What happens to a cell when it becomes cancerous?

Answer 1

I see two different questions here- what happens within a cell once it is cancerous, and what makes a cell become cancer. I'll try to answer both:

Every cell in your body has a specific function- skin cells, for example, are born, mature and die in a pre-planned way. This is what keeps us safe from the environment: your skin cells divide to produce more cells to replace those that were lost while the older cells are told to die so we don't become enormous with too many layers of cells. In cancer, the cells don't behave like they should. All cancers...and I mean ALL cancers... are a disease of the DNA. The DNA is the recipe for everything your body does. In normal cells, it controls what happens as in my example above for the skin cell. If the DNA gets "whacked", that process breaks down, and cells divide too quickly, don't do what they're supposed to, and refuse to die when they should. To answer the second part of your question (as I see it), the DNA can be "whacked" by a number of different causes: radiation (like from the sun; sunburn is bad enough, but too much can result in a skin cancer), chemicals (like cigarette smoke, which can cause lung cancer), viruses (like HPV which causes Cervical cancer)...even genetics play a role.

Answer 2

Cancer causes the normal cells of the body to grow and divide uncontrollably. Eventually these cancerous cells will become tumors or growths and may spread to other parts of the body.