What Is It?
Leukemia is a form of cancer that affects the body’s ability to make healthy blood cells. It starts in the bone marrow, the soft center of various bones. This is where new blood cells are made. Blood cells include
- Red blood cells, which carry oxygen from the lungs to the body’s tissues and take carbon dioxide to the lungs to be exhaled
- Platelets, which help blood clot
- White blood cells, which help fight infections, viruses, and diseases.
Although cancer can affect red blood cells and platelets, leukemia generally refers to cancer of the white blood cells. The disease usually affects one of the two major types of white blood cells: lymphocytes and granulocytes. These cells circulate throughout the body to help the immune system fight off viruses, infections, and other invading organisms. Leukemias arising from lymphocytes are called lymphocytic leukemias; those from granulocytes are called myeloid, or myelogenous, leukemias.
To continue reading this article, you must log in.
Subscribe to Harvard Health Online for immediate access to health news and information from Harvard Medical School.
- Research health conditions
- Check your symptoms
- Prepare for a doctor's visit or test
- Find the best treatments and procedures for you
- Explore options for better nutrition and exercise
I'd like to receive access to Harvard Health Online for only $4.99 a month.Sign Me Up
Already a member? Login ».
As a service to our readers, Harvard Health Publishing provides access to our library of archived content. Please note the date of last review or update on all articles.
No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.