MDS is myelodysplastic syndrome, a heterogeneous group of diseases characterized by pathological hematopoiesis and high risk of transformation to leukemia, manifesting as a reduction in one or more lines of blood cells. It is clinically divided into three types: low-risk group, intermediate-risk group and high-risk group, each of which has a marked difference in survival. 1. Low-risk group: Patients’ disease progresses slowly, and the average survival of patients is about 6 years, and individual patients can reach about 6-10 years. 2. Intermediate-risk group: Patients are prone to anemia and infection, and about 20% of them can turn into acute leukemia. The median survival period is about 2-3 years; 3. High-risk group: Patients can turn into acute leukemia due to the high risk of transformation to leukemia, more than 60% of them can turn into acute leukemia, which is not effective to common chemotherapy, and the survival period of patients is about 6-12 months.