Study on prognostic significances of different cytogenetic risk categories in patients with primary myelodysplastic syndromes / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze significances of different cytogenetic categories for prognostic stratification in patients with primary myelodysplastic syndromes (MDS).</p><p><b>METHODS</b>Chromosomal abnormalities of 532 primary MDS patients were categorized according to cytogenetic categories of International Prognostic Scoring System (IPSS), Revised IPSS (IPSS-R), and German-Austrian (G-A). Prognostic impacts of different cytogenetic categories and frequent isolated anomalies were investigated.</p><p><b>RESULTS</b>Of 532 patients, 346(65%) patients had clonal cytogenetic abnormalities, including 200(38%) patients had 1 abnormality, 61(11%) patients had 2 abnormalities, and 85(16%) patients had complex abnormalities. Trisomy 8 was the most frequent karyotype abnormality, occurring in 31% of the patients with clonal cytogenetic abnormalities, other frequent anomalies were -7/del(7q)(13%), del(20q)(12%), del(5q)(9%), -18(5%), -21(5%), i(17q)(5%), -Y(4%), -17(4%), +21(4%), -13/del(13q)(4%), and -22(4%). The proportion of poor karyotypes of IPSS was higher in RAEBI and RAEBII among the World Health Organization classifications than in subgroups with less than 5% blasts. The follow-up data were available for 310 patients with a median follow-up duration of 14.5 months. Median survival was 59 months for patients with normal karyotypes and 26 months for those with abnormal karyotypes. According to IPSS cytogenetic categories, the median survivals of good-risk subgroup, intermediate-risk subgroup and poor-risk subgroup were 59, 43 and 12 months, respectively (P < 0.01). For IPSS-R cytogenetic groups, the median survivals of good-risk subgroup, intermediate-risk(int-risk) subgroup, poor-risk and very poor-risk subgroup were 59, 36, 15, and 10 months, respectively (P < 0.01). According to G-A classification, the median survivals of good-risk subgroup, int-1-risk subgroup, int-2-risk subgroup and poor-risk subgroup were 59, 44, 15, and 11 months, respectively (P < 0.01). In frequent isolated karyotypic abnormalities, +8 had a median survival of 44 months, i(17q) had a median survival of 12 months, and -7/del(7q) had a median survival of 14 months.</p><p><b>CONCLUSION</b>In comparison with IPSS and G-A categories, IPSS-R cytogenetic categories are more sophisticated, and can stratify prognosis effectively, but prognostic significances of some karyotypes in IPSS-R still need to be confirmed.</p>

Cyclosporine A in combination with thalidomide for the treatment of patients with myelodysplastic syndromes / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the efficiency and side-effects of the combination of cyclosporine A (CsA) and thalidomide in patients with myelodysplastic syndromes (MDS).</p><p><b>METHODS</b>A total of thirty-seven patients with MDS-RCMD or-RAEB-I were treated with CsA in combination with thalidomide. The initial CsA dose of 3 mg×kg(-1)×d(-1) was administered, all patients had their CsA blood concentration concurrently monitored until it reached and maintained between 100 and 200 µg/L. The initial dose of thalidomide was 50 mg/d, with increasing dose of 50 mg every week until the maximum of 200 mg/d. The hematological response was assessed according to the modified criteria of the International Working Group, and adverse events were graded with the Common Toxicity Criteria (v3.0) of the National Cancer Institute. The response duration and overall survival of the patients were also observed.</p><p><b>RESULTS</b>19/37 cases (51.4%) achieved hematologic improvement (HI)-erythroid response (HI-E), 9/29 cases (31.0%) HI-platelet response (HI-P) and 7/33 cases (21.2%) HI-neutrophil response (HI-N). 15 of 32 transfusion-dependent patients (46.9%) achieved transfusion independence. The median response duration of HI-E, HI-P and HI-N were 88 (4 - 88) weeks, 78 (8 - 84(+)) weeks and 78 (10 - 84(+)) weeks respectively. The median overall survival was 52 months on a 29 (4 - 103) months median follow-up. Some patients developed grades I-II hepatic or nephritic impairment, constipation, lethargy, dizziness, edema, rashes or numbness, and all were tolerable and reversible. No grade III or severer adverse events were observed.</p><p><b>CONCLUSION</b>CsA in combination with thalidomide appears to be effective mainly in inducing HI-E and relatively well-tolerated for the treatment of patients with MDS.</p>

