Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid clonal disorders that originate from hematopoietic stem cells and are characterized by dysplasia of myeloid cells with ineffective hematopoiesis and refractory cytopenias. MDS is known as the prophase of leukemia primarily because of its high risk of transformation to acute myeloid leukemia (AML) during the natural course of the disease. The following is a detailed explanation of this view:
1. Pathological features
of myelodysplastic syndrome Pathological features of MDS include:
-Clonal hematopoiesis: Hematopoietic stem cells from MDS patients have clonal abnormalities, which means that they originate from an abnormal stem cell.
-Dysplasia: In the bone marrow of MDS patients, the development and maturation of blood cells is abnormal, resulting in the production of dysfunctional blood cells.
-High-risk transformation: a significant proportion of MDS patients will eventually develop AML.
2. Relationship
between MDS and AML -Disease progression: MDS is considered a pre-AML stage because patients with MDS may have their disease progress over time, eventually developing AML. This transformation is usually accompanied by an increase in the proportion of blasts in the bone marrow.
-Genetic changes: There is a genetic link between MDS and AML. Patients with MDS often have chromosomal abnormalities that are also common in AML and may be associated with disease progression.
Clinical features: MDS and AML have similarities in clinical signs, such as anemia, bleeding tendency, and increased risk of infection.
3. Why is MDS considered the prophase
of leukemia? -High-risk conversion rate: It is estimated that approximately 30% of patients with MDS will eventually develop AML. This high risk conversion rate allows MDS to be considered as an early stage of AML.
-Pathophysiological Continuity: There is continuity in the pathophysiology of MDS and AML. Clonal hematopoietic stem cells in MDS gradually accumulate more genetic and epigenetic abnormalities, which may eventually lead to the development of AML.
-Treatment strategies: Because patients with MDS are at higher risk of AML transformation, treatment strategies are often aimed at delaying disease progression, while also taking into account the possible need for AML-specific therapies.
4. Risk factors
of MDS transforming to AML -The proportion of blasts in the bone marrow: The higher the proportion of blasts, the greater the risk of transformation to AML.
-Chromosomal abnormalities: Certain specific chromosomal abnormalities are associated with a higher risk of AML transformation.
-MDS subtypes: According to the World Health Organization classification, some MDS subtypes (such as MDS-RAEB and MDS-RAEB-t) have a higher risk of AML transformation than others.
Conclusion
MDS is called the prophase of leukemia, mainly because it has a high risk of transformation to AML in the natural course of the disease. This transformation is not only a clinical transformation, but also a pathophysiological continuity. However, not all patients with MDS develop AML, depending on a variety of factors, including the subtype of the disease, the patient’s genetic background, and the treatment. Therefore, for patients with MDS, it is essential to closely monitor the disease progression and take appropriate treatment measures in time.
