But sometimes cells lose their ability to limit and direct their growth. Too much tissue forms and tumors develop. Or these abnormal cells, cancer cells, deprive the normal cells of nourishment and space, causing harm to the body. Some tumors are benign - not cancer. They do not spread and rarely threaten life.
Malignant tumors are cancer.
They invade nearby healthy tissue and organs, and malignant cells can spread, or metastasize, to distant parts of the body. Early detection and treatment of cancer are most likely to prevent the cancer from spreading elsewhere in the body. If there is a history of cancer in your family you should talk with your doctor. And it is important to know the early warning signs of cancer. More is being understood about cancer all of the time - the causes for cancer, and how to prevent and treat it.