Re-evaluation of classification of myelodysplastic syndromes with low percentage bone marrow blasts / 中华血液学杂志

<p><b>OBJECTIVE</b>To apply the WHO criteria and the minimal diagnostic criteria to the classification of myelodysplastic syndromes (MDS) with low percentage (< 0.050) bone marrow (BM) blasts.</p><p><b>METHODS</b>Two hundred and ten MDS patients with less than 0.050 BM blasts diagnosed between 1988 and 2005 according to FAB criteria were retrospectively reclassified with WHO criteria (2001) and minimal diagnostic criteria.</p><p><b>RESULTS</b>According to the WHO criteria, 5 patients were diagnosed as refractory anemia (RA), 7 as refractory anemia with ringed sideroblasts (RARS), 76 as refractory cytopenia with multilineage dysplasia (RCMD), 9 as RCMD-RS, 35 as MDS-unclassified (MDS-U), 3 as 5q - syndromes, and the rest 75 patients could not be classified suitably. Among the latter 75 patients 16 BM smears showed dysplasia in more than 2 cell lineage but only unilineage cytopenia in peripheral blood (PB). Nine of them were reclassified as RCMD after followed up for more than half a year. Forty-four BM smears showed erythroid dysplasia only, but bicytopenia or pancytopenia in PB. Twenty-seven of them were classified as RCMD after follow-up. Fifteen BM smears not showed dysplasia in any myeloid lineage were reclassified as MDS (5 patients), HS-MDS (5 patients) and idiopathic cytopenia of uncertain significance (ICUS) (5 patients) according to the MDS minimal diagnostic criteria.</p><p><b>CONCLUSION</b>According to WHO criteria (2001), RA is the least diagnosis in MDS. The minimal diagnostic criteria for MDS classification of patients not fulfilled the standard criteria of MDS.</p>

Studying of clinical and laboratory features of chronic eosinophilic leukemias /hypereosinophilic syndrome / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the clinical and laboratory features of chronic eosinophilic leukemias (CEL) and hypereosinophilic syndrome (HES).</p><p><b>METHODS</b>The clinical manifestations, laboratory parameters were retrospectively analyzed in 20 patients with HES/CEL. Detection of the FIP1L1-PDGFRA fusion gene was performed by nested RT-PCR. JAK2 V617F mutation screening was processed through allele-specific PCR combined with sequence analysis. PCR-RFLP was used to discriminate homozygous from heterozygous mutation patterns. TCR gamma rearrangement was detected by PCR.</p><p><b>RESULTS</b>Of the 20 patients, 19 were males and one female, with a median age of 33 (20 to 57) years. The FIP1L1-PDGFRA fusion gene positivity in bone marrow mononuclear cells in 12 cases was identified. All the breakpoints were identified by direct sequencing of cloned RT-PCR products in FIP1L1 intron 10 - 12 and in PDGFRA exon 12. In CEL the most common involved organs were lungs, heart and nervous system. Splenomegaly was significantly more frequent in CEL than in HES (92.5% vs 42.5%, P = 0.031). Anemia and myelofibrosis were common in CEL. There was no significant difference in circulating absolute eosinophil, leukocyte, platelet counts, hemoglobin level and percentages of eosinophil and blast cell in bone marrow between CEL and HES. The morphological abnormalities of eosinophils on bone marrow smear were easily found in CEL, including hypogranularity, and cytoplasmic vacuolization, increased basophilic granule. One patient with HES was found to have heterozygous JAK2 V617F mutation. Six patients had TCR gamma rearrangement, including 4 CEL and 2 HES.</p><p><b>CONCLUSIONS</b>(1) There is a male predominance in HES/CEL, and the median age was in the thirties. (2) The most common involved organs in CEL were lung, heart and nervous system. Bone marrow morphology might be of a little help in diagnosis of CEL. (3) JAK2 V617F may be involved in the pathogenesis of HES. (4) Patients with CEL carried the FIP1L1-PDGFRA fusion gene and TCR gamma rearrangement concurrently, their relationship warrants further study.</p>

