ON THIS PAGE: You will find some basic information about this disease and the parts of the body it may affect. This is the first page of Cancer.Net’s Guide to Myelodysplastic Syndromes (MDS). Use the menu to see other pages. Think of that menu as a roadmap for this entire guide.
About the blood and bone marrow
Bone marrow is the spongy, red tissue found in the center of large bones. It stores immature cells called stem cells. Stem cells usually mature into white blood cells, red blood cells, and platelets during a process called hematopoiesis. These cells have different functions in the body:
Red blood cells carry oxygen throughout the body
White blood cells fight infection
Platelets form clots to stop bleeding
About myelodysplastic syndromes
Myelodysplastic neoplasms or syndromes, also known as MDS, are a group of blood and bone marrow disorders. MDS is considered a type of cancer.
In MDS, stem cells do not mature as expected. This means there are too many immature cells, called blasts, and abnormally developed cells, called dysplastic cells. There are also too few healthy mature cells, causing the bone marrow to not work well or to stop working. This means there are less healthy red blood cells, white blood cells, and/or platelets. The numbers of blood cells are often called blood cell counts (see Diagnosis).
People with MDS often have co-existing conditions caused by the decrease in healthy cells, including:
Anemia, which is a low red blood cell count
Neutropenia, which is a low white blood cell count
Thrombocytopenia, which is a low platelet count
Dysplastic white blood cells and platelets, in particular, may not work well. Even if the number of blood cells is normal in a person with MDS, their blood and bone marrow cells can still be abnormal.
There are several subtypes of MDS. Some subtypes of MDS may eventually turn into acute myeloid leukemia (AML). AML is a cancer of the blood in which immature cells called blasts increase and grow more quickly.
Looking for More of an Introduction?
If you would like more of an introduction, explore these related items. Please note that these links will take you to other sections on Cancer.Net:
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Cancer Terms. Learn what medical phrases and terms used in cancer care and treatment mean.
The next section in this guide is Statistics. It helps explain the number of people who are diagnosed with MDS and general survival rates. Use the menu to choose a different section to read in this guide.