Here we've listed four main ways in which it is thought a virus may cause cancer...

1) In order to incorporate its DNA into a host cell’s strand, a virus “plays” with the DNA in a cell. There is a chance the host DNA may become altered while it is being cut and pasted back together. If the DNA is damaged during this process, the cell may produce odd proteins and can under certain conditions become cancerous.

2) Another way a virus may cause cancer is when they multiply so quickly that they destroy a portion of the tissue around them. An immune response such as inflammation or regeneration may occur in order to help rejuvenate the tissue.

Both inflammation or regeneration will cause the normal cells to proliferate (divide rapidly) to help compensate for the massive cell loss. Sometimes, this can back-fire and instead of filling in the spaces and then stopping, the cells keep dividing. Many cells dividing out of control may spell disaster.

3) All cells contain sequences of DNA that if turned on, may cause a tumor to develop (these sequences are called oncogenes). A virus may cause an oncogene to become activated.

4) A viral infection may attack the immune system and eventually suppress it or it can just “sidetrack” the immune system from taking care of other problems. If this happens then a small tumor that may have been detected and destroyed by the immune system will have the opportunity to thrive.