SETD2 deficiency accelerates MDS-associated leukemogenesis via S100a9 in NHD13 mice and predicts poor prognosis in MDS.

SETD2, the histone H3 lysine 36 methyltransferase, previously identified by us, plays an important role in the pathogenesis of hematologic malignancies, but its role in myelodysplastic syndromes (MDSs) has been unclear. In this study, low expression of SETD2 correlated with shortened survival in patients with MDS, and the SETD2 levels in CD34+ bone marrow cells of those patients were increased by decitabine. We knocked out Setd2 in NUP98-HOXD13 (NHD13) transgenic mice, which phenocopies human MDS, and found that loss of Setd2 accelerated the transformation of MDS into acute myeloid leukemia (AML). Loss of Setd2 enhanced the ability of NHD13+ hematopoietic stem and progenitor cells (HSPCs) to self-renew, with increased symmetric self-renewal division and decreased differentiation and cell death. The growth of MDS-associated leukemia cells was inhibited though increasing the H3K36me3 level by using epigenetic modifying drugs. Furthermore, Setd2 deficiency upregulated hematopoietic stem cell signaling and downregulated myeloid differentiation pathways in the NHD13+ HSPCs. Our RNA-seq and chromatin immunoprecipitation-seq analysis indicated that S100a9, the S100 calcium-binding protein, is a target gene of Setd2 and that the addition of recombinant S100a9 weakens the effect of Setd2 deficiency in the NHD13+ HSPCs. In contrast, downregulation of S100a9 leads to decreases of its downstream targets, including Ikba and Jnk, which influence the self-renewal and differentiation of HSPCs. Therefore, our results demonstrated that SETD2 deficiency predicts poor prognosis in MDS and promotes the transformation of MDS into AML, which provides a potential therapeutic target for MDS-associated acute leukemia.

Molecular analysis of patients with polycythemia vera or essential thrombocythemia receiving pegylated interferon α-2a.

Pegylated interferon α-2a (PEG-IFN-α-2a) has previously been shown to induce hematologic and molecular responses in patients with polycythemia vera (PV) or essential thrombocythemia (ET). Here we present a follow-up of a phase 2 trial with PEG-IFN-α-2a treatment in 43 PV and 40 ET patients with detailed molecular analysis. After a median follow-up of 42 months, complete hematologic response was achieved in 76% of patients with PV and 77% of those with ET. This was accompanied by complete molecular response (CMR) (ie, undetectable JAK2V617F) in 18% and 17%, of PV and ET patients, respectively. Serial sequencing of TET2, ASXL1, EZH2, DNMT3A, and IDH1/2 revealed that patients failing to achieve CMR had a higher frequency of mutations outside the Janus kinase-signal transducer and activator of transcription pathway and were more likely to acquire new mutations during therapy. Patients with both JAK2V617F and TET2 mutations at therapy onset had a higher JAK2V617F mutant allele burden and a less significant reduction in JAK2V617F allele burden compared with JAK2 mutant/TET2 wild-type patients. These data demonstrate that PEG-IFN-α-2a induces sustained CMR in a subset of PV or ET patients, and that genotypic context may influence clinical and molecular response to PEG-IFN-α-2a.

Genetic analysis of patients with leukemic transformation of myeloproliferative neoplasms shows recurrent SRSF2 mutations that are associated with adverse outcome.

Leukemic transformation (LT) of myeloproliferative neoplasms (MPNs) is associated with a poor prognosis and resistance to therapy. Although previous candidate genetic studies have identified mutations in MPN patients who develop acute leukemia, the complement of genetic abnormalities in MPN patients who undergo LT is not known nor have specific molecular abnormalities been shown to have clinical relevance in this setting. We performed high-throughput resequencing of 22 genes in 53 patients with LT after MPN to characterize the frequency of known myeloid mutations in this entity. In addition to JAK2 and TET2 mutations, which occur commonly in LT after MPN, we identified recurrent mutations in the serine/arginine-rich splicing factor 2 (SRSF2) gene (18.9%) in acute myeloid leukemia (AML) transformed from MPNs. SRSF2 mutations are more common in AML derived from MPNs compared with LT after myelodysplasia (4.8%) or de novo AML (5.6%), respectively (P=.05). Importantly, SRSF2 mutations are associated with worsened overall survival in MPN patients who undergo LT in univariate (P=.03; HR, 2.77; 95% CI, 1.10-7.00) and multivariate analysis (P<.05; HR, 2.11; 95% CI, 1.01-4.42). These data suggest that SRSF2 mutations contribute to the pathogenesis of LT and may guide novel therapeutic approaches for MPN patients who undergo LT.