Preliminary study of diagnosis of patients with myelodysplastic syndromes by routine laboratory parameters / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the value of routine laboratory parameters in diagnosis of myelodysplastic syndromes (MDS) and differential diagnosis of patients with hypoplastic MDS from chronic aplastic anemia (CAA) for providing reference standard for primary hospitals.</p><p><b>METHODS</b>The laboratory parameters at diagnosis of 152 MDS patients with less than 0.05 bone marrow blasts and 86 CAA patients were retrospectively analyzed.</p><p><b>RESULTS</b>There were significant differences between MDS and CAA in Hb, red cell distribution width-coefficient variation (RDW-CV), immature reticulocyte fraction (IRF), BPC, the ratio of G1 (the sum percentage of myeloblast and promyelocyte) to G2 (the sum percentage of neutrophilic myelocyte and metamyelocyte) (Ratio G), the ratio of El (the sum percentage of proerythroblast and early erythroblast) to E2 (the sum percentage of intermediate erythroblast and late erythroblast) (Ratio E), megakaryocyte count (Meg), erythroblast PAS, neutrophil alkaline phosphatase (N-ALP), and serous levels of indirect bilirubin (IBIL), lactose dehydrogenase (LDH), folic acid (FA), VitB12 and ferritin. Chromosome abnormalities were found in 74 MDS patients (48.7%) but in none of CAA patients (P < 0.001). Furthermore, for differentiating MDS with less than 0.05 blasts from CAA, the sensitivity and specificity of combination of Meg, PAS, and IBIL level was 89.1% and 92.7%, the Youden index (gamma) was 0.818. Moreover, in the seven hypoplastic MDS cases, BPC, myeloblast percentage, Ratio G, Meg, erythroblast PAS and FA were statistically different from those of CAA; the sensitivity and specificity of combination of PAS and BPC was 85.7% and 100%, the gamma was 0.857; the sensitivity and specificity combination of Ratio G, Meg PAS was 85.7% and 98.8% respectively, the gamma was 0.845.</p><p><b>CONCLUSION</b>The routine laboratory parameters, especially BPC, Meg, Ratio G, PAS, IBIL may be helpful for the diagnosis of MDS and differential diagnosis of hypoplastic MDS from CAA.</p>

Long-term therapeutic outcome of patients with acute promyelocytic leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze the long-term therapeutic outcome of patients with acute promyelocytic leukemia(APL).</p><p><b>METHODS</b>Newly diagnosed APL patients were treated with ATRA as induction therapy followed by 3-4 courses of combined consolidation chemotherapy and 2 year maintenance therapy with ATRA and 6-MP + methrotrexate, alternatively. Patients were regularly monitored with nested RT-PCR for PML-RARalpha fusion transcript at the end of consolidation chemotherapy and in the following 4 to 5 years.</p><p><b>RESULTS</b>A total of 81 patients with APL were entered the trial, 75 (92.6%) patients achieved CR. Early death (ED) rate was 6.6%. ED patients had significantly higher WBC count and higher percentage of peripheral promyelocyte than those achieved CR. Of 65 patients received consolidation, 60 (92.3%) were proved PML-RARalpha fusion gene negative at the end of the 3rd courses and 3 (4.6%) the end of the 4th courses of consolidation. The mean follow-up was 21.2 (8-64) months, 6 patients relapsed (relapse rate 9.2%). The 5-year Kaplan-Meier estimates of overall survival (OS) rate was (86.6 +/- 4.6)%. For 65 patients received consolidation therapy, the 5-year relapse-free survival (RFS) rate was 82.7%. COX-regression analyses showed only high WBC count (>10 x 10(9)/L) had an adverse prognostic influence on OS.</p><p><b>CONCLUSION</b>More than 80% of APL patients treated with systemic therapy could experience long-term relapse-free survival.</p>

