Cancer sometimes grows up the body. Sometimes it grows down, too. Cancer cells spread, or metastasize, through the bloodstream or a system of lymph nodes and channels that extend throughout the body. Experts at the National Cancer Institute say that lung cancer often spreads to the brain or bones, and colon cancer to the liver. Breast cancer tends to metastasize to the bones, lungs, liver, or brain. But each type of cancer may appear in other organs of the body, too.