Effective Management of Polycythemia Vera With Ropeginterferon Alfa-2b Treatment.

Background: Polycythemia vera (PV) is a myeloproliferative neoplasm. Ropeginterferon alfa-2b is a new-generation polyethylene glycol-conjugated proline-interferon. It is approved for the treatment of PV at a starting dose of 100 µg (50 µg for patients receiving hydroxyurea (HU)) and dose titrations up to 500 µg by 50 µg increments. The study was aimed at assessing its efficacy and safety at a higher starting dose and simpler intra-patient dose escalation. Methods: Forty-nine patients with PV having HU intolerance from major hospitals in China were treated biweekly with an initial dose of 250 µg, followed by 350 µg and 500 µg thereafter if tolerated. Complete hematological response (CHR) was assessed every 12 weeks based on the European LeukemiaNet criteria. The primary endpoint was the CHR rate at week 24. The secondary endpoints included CHR rates at weeks 12, 36 and 52, changes of JAK2V617F allelic burden, time to first CHR, and safety assessments. Results: The CHR rates were 61.2%, 69.4% and 71.4% at weeks 24, 36, and 52, respectively. Mean allele burden of the driver mutation JAK2V617F declined from 58.5% at baseline to 30.1% at 52 weeks. Both CHR and JAK2V617F allele burden reduction showed consistent increases over the 52 weeks of the treatment. Twenty-nine patients (63.0%) achieved partial molecular response (PMR) and two achieved complete molecular response (CMR). The time to CHR was rapid and median time was 5.6 months according to central lab results. The CHRs were durable and median CHR duration time was not reached at week 52. Mean spleen index reduced from 55.6 cm2 at baseline to 50.2 cm2 at week 52. Adverse events (AEs) were mostly mild or moderate. Most common AEs were reversible alanine aminotransferase and aspartate aminotransferase increases, which were not associated with significant elevations in bilirubin levels or jaundice. There were no grade 4 or 5 AEs. Grade 3 AEs were reversible and manageable. Only one AE led to discontinuation. No incidence of thromboembolic events was observed. Conclusion: The 250-350-500 µg dosing regimen was well tolerated and effectively induced CHR and MR and managed spleen size increase. Our findings demonstrate that ropeginterferon alfa-2b at this dosing regimen can provide an effective management of PV and support using this dosing regimen as a treatment option.

Mutational analysis of therapy-related myelodysplastic syndromes and acute myelogenous leukemia.

Therapy-related myelodysplastic syndromes and acute myelogenous leukemia comprise a poor-risk subset of myelodysplastic syndromes and acute myelogenous leukemia. Large-scale mutation profiling efforts in de novo myelodysplastic syndromes have identified mutations that correlate with clinical features, but such mutations have not been investigated in therapy-related myelodysplastic syndromes and acute myelogenous leukemia. Genomic DNA from 38 patient samples were subjected to high throughput polymerase chain reaction and sequenced for TP53, TET2, DNMT3A, ASXL1, IDH1, IDH2, EZH2, EED, SUZ12, RBBP4, SRSF2, U2AF35, and SF3B1. We identified somatic mutations in 16 of 38 (42%) patients. TP53 mutations were the most common lesion, detected in 8 of 38 (21%) patients, followed by TET2 in 4 of 38 (10.5%). Cases with a TP53 mutation or loss of the TP53 locus had a worse overall survival compared to those with wild-type TP53 (8.8 vs. 37.4 months; P=0.0035).

Identification of the STAT5B-RARα fusion transcript in an acute promyelocytic leukemia patient without FLT3, NPM1, c-Kit and C/EBPα mutation.