Study of genes involved in chronic myeloid leukemia with t (3; 21) (q26; q22) in blastic crisis / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore genes involved in chronic myeloid leukemia (CML) with t (3; 21) (q26; q22) chromosome translocation in blastic crisis.</p><p><b>METHODS</b>A case of CML patient with t (3; 21) (q26; q22) in blastic crisis was reported. AML1 and bcr/abl genes were detected by FISH in interphase and metaphase cells. Genes involved in t (3; 21) (q26; q22) were analysed by RT-PCR and sequencing.</p><p><b>RESULTS</b>AML1 gene hybridization signal was detected in der (3) and der (21) chromosomes. AML1-Evi1, AML1-MDS1-Evi1, AML1-EAP fusion transcripts and Evi1 gene were detected in mRNA level, but no AML1-Evi1 fusion transcript. The mRNA expression level of AML1-MDS1-Evi1 fusion gene was 1.58 and 1.54 times higher than that of AML1-MDS1 and AML1-EAP, respectively. The mRNA expression level of Evi1 gene of the patient was 2.71 times higher than that of HEL cell line.</p><p><b>CONCLUSION</b>t (3; 21) (q26; q22) resulted in the AML1-MDS1-Evi1, AML1-MDS1, AML1-EAP fusion transcripts, and Evi1 gene was also activated by the translocation. These secondary aberrations should be the molecular basis of CML patient with t (3; 21) (q26; q22) in blastic crisis.</p>

Clinical and laboratory study of 4 cases of myelodysplastic syndromes with t (1;3) (p36; q21) / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the clinical features of myelodysplastic syndromes (MDS) patients with t (1; 3) (p36; q21) and the expression of the involved genes.</p><p><b>METHODS</b>4 cases of MDS with t (1; 3) (p36; q21) were reported. The expression level of two transcription forms (PR-containing form MEL1 and PR-lacking form MEL1s) of MEL1 gene in normal fetus tissues, 2 healthy donor bone marrows and bone marrows from 3 MDS patients with t (1; 3) (p36; q21) were detected by semiquantitative reverse transcription polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>MDS patients with t (1; 3) (p36; q21) mainly presented with debility. Hemogram was macrocytic anemia, normal or elevated white blood cell and platelet counts. The bone marrow showed tri-lineage dysplasia especially dysmegakaryocytopoiesis. The patients had poor prognosis. MEL1 form was mainly expressed in the normal fetus tissues and healthy bone marrows, while the bone marrow cells from MDS patients with t (1; 3) (p36; q21) mainly or only expressed MEL1s.</p><p><b>CONCLUSIONS</b>MDS patients with t (1; 3) (p36; q21) may be a new unique entity. Overexpression of MEL1s induced by t (1; 3) (p36; q21) might play an important role in the pathogenesis of this entity.</p>

