Transformation of myelodysplastic syndromes into acute myeloid leukemias.
BACKGROUND
Myelodysplastic syndromes (MDSs), also called preleukemias, are a group of myeloid hematopoietic malignant disorders. We studied the transformation of MDS into acute myeloid leukemia (AML).


METHODS
Leukemic transformation in 151 patients with MDS was dynamically followed up. The clinical manifestation, peripheral blood and bone marrow condition, karyotypes, immunophenotypes, response to treatment, and prognosis of AML evolution from MDS (MDS-AML) were also observed.


RESULTS
During the course of this study, over the past eight years and seven months, 21 (13.91%) of 151 MDS patients progressed to overt leukemia, with a median interval of 5 (1 - 23) months. There were no significant differences between rates of leukemic transformation in comparison with the refractory anemia (RA), RA with excess of blasts (RAEB), and RAEB in transformation (RAEB-t) patient groups. Transformation occurred either gradually or rapidly. There were five parameters positively correlated to leukemic transformation: under 40 years of age, pancytopenia of 3 lineages, more than 15% blasts in the bone marrow, at least two abnormal karyotypes, and treatment with combined chemotherapy. All of the 21 patients with leukemia suffered from MDS-AML, and most of them were M2, M4, or M5. Two (9.52%) MDS-AML patients developed extramedullary infiltration. Leukopenia was found in 47.62% of these patients. Two thirds of these patients, whose bone marrows were generally hypercellular, suffered from neutropenia. After developing AML, 8 (47.06%) patients developed abnormal karyotypes. High expression of immature myeloid antigens, including CD33 [(49.83 +/- 24.50)%], CD13 [(36.38 +/- 33.84)%], monocytic antigen CD14 [(38.50 +/- 24.60)%], and stem cell marker CD34 [(34.67 +/- 30.59)%], were found on bone marrow mononuclear cells from MDS-AML patients after leukemic transformation. In some cases, lymphoid antigens, such as CD5, CD7, CD9, and CD19, coexisted with myeloid antigens. A low complete remission rate (31.25%) and a short survival time, with median survival of 6 (1 - 28) months, were found in patients with MDS-AML treated by induction chemotherapy.


CONCLUSIONS
MDS has a high risk of developing into AML, either gradually or rapidly. Patients with MDS-AML have specific biological characteristics and a worse prognosis.
Shi
Jun
J
First Department of Clinical Hematology, Hospital of Blood Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Tianjin 300020.
Shao
Zong-hong
ZH
Liu
Hong
H
Bai
Jie
J
Cao
Yan-ran
YR
He
Guang-sheng
GS
Tu
Mei-feng
MF
Wang
Xiu-li
XL
Hao
Yu-shu
YS
Yang
Tian-ying
TY
Yang
Cong-li
CL
D000293:Adolescent; D000328:Adult; D000368:Aged; D002869:Chromosome Aberrations; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D015470:Leukemia, Myeloid, Acute / Q000209:etiology* / Q000235:genetics / Q000276:immunology; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000150:complications* / Q000235:genetics / Q000276:immunology; D011379:Prognosis