T(15;17) is the most common chromosomal aberration in patients with acute promyelocytic leukemia (APL), leading to the formation of PML-RARα fusion gene. In a small subset of patients with APL, the RARα gene is fused with different partners. Here, we report a rare APL case with STAT5B-RARα fusion transcript. Cytomorphologic and immunophenotypic analyses showed typical features of APL. However, cytogenetic analysis showed normal karyotype, and interphase fluorescence in situ hybridization (FISH) showed PML-RARα negative. Quantitative RT-PCR also showed PML-RARα negative but STAT5B-RARα positive and sequencing analysis confirmed the result. Molecular markers including FLT3, NPM1, c-Kit and C/EBPα mutation were all negative. To our knowledge, this is the first APL patient with STAT5B-RARα in Chinese population and the fifth patient around the world according to published paper.

Gain-of-function mutation of GATA-2 in acute myeloid transformation of chronic myeloid leukemia.

Acquisition of additional genetic and/or epigenetic abnormalities other than the BCR/ABL fusion gene is believed to cause disease progression in chronic myeloid leukemia (CML) from chronic phase to blast crisis (BC). To gain insights into the underlying mechanisms of progression to BC, we screened DNA samples from CML patients during blast transformation for mutations in a number of transcription factor genes that are critical for myeloid-lymphoid development. In 85 cases of CML blast transformation, we identified two new mutations in the coding region of GATA-2, a negative regulator of hematopoietic stem/progenitor cell differentiation. A L359V substitution within zinc finger domain (ZF) 2 of GATA-2 was found in eight cases with myelomonoblastic features, whereas an in-frame deletion of 6 aa (delta341-346) spanning the C-terminal border of ZF1 was detected in one patient at myeloid BC with eosinophilia. Further studies indicated that L359V not only increased transactivation activity of GATA-2 but also enhanced its inhibitory effects on the activity of PU.1, a major regulator of myelopoiesis. Consistent with the myelomonoblastic features of CML transformation with the GATA-2 L359V mutant, transduction of the GATA-2 L359V mutant into HL-60 cells or BCR/ABL-harboring murine cells disturbed myelomonocytic differentiation/proliferation in vitro and in vivo, respectively. These data strongly suggest that GATA-2 mutations may play a role in acute myeloid transformation in a subset of CML patients.

CAG regimen for refractory or relapsed adult T-cell acute lymphoblastic leukemia: A retrospective, multicenter, cohort study.

Adult patients with relapsed or refractory T-cell acute lymphoblastic leukemia (R/R-T-ALL) have extremely poor prognosis, representing an urgent unmet medical need. Finding an optimal salvage regimen to bridge transplantation is a priority. The CAG (cytarabine, aclarubicin, and G-CSF) regimen was initially used by one group in China, showing unexpectedly promising results in 11 R/R-T-ALL patients. Here, we report the multicenter results of 41 patients who received the CAG regimen as salvage therapy. After one cycle of the CAG regimen, complete remission and partial remission were achieved in 33 (80.5%) and two (4.9%) patients, respectively. Failure to respond was observed in six patients (14.6%). Early T-cell precursor (ETP) (n = 26) and non-ETP (n = 15) patients had a similar CR rate (80.8% vs 80.0%, P = .95). Among 41 patients, allo-HSCT was successfully performed in 27 (66%) patients (22 in CR and 5 in non-CR). With a median follow-up time of 12 months, the estimated 2-year overall survival and event-free survival were 68.8% (95% CI, 47.3%-83.0%) and 56.5% (95% CI, 37.1%-71.9%), respectively. The CAG regimen was well-tolerated, and no early death occurred. Our multicenter results show that the CAG regimen is highly effective and safe, representing a novel choice for adult patients with R/R-T-ALL and providing a better bridge to transplantation.

[The application of fluorescence in situ hybridization in detecting chronic myeloid leukemia].

