CANCER EXPLAINED

In a healthy body, cells grow, divide, and die in an orderly fashion in the body. During the early years of a person's life, normal cells divide more rapidly until the person becomes an adult. After that, the cells in most parts of the body divide only to replace any worn-out or dying cells and to repair injuries. Cancer develops when the cells in a certain part of the human body begin to grow and divide uncontrollably. Because of this, they outlive the normal cells and continue to form new abnormal cells, instead of dying, thus damaging the cells' DNA.
In healthy conditions, the body naturally can repair damaged DNA, however with the presence of cancer cells, this is not possible. A person can inherit damaged DNA, which would account for inherent cancers, or a person's DNA can become damaged due to something in the environment such as smoking.

Cancer usually forms as a tumor, however some cancers (such as leukemia), do not form as tumors, but instead originate in the blood and make their way to other tissues in the body where they grow and spread, and oftentimes replace even the normal tissue. This process is called metastasis. Regardless of where a cancer may spread, however, it is always named for the place where it originates. For instance, breast cancer that spreads to the liver is still called breast cancer, not liver cancer.

Carcinomas
The most common types of cancer, arise from the cells that cover external and internal body surfaces.
Lung, breast, and colon are the most frequent cancers of this type in the United States.
Sarcomas
Cancers arising from cells found in the supporting tissues of the body such as bone, cartilage, fat, connective
tissue, and muscle.
Lymphomas
Cancers that arise in the lymph nodes and tissues of the body's immune system.
Leukemias
Cancers of the immature blood cells that grow in the bone marrow and tend to accumulate in large numbers in the bloodstream.

Different types of cancer can behave very differently. For example, lung cancer and breast cancer are very different diseases. They grow at different rates and respond to different treatments. That is why people with cancer need treatment that is aimed at their particular kind of cancer.
Over one million people get cancer each year. Approximately one out of every two American men and one out of every three American women will have some type of cancer at some point during their lifetime. Anyone can get cancer at any age; however, about 77% of all cancers are diagnosed in people age of 55 and older. Although cancer occurs in Americans of all racial and ethnic groups, the rate of cancer occurrence varies from group to group.

Today, millions of people are living with cancer or have been cured of the disease. The sooner a cancer is found and the sooner treatment begins, the better a patient's chances are of a cure.

American Cancer Society Homepage

National Cancer Institute