MDS refers to a heterogeneous group of clonal hematopoietic stem cell (HSC) disorders, resulting from acquired genetic or epigenetic aberrations. They are collectively characterized by bone marrow dysfunction, dysplasia, peripheral blood cytopenias, ineffective hematopoiesis, and reduced genomic stability.1-5 According to the World Health Organization (WHO), MDS is neoplastic and thus is classified as cancer.6 Furthermore, development of acute myeloid leukemia (AML) is also a significant risk in MDS, with 25% to 30% of patients progressing to AML.7,8
Patients with MDS experience significant cytopenias.8,9
- Anemia is the most common cytopenia, affecting approximately 90% of patients at the time of MDS diagnosis7
- Neutropenia is observed in approximately 50% of patients10
- Thrombocytopenia occurs in approximately 40% of patients9
Because MDS share several characteristics and symptoms, such as cytopenias, with many other disorders, it is important to differentiate MDS from pre-MDS disorders and other syndromes.11,12
MDS may be de novo (also called primary) or treatment-related (t-MDS, also called secondary).4,13
- t-MDS can occur as a late complication after receiving radiotherapy, chemotherapy, or immunosuppressive therapy14
- Two types of t-MDS/AML are recognized, depending on the causative therapeutic exposure: an alkylating agent/radiation-related type and a topoisomerase II inhibitor-related type15
There are several differences between de novo MDS and t-MDS. Characteristics that may differ include:
||De Novo MDS
|Percentage of MDS patients diagnosed/year
|Chromosomal instabilities with deletions and translocations
||Normal or complex16
||~90% carry at least one somatic mutation18
||TP53 may be mutated in ~40% of cases19
Learn more about the epidemiology of MDS.
Learn more about chromosomal, epigenetic, and mutational abnormalities in MDS.
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