OBJECTIVE: To evaluate the clinical significance of the application of fluorescence in situ hybridization (FISH) in detecting chronic myeloid leukemia (CML). METHODS: Chromosome preparation was made by using 24-hour culture. FISH technique using dual color dual fusion (DC-DF) BCR/ABL probe was performed in all 158 cases and R-banding was also employed for karyotyping in some patients. RESULTS: Among the 158 cases, 98 cases were Ph positive, of which 69 cases (70.4%) were typical FISH pattern (1R1G2F), the other 29 cases (29.6%) showed 12 different types of atypical FISH pattern. The most frequent atypical patterns found were 1R1G1F in 7 cases (7.1%), 2R1G1F in 5 cases (5.1%), 1R1G2F and 1R1G3F in 4 cases (4.1%), 2R2G1F in 3 cases (3.1%). Karyotype analysis on 18 CML cases with atypical FISH patterns demonstrated that the atypical FISH patterns were due to variant translocation in 3 cases; the additional third signal was because of a supernumerary Ph chromosome. The karyotyping results did not conform to FISH results in four cases suggesting the conceivable mistakes in karyotyping. The 1R1G1F signal pattern seen in 3 cases with classical t(9;22) resulted from the deletion of derivative chromosome 9. The 1R1G2F signal pattern detected in 40% to 64% of interphase cells of 3 cases without Ph chromosome by conventional cytogenetic analysis suggested a submicroscopic translocation. Three cases treated with Glivec or bone marrow transplantation showed normal karyotypes with a small amount of BCR/ABL positive cells by FISH detection. CONCLUSION: FISH technique is of great value for the diagnosis of CML and confirmation of variant translocation, occult Ph translocation, derivative chromosome 9 deletion, therapeutic effect of interferon and Glivec as well as detection of minimal residual disease after bone marrow transplantation.

Outcome of treatment with Hyper-CVAD regimen in Chinese patients with acute lymphocytic leukemia.

Modern intensive chemotherapy regimens have improved the prognosis for adult patients with acute lymphocytic leukemia (ALL). With these regimens, the complete response (CR) rates are approximately 75% and long-term disease-free survival (DFS) rates are about 20-35%. For patients with high-risk ALL, DFS rates are only 20% or less. Hyper-CVAD regimen is effective in ALL and aggressive non-Hodgkin lymphomas (NHL) with increased CR rates and DFS rates. Between June 2002 and October 2006, 53 consecutive adult patients with newly diagnosed adult ALL were treated with Hyper-CVAD regimen for six to eight cycles. The alternating courses were given every 3-4 weeks or earlier if count recovery occurred. CR rates of 73.6% were achieved in 39 patients, the estimated 2-year survival rate was 82.9% and the estimated 2-year event-free survival (EFS) rate was 87.3%. Side effects were as expected, mostly attributed to myelosuppression. Analysis of prognostic factors suggested that some previously well-established poor prognostic factors such as the degree of leukocytosis and central nervous system (CNS) or testicular involvement were less important with this dose-intensive regimen. However, patients with mediastinal disease had lower CR rates (P<0.05), with the presence of hepatomegaly and t(9;22) abnormalities had poor survival (P<0.05). Compared with other established adult ALL regimens, Hyper-CVAD regimen was associated with significantly better CR rates, overall survival and EFS rates. The long-term follow-up results of Hyper-CVAD were favorable.

The negative prognostic impact of derivative 9 deletions in patients who received hydroxyurea treatment for chronic myelogenous leukemia in the chronic phase.

BACKGROUND: Chronic myeloid leukemia (CML) is characterized by the formation of the BCR/ABL fusion gene, as a consequence of the Philadelphia (Ph) translocation between chromosomes 9 and 22. This study was to investigate the incidence and prognostic significance of derivative chromosome 9 (der(9)) deletions in CML patients who received hydroxyurea treatment in the chronic phase. PATIENTS AND METHODS: Fluorescence in situ hybridization (FISH) analysis was used to assess the der(9) deletion status of 48 CML patients in blast crisis (CMLBC). RESULTS: Among the 48 CML patients, 8 (16.7%) showed der(9) deletions, and the deletions were also existent at diagnosis. The median duration of the chronic phase for patients with der(9) deletions was 18 (range 4-38) months compared to 48 (range 0-204) months for patients without deletions (p < 0.001). Der(9) deletions were not associated with increased karyotypic instability. There was no difference in the probability of the der(9) deletions between the cases having progressed to myeloid or lymphoid blast crisis. CONCLUSION: The results indicated that the FISH technique could effectively detect der(9) deletions. CML patients with der(9) deletions show more rapid progression and poorer prognosis, and the deletion status is a powerful prognostic factor.

Trisomy 22 as the sole abnormality is an important marker for the diagnosis of acute myeloid leukemia with inversion 16.