Detection of CBFbeta/MYH11 fusion transcripts and study of the mechanism of leukemogenesis of CBFbeta/SMHHC fusion protein / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore CBFbeta/MYH11 fusion transcripts and its expressing product CBFbeta/SMHHC fusion protein in mechanism of leukemogenesis.</p><p><b>METHODS</b>CBFbeta/MYH11 fusion transcripts were detected by combined RT-PCR with sequencing. Transcription assays were examined using pM-CSFR-Luc as reporting plasmid, and subcellular localization of encoding proteins were assayed by double immunofluorescent staining and Western blot.</p><p><b>RESULTS</b>Two types of CBFbeta/MYH11 fusion transcripts were found in 26 patients with acute leukemia, most being of type A (23/26 cases, 92%) and a few of type D (2/26 cases, 8%). The inhibition of CBF-mediated M-CSFR promotor transactivation by CBFbeta/SMHHC fusion protein was increasing with the increase in amount of the fusion protein. CBFalpha subunit (AML1) located in nucleus, both CBFbeta subunit (CBFbeta) and CBFbeta/SMHHC located in cytoplasm. When AML1 and CBFbeta were coexpressed, CBFbeta still located mainly in cytoplasm, but when AML1 and CBFbeta/SMHHC were coexpressed, CBFbeta/SMHHC located mainly in nucleus.</p><p><b>CONCLUSIONS</b>(1) The types of CBFbeta/MYH11 fusion transcripts of Chinese leukemia patients are almost the same as that reported in western literature. (2) CBFbeta/SMHHC inhibits CBF-mediated transactivation through competing with CBFbeta for binding to AML1.</p>

Investigation of GSTT1, GSTM1 and NQO1 genes polymorphisms in myelodysplastic syndromes / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between GSTM1, GSTT1 and NQO1(C609T) genotypes and myelodysplastic syndromes (MDS) susceptibility and chromosome abnormalities.</p><p><b>METHODS</b>GSTT1, GSTM1 and NQO1(C609T) genotypes were detected in 52 MDS patients and 241 unrelated controls by PCR or PCR-RFLP.</p><p><b>RESULTS</b>The incidence of GSTT1 and GSTM1 null genotype was significantly increased in MDS patients as compared with controls (P = 0.001 and P < 0.001, respectively). In individuals with GSTT1 and GSTM1 null genotype, the odds ratios for MDS risk were elevated to 2.873 (95% CI: 1.491-5.537) and 3.591 (95% CI: 1.717-7.508), respectively. A significantly increased frequency of GSTT(1) null genotype among MDS patients with normal karyotype and increased frequency of GSTM1 null genotype among MDS patients with chromosome abnormalities were found as compared to controls (OR = 5.336, P = 0.005 and P = 0.003, OR = 3.740, respectively). There was no difference in the incidence of NQO1(C609T) genotypes between MDS patients and controls.</p><p><b>CONCLUSION</b>Determination of the GSTM1 and GSTT1 genotypes may be used as a stratification marker to predicate high-risk individuals for MDS.</p>

Karyotypic and IPSS grouping of primary myelodysplastic syndromes patients: a comparison between FAB- and WHO-classification / 中华血液学杂志

<p><b>OBJECTIVE</b>To compare the results of cytogenetic and IPSS grouping of primary myelodysplastic syndromes (pMDS) patients classified by FAB- or WHO classification.</p><p><b>METHODS</b>Two hundred and thirty seven cases of pMDS who were previously classified according to FAB criteria were reclassified with WHO classification. A comparison was made between the results of the two classifications.</p><p><b>RESULTS</b>For the detection rates of cytogenetic abnormality and its risks group, there was no difference among the FAB subgroups but the detection rate was different between the WHO refractory cytopenia with multilineage dysplasia (RCMD) and RA subgroups (74.4% and 42.5%, respectively) (P < 0.001). The percentage of good karyotype abnormalities in RA (65.0%) was higher than that in RCMD (24.4%) (P < 0.001), and the percentages of intermediate and poor karyotype abnormalities in RCMD (48.9% and 26.7%, respectively) were higher than that in RA (27.5% and 7.5%, respectively) (P < 0.05). There was a good correlation between the subgroups and IPSS risk groups for both the WHO classification and the FAB classification, but the WHO classification further reflected the differences between RCMD and RA and RAEB-I and RAEB-II subgroups. The percentage of low-risk group in RCMD (1.1%) was lower than that in RA (10.0%) (P < 0.05), and the percentage of high-risk group in RAEB-II (30.5%) was higher than that in RAEB-I(0) (P < 0.001).</p><p><b>CONCLUSION</b>For the correlation between subgroups and cytogenetic abnormalities and IPSS risk groups, the WHO-classification is better than the FAB-classification.</p>

