Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems.
The three ways that cancer spreads in the body are:
Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for the organ or type of cell in which they start. For example, cancer that begins in the colon is called colon cancer whereas cancer that begins in basal cells of the skin is called basal cell carcinoma.
Nineteen of the most common types of cancer are described in detail on this site plus four types of blood cancers. Other types of cancer can be found at the National Cancer Institute website where the disease information on this website originated. Questions about terms used in the cancer descriptions can be found in the Cancer Glossary and Drug Dictionary.