To be precise 47 strips each containing millions of packages of information called genes. These genes are the codes and templates for all the functions of the entire human body. They have evolved over the centuries through countless generations to produce the human form we know today. Over this time our genes have picked up considerable amount of debris. Some of this debris includes strips of genes which actual cause cancer but are kept from mischief by other genes which lie next to them on the same strip of DNA. These good genes, called tumour suppresser genes, were themselves once randomly picked up through the evolutionary pathway but now serve the essential function of guarding the body from the bad cancer genes - we would get cancer without them. Essentially we were born with the tendency to get cancer - its part of us!
It is thought that some of these strips of DNA locked in our DNA actually originate from viruses which have infected us millions of years ago. When they activate they make the cell behave in a way resembling a virus - divide rapidly and spread.
How some viruses can cause cancer
 Damage the DNA. Viruses have the ability to inject strips of DNA into cells and change the way they behave at a genetic level - usually this means making more viruses. With cancer already coded in our DNA guarded by other anti-cancer genes any re-arrangement of the DNA can lead to the start of the malignant process. Along with carcinogens, radiation and sunlight viruses ability to can damage and rearrange the DNA can separating the suppresser genes from the bad genes and cause cancer to start. The most well known of these being:-
The papilloma (wart) virus and cervical cancer, vaginal, vulval or penile cancer.
The Ebstein-barr virus found mainly in Africa called the causing a cancer of the lymph nodes (Burkitt’s Lymphoma).
Hepatitis B and C causing hepatitis and Hepatocellular cancer (liver cancer).
 Damage the immunity. Although, cancer cells have grown originally from our own body there are some differences in their genetic makeup and the proteins they express on their cell surfaces. Only those cells which are able to escape the body’s immune surveillance can progress into a full blown cancer. Everyday we have thousands of cancers developing which are killed off by our immune system. Not surprisingly genetic or acquired conditions which decrease our immunity can contribute to the progression of cancer. The most notable viruses which damage the immune system are:
Acquired immunodeficiency virus (AIDS) causing a range of cancers most notably, Kaposi's sarcoma (a purple skin cancer), lymphoma particularly of the head.
HTLV-1 virus causing a rare type of lymphoma/leukaemia.
Further general information Your doctors and specialist nurses are in an ideal position to give you relevant information on your disease and treatment as they know your individual circumstances. Cancerbackup has a help line (0808 800 1234) and a prize winning video available in English, Italian, Urdu, Bengali, Gujarati & Hindi explaining Radiotherapy & Chemotherapy. Cancernet.co.uk has over 500 pages describing cancer, its management, practical tips and tool which patients, their carers and their doctors have found helpful during the cancer journey.