Overview.

Cancer is an umbrella term for a large group of diseases caused when abnormal cells divide rapidly, and spread to other tissue and organs. Cancer is one of the leading causes of death in the world.

Cancer Growth and Metastasis

  • In a healthy body, the trillions of cells it’s made of grow and divide, as the body needs them to function daily. Healthy cells have a specific life cycle, reproducing and dying off in a way that is determined by the type of cell. New cells take the place of old or damaged cells as they die. Cancer disrupts this process and leads to abnormal growth in cells. It’s caused by changes or mutations in DNA.
  • DNA exists in the individual genes of every cell . It has instructions that tell the cell what functions to perform and how to grow and divide. Mutations occur frequently in DNA, but usually cells correct these mistakes. When a mistake is not corrected, a cell can become cancerous.
  • But not all tumors are cancerous. Benign tumors are noncancerous and do not spread to nearby tissues. Sometimes, they can grow large and cause problems when they press against neighboring organs and tissue. Malignant tumors are cancerous and can invade other parts of the body.
  • Some cancer cells can also migrate through the bloodstream or lymphatic system to distant areas of the body. This process is called metastasis. Cancers that have metastasized are considered more advanced than those that have not. Metastatic cancers tend to be harder to treat and more fatal.

Types of Cancer

Cancers are named for the area in which they begin and the type of cell they are made of, even if they spread to other parts of the body. For example, a cancer that begins in the lungs and spreads to the liver is still called lung cancer. There are also several clinical terms used for certain general types of cancer:

Carcinoma is a cancer that starts in the skin or the tissues that line other organs.

Sarcoma is a cancer of connective tissues such as bones, muscles, cartilage, and blood vessels.

Leukemia is a cancer of bone marrow, which creates blood cells.

Lymphoma and myeloma are cancers of the immune system.