What is Cancer?

Cancer is defined as a disease in which abnormal cells begin to divide uncontrollably and invade healthy tissue. Cancerous cells move throughout the body via blood and lymph systems (lymph is a clear fluid that travels through the body, carrying infection-fighting cells).

There are more than one hundred different forms of cancer, and most are named for the organ or cell type in which they manifest. These different types are grouped into categories:

Leukemia – cancer that begins in the bone marrow or other blood-forming tissues, and prompts abnormal blood cells to be developed. These abnormal cells eventually enter the blood stream.

Carcinoma – a cancer that begins in the skin, or tissues that cover internal organs.

Lymphoma/Myeloma – cancer that occurs in the immune system.

Sarcoma – cancer found in the bones, cartilage, muscles, blood vessels, fat or other connective body tissue.

Central Nervous System – cancer that forms in the brain or spinal cord.

The National Cancer Institute has a more comprehensive Dictionary of Cancer Terms if you’re interested in learning more about the various types of cancer.

Here in the United States, some forms of cancer are diagnosed more frequently than others, including breast cancer, bladder cancer, colon cancer, leukemia, lung cancer, prostate cancer, skin cancer, and melanoma. There are also very rare types of cancer, too that affect a smaller population of people but are very aggressive, like mesothelioma cancer.

Many forms of cancer can be prevented by making good lifestyle choices. For example, we’ve all heard that indoor tanning booths can cause skin cancer, and we know that cigarette smoking causes lung cancer. Other forms of cancer occur without a concrete explanation. But no matter what the cause of a person’s cancer, the devastation felt following diagnosis is usually the same.

The National Cancer Institute states that, in 2009, 1,479,350 new cases of cancer were reported (and that number does not even include nonmelanoma skin cancers!) Approximately 562,340 people died as a result of cancer last year. The number of Americans who lost their battle with cancer in 2009 is about 9,000 more individuals than the population of Washington, DC back in 2004. Pretty startling statistics, considering that many forms of cancer can be totally avoided by making the right lifestyle decisions!

When you take a look at the numbers, it’s no surprise that almost everyone knows cancer in some way. While the numbers might be scary, advancements in the field of oncology (the study and treatment of cancerous tumors) are promising. More people know the causes of cancer, and how to prevent it, and countless Americans are adopting an anticancer lifestyle. DYKC is committed to increasing awareness about various forms of cancer with the goal of decreasing the number of individuals diagnosed.


National Cancer Institute

Page modified May 18, 2010.