“In the United States, 1 in 3 people will be diagnosed with cancer during their lifetime. Here is some information to help you better understand what cancer is.

Cancer needs to be understood that it is more than just one disease. There are many types of cancer, and it can develop anywhere in the body. Cancer is a group of diseases where abnormal cells grow out of control and crowd out normal cells. It affects 1 in 3 people in the United States. Chances are that you or someone you know has been affected by cancer.

There are many different kinds of cancer, but they all involve abnormal cells. Cancers often have these features:

• Gene changes (mutations): Cancer cells have changes in their genes that make them abnormal. Some of these gene changes may be passed down from a parent (inherited mutations), while others may happen later in life (acquired mutations).
• Uncontrolled cell growth: Most abnormal cells die off or are unable to reproduce. But cancer cells can keep growing and dividing to make more abnormal cells. Cancer cells can crowd out normal cells.
• Tumor formation: Not all cancer cells form tumors, and not all tumors are cancer. But many types of cancer cells do clump together to form tumors.
• Cancer spread (metastasis): Cancer cells can invade nearby tissues, and many can even spread to other parts of the body.

Many types of abnormal cell growths have some of these features, but not all of them are cancer.

Cancer starts when something goes wrong in the normal process of cells growing and dividing to make new cells. A cell’s genes (pieces of DNA that tell the cell how to function) change and make the cell abnormal. Most cells die if they become abnormal, but some gene changes allow cells to survive, grow, and divide to make more abnormal cells.

Gene changes that lead to cancer can have many possible causes. Lifestyle habits, genes you get from your parents, and being exposed to certain chemicals or radiation can all play a role. Many times, there is no clear cause.

Cancers are often grouped into two main categories:

• Blood (hematologic) cancers start in blood cells or blood-forming tissues. These include leukemia, lymphoma, and multiple myeloma.
• Solid tumor cancers develop in organs or tissues. The most common solid tumors are breast, prostate, lung, and colorectal cancers.

It’s very important to know the type (and subtype) of cancer before starting treatment, if possible. Knowing the exact type helps doctors know which treatment will work best.”

American Cancer Society (What Is Cancer? | Cancer Basics | American Cancer Society)