Cancer is a group of many related diseases that begin in cells, the body's basic unit of life. Normally, cells grow and divide to produce more cells only when the body needs them. Sometimes, however, cells become abnormal and keep dividing to form more cells without control or order, creating a mass of excess tissue called a tumor. Tumors can be malignant (cancerous) or benign (not cancerous).
The cells in malignant tumors can invade and damage nearby tissue and organs. Cancer cells can also break away from a malignant tumor and travel through the bloodstream or lymphatic system to form new tumors in other parts of the body.
Most cancers are named for the organ or type of cell in which they begin. For example, cancer that begins in the lung is lung cancer, and cancer that begins in cells in the skin known as melanocytes is called melanoma.
When cancer cells spread (metastasize) from their original location to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary tumor. For example, if lung cancer spreads to the brain, the cancer cells in the brain are actually lung cancer cells. The disease is called metastatic lung cancer (it is not brain cancer).
Use the links below to find information on specific types of cancer, including treatment options, expertise at The James, clinical trials, and frequently asked questions.
More information about Cancer Treatment, Supportive Care, Prevention & Screening, Genetics, and Complementary & Alternative Medicine is available from the National Cancer Institute.