Cancer grows out of cells in the body. Normal cells multiply when the body needs them, and die when they are damaged or the body doesn't need them.
Cancer appears to occur when the genetic material of a cell becomes changed. This results in cells growing out of control. Cells divide too quickly and do not die in a normal way.
There are many kinds of cancer. Cancer can develop in almost any organ or tissue, such as the lung, colon, breast, skin, bones, or nerve tissue.
There are many risk factors for cancer, including:
- Benzene and other chemicals
- Drinking too much alcohol
- Environmental toxins, such as certain poisonous mushrooms and a type of poison that can grow on peanut plants (aflatoxins)
- Genetic problems
- Radiation exposure
- Too much sunlight exposure
The cause of many cancers remains unknown.
The most common cause of cancer-related death is lung cancer.
In the U.S., skin cancer is the most commonly diagnosed cancer.
In U.S. men, other than skin cancer the three most common cancers are:
In U.S. women, other than skin cancer the three most common cancers are:
- Breast cancer
- Lung cancer
- Colorectal cancer
Some cancers are more common in certain parts of the world. For example, in Japan, there are many cases of stomach cancer. But in the United States, this type of cancer is less common. Differences in diet or environmental factors may play a role.
Some other types of cancer include: