Home HealthTopics Health Centers Reference Library Research
Join us on Facebook Join us on Facebook Share on Facebook
Print this pageEMail this page

Cancer

Cancer Overview

Cancer is Many Different Diseases.

Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems.

Cancer is not just one disease but many diseases. There are more than 100 different types of cancer. Most cancers are named for the organ or type of cell in which they start - for example, cancer that begins in the colon is called colon cancer; cancer that begins in basal cells of the skin is called basal cell carcinoma.

Cancer types can be grouped into broader categories. The main categories of cancer include:

Carcinoma - Cancer that begins in the skin or in tissues that line or cover internal organs. Cancer that start in organs such as breasts or lungs are usually carcinomas.

Sarcoma - Cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue.

Leukemia - Cancer that starts in blood-forming tissue such as the bone marrow and causes large numbers of abnormal blood cells to be produced and enter the blood.

Lymphoma - Cancer that begins in cells of the immune system, usually in lymph nodes. There are two basic categories of lymphomas. One kind is Hodgkin lymphoma, which is marked by the presence of a type of cell called the Reed-Sternberg cell. The other category is non-Hodgkin lymphomas, which includes a large, diverse group of cancers of immune system cells. Non-Hodgkin lymphomas can be further divided into cancers that have an indolent (slow-growing) course and those that have an aggressive (fast-growing) course. These subtypes behave and respond to treatment differently. Both Hodgkin and non-Hodgkin lymphomas can occur in children and adults, and prognosis and treatment depend on the stage and the type of cancer.

Myeloma - Cancer that arises in plasma cells, a type of white blood cell, usually found in blood-forming tissue such as the bone marrow.

Central nervous system cancers - Cancers that begin in the tissues of the brain and spinal cord.

How Cancer Happens in the Body

All cancers begin in cells, the body's basic unit of life. To understand cancer, it's helpful to know what happens when normal cells become cancer cells.

The body is made up of many types of cells. These cells grow and divide in a controlled way to produce more cells as they are needed to keep the body healthy. When cells become old or damaged, they die and are replaced with new cells.

However, sometimes this orderly process goes wrong. The genetic material (DNA) of a cell can become damaged or changed, producing mutations that affect normal cell growth and division. When this happens, cells do not die when they should and new cells form when the body does not need them. The extra cells may form a mass of tissue called a tumor.

Know Your Risk, Get Screened and Stay Healthy

The risk of developing many types of cancer can be reduced by knowing your family medical history, practicing healthy lifestyle habits, such as eating a healthy diet, getting regular exercise, and not smoking. Also, the sooner a cancer is found and treatment begins, the better the chances are that the treatment will be successful, so get regular screenings according to your risk factors.

Source: National Cancer Institute ? What is Cancer?

For more information:

Go to the Cancer health topic, where you can:

Last Reviewed: Jul 08, 2010

Paula  Silverman, MD Paula Silverman, MD
Associate Professor of Medicine
School of Medicine
Case Western Reserve University