What makes cancer cells different from normal cells?

In order to understand cancer, one needs to understand the cancer cell. The key characteristics of a cancer cell that make it different from most normal cells in the body are its abilities to grow unregulated by the body's defense, the immune system, and usually (though not always) to metastasize or spread to distant sites in the body through lymphatic channels and blood vessels. Cancer cells arise generally from damaged deoxyribonucleic acid (DNA), the building material that makes cells. Some people are born with this damaged DNA, thanks to their parents. Inherited cancers constitute about 10% of all cases in the United States. For most other patients who develop cancer, however, most of the damage occurs as a result of exposures or events that occur after they're born.