Clinical and laboratory study of a case of hematidrosis / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the clinical characteristics and pathogenesis of hematidrosis.</p><p><b>METHODS</b>Detailed clinical manifestations and natural history of a patient with hematidrosis were presented. A series of laboratory examinations were performed, and skin pathohistologic features and ultra microscopic structures were observed.</p><p><b>RESULTS</b>The episodes of skin bleeding occurred on any site of the body spontaneously and promptly. The skin surface bloody extravasation has identical cell components as that of peripheral blood. All the results of laboratory tests were normal except a positive Trousseau's test. Skin pathohistological study revealed some intradermal bleeding and emphraxised capillaries. No abnormality was found in sweat glands, hair follicles and sebaceous glands.</p><p><b>CONCLUSION</b>The pathological basis for hematidrosis might be a distinctive vasculitis.</p>

Transformation of myelodysplastic syndromes into acute myeloid leukemias / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>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).</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSIONS</b>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.</p>

Study on the Characteristics of cell cycle and proliferation of CD34+ hematopoietic stem cells in myelodysplastic syndromes / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the characteristics of cell cycle and proliferation of CD34+ hematopoietic stem cells in patients with myelodysplastic syndromes (MDS).</p><p><b>METHODS</b>Propidium iodide staining was used to examine cell cycle parameters (G(0)/G(1), S and G(2)/M) of bone marrow mononuclear cells (BMMNCs) while immunofluorescent double staining and FACS techniques were used to measure Ki67 expression in BM CD34+ cells from normal control, patients with MDS, acute myeloid leukemia preceded by MDS (MDS-AML) and primary AML.</p><p><b>RESULTS</b>There was a statistical up-tendency in G(0)/G(1) phase proportion of BMMNCs whereas a statistical down-tendency in S and G(2)/M phase proportions among normal control, MDS and primary AML. Compared to primary AML, MDS-AML had significantly higher ratios of S (P < 0.05), G(2)/M (P < 0.05) and S + G(2)/M (P < 0.05) phase cells while lower ratio of G(0)/G(1) phase cells (P < 0.05). The proportion of CD34+Ki67+ cells in MDS patients was significantly higher than that in normal control (P = 0.004). So were the percentages of CD34+Ki67+ cells in low-risk [(0.54 +/- 0.49)%, P < 0.05] and high-risk MDS patients [(1.69 +/- 1.66)%, P = 0.022]. Furthermore, there was statistical difference between low-risk and high-risk MDS (P < 0.05). Compared to normal control and primary AML, MDS-patients had the highest proportion of CD34+Ki67+ cells [(16.75 +/- 13.58)%, P < 0.05]. The proportion of CD34+Ki67+ cells in CD34+ cells in MDS patients [(48.50 +/- 20.49)%] was significantly higher than that in normal control [(27.71 +/- 16.04)%, P < 0.01]. So were the low-risk [(51.85 +/- 21.80)%, P = 0.002] and high-risk MDS [(43.93 +/- 18.57)%, P < 0.05]. The proportion of CD34+Ki67+ cells in CD34+ cells in MDS-AML patients [(60.92 +/- 30.12)%] was the highest, and was statistically higher than that in both normal control (P < 0.01) and primary AML patients [(17.01 +/- 15.93)%, P < 0.001]. The proportion of CD34+Ki67+ cells in Ki67+ cells in MDS patients [(4.91 +/- 4.68)%, P < 0.01] was significantly higher than that [(2.43 +/- 2.37)%] in normal controls. In the low-risk MDS group it was (4.11 +/- 3.94)%, (P > 0.05) and in high-risk MDS group it was (5.76 +/- 5.38)%, (P < 0.05).</p><p><b>CONCLUSION</b>High proportion of G(0)/G(1) cells and G(1) phase arrest occurred in MDS. High proliferation capacity of MDS clone, especially that derived from CD34+ cells, might play an important role in the clonal expansion, diseases deterioration and worse prognosis of MDS.</p>