BACKGROUND: The inversion of chromosome 16 (inv(16) (p13q22)) and the related t(16;16)(p13;q22) are chromosomal aberrations observed in approximately 10% of de novo acute myeloid leukemia (AML), mostly classified as M4Eo subtype, and associated with a relatively favorable outcome. However, it is a cryptic rearrangement and often difficult to recognize in conventional cytogenetics (CC). Trisomy 22 is an uncommon karyotypic aberration in AML and is often associated with inv(16)(p13q22). The aim of this study was to explore the value of trisomy 22 in the diagnosis of AML with inv(16). PATIENTS AND METHODS: Dual-color interphase fluorescence in situ hybridization (FISH) was performed in 19 AML cases with trisomy 22 abnormality shown by R-banding CC. The probe was a two-color break-apart probe for CBFbeta on the centromeric side and the telomeric side. RESULTS: R-banding CC did not reveal inv(16) in any of the 19 AML with trisomy 22, but FISH analysis showed inv(16) in 11 cases and del(16)(q22) in 1 case. Among the 11 cases with inv(16), 9 showed trisomy 22 as the sole abnormality, 1 was complicated by trisomy 8, and 1 was del(16)(q22). CONCLUSION: This study further confirmed that trisomy 22 as the sole abnormality can be regarded as an important marker for inv(16) in AML.

Effect of low-dose cytarabine and aclarubicin in combination with granulocyte colony-stimulating factor priming (CAG regimen) on the outcome of elderly patients with acute myeloid leukemia.

The aim of this study was to evaluate the efficacy and toxicity of low-dose cytarabine and aclarubicin in combination with granulocyte colony-stimulating factor (G-CSF) protocol in elderly patients with acute myeloid leukemia (AML). A total of 50 elderly patients including 8 aged over 70 years were enrolled. All patients were treated with CAG regimen including low-dose cytarabine (10mg/m(2) every 12h, days 1-14), aclarubicin (10mg every day, days 1-8), and G-CSF (200 microg/m(2) every day, days 1-14) priming. The overall response rate was 72.0%, and 29 of 50 (58.0%) patients achieved complete remission, including 23 of 35 (65.8%) with previously untreated AML, 6 of 15 (40.0%) with refractory, relapsed or secondary AML, 4 of 8 (50.0%) aged over 70 years, 4 of 10 (40.0%) with unfavorable cytogenetic aberrations. The early death rate was 7.6%. The median overall survival was 14 months. Myelosuppression was mild to moderate, severe nonhematologic toxicity was not observed. Thus CAG priming regimen as the induction therapy is well tolerated and effective in elderly patients with AML.

[Analysis of complex chromosomal aberrations in patients with myelodysplastic syndromes using multiplex fluorescence in situ hybridization combined with whole chromosome painting].

OBJECTIVE: To explore the value of multiplex fluorescence in situ hybridization (M-FISH) in combination with whole chromosome painting (WCP) in the detection of complex chromosomal aberrations (CCAs) in myelodysplastic syndromes (MDS). METHODS: M-FISH was used in seven MDS patients with R-banding CCAs to refine the complex chromosomal rearrangements, and to identify cryptic translocations and characterization of marker chromosomes. Dual-color WCP procedures were further performed in 7 cases to confirm some rearrangements detected by M-FISH. RESULTS: M-FISH confirmed all results of R-banding. The composition and origin of 6 kinds of marker chromosomes, 9 kinds of chromosomes with additional material undetermined and 5 kinds of derivative chromosomes undefined by conventional cytogenetics (CC) were defined after M-FISH analysis; four kinds of cryptic translocations overlooked by CC were found on derivative chromosomes and previously normal appearing chromosomes. In addition, M-FISH revealed some nonrandom aberrations: aberrations involving chromosome 17 and -5/5q- were the two most frequent aberrations. Some misclassified and missed chromosomal aberrations by M-FISH were corrected by WCP. CONCLUSION: M-FISH is a powerful molecular cytogenetic tool in clarification of CCAs. Complementary WCP helps us to identify misclassified and missed chromosomal aberrations by M-FISH. CC in combination with molecular cytogenetic techniques, such as M-FISH and WCP, can unravel complex chromosomal aberrations more precisely.

[The investigation of JAK2 V617F point mutation in myeloproliferative disorders by allele-specific polymerase chain reaction in combination with sequence analysis].

OBJECTIVE: To study the JAK2 V617F point mutation in myeloproliferative disorders (MPD) and explore the clinical significance. METHODS: We used Allele-specific polymerase chain reaction (AS-PCR) in combination with sequence analysis to detect the mutation in genomic DNA of peripheral blood mononuclear cells from 20 chronic myelogenous leukemia (CML) patients, 23 polycythaemia vera (PV), 40 essential thrombocythaemia (ET), 8 idiopathic myelofibrosis (IMF), 3 hypereosinophilic syndrome (HES). RESULTS: JAK2 V617F was found in 38 (51.4%) of 74 BCR/ABL-negative MPD including 16 PV, 18 ET, 3 IMF and 1 HES patients. All positive samples and 10 negative samples identified by AS-PCR were confirmed by sequence analysis. Mutation-positive patients with ET had significantly increased hemoglobin, hematocrit, and neutrophil proportion than those without the mutation. CONCLUSION: JAK2 V617F mutation is the key molecular genetics feature of BCR/ABL-negative MPD. Detection of JAK2 V617F mutation will bring about a major impact to the diagnosis, classification and treatment of MPD.

Clinical significance of CSF3R, SRSF2 and SETBP1 mutations in chronic neutrophilic leukemia and chronic myelomonocytic leukemia.

Chronic neutrophilic leukemia (CNL) and chronic myelomonocytic leukemia (CMML) are rare hematologic neoplasms. We performed CSF3R, SRSF2 and SETBP1 mutational analyses in 10 CNL and 56 CMML patients. In this sample cohort, 80% of CNL patients harbored CSF3R mutations, of which the CSF3R T618I mutation was dominant. Mutations in CSF3R and SETBP1 were found in 7.1% and 5.3% CMML patients respectively, while 25% of CMML patients carried SRSF2 mutations. Strikingly, we identified that all of the CSF3R mutations detected in CMML patients were represented by a P733T mutation. The CSF3R P733T mutation represents a novel CSF3R mutation. In addition, none of the four CSF3R P733T mutated patients carried SRSF2 mutations [0/14 (0%) patients with combined CSF3R P733T and SRSF2 mutations vs. 4/42 (9.5%) with CSF3R P733T and wt SRSF2, P < 0.001]. Both mut SRSF2 and mut SETBP1 patients had shorter overall survival (OS) and progression-free survival (PFS) compared to patients with wt SRSF2 (P < 0.001 both) and wt SETBP1 (P < 0.001 and P = 0.02, respectively). While we found no significant differences in OS and PFS as a consequence of CSF3R mutation status, our work suggest that the CSF3R T618I mutation is a diagnostic marker with good specificity and sensitivity for CNL. In conclusion, our study highlights effective diagnostic and prognostic markers of CNL and CMML patients in the Chinese population.

Clinical Features and Prognosis Analysis of Hodgkin Lymphoma: A Multicenter Retrospective Study Over a Decade of Patients in China.

OBJECTIVE: There is little information available regarding Chinese patients with Hodgkin lymphoma (HL). We analyzed the clinical features, outcome, and prognostic factors of Chinese patients with HL, aiming to establish a new risk model for better risk-adapted therapeutic strategy. PATIENTS AND METHODS: Patients with newly diagnosed HL at 4 medical centers from January 2000 to August 2014 were recruited. RESULTS: A total of 150 patients were reviewed. The median age was 30 years (range, 15-91 years). At completion of initial therapy, 73.65% of patients achieved complete remission. The 5-year event-free survival (EFS) of the entire cohort was 61.1%, the overall survival was 84.7%, and the disease-free survival was 78.8%. B symptoms, extranodal involvement, and International Prognostic Score ≥ 3 remained as independent prognostic factors of EFS. Patients who failed to reach complete remission on interim positron emission tomography/computed tomography or computed tomography had a significantly worse outcome than those who did. A new risk model incorporating traditional risk factors and interim response stratified patients into 3 classes, with a 5-year EFS of 100%, 83.1%, and 33.1%, respectively (P < .0001). CONCLUSIONS: General clinical features were comparable with those of Western patients, whereas therapeutic outcomes were slightly inferior. The novel risk assessment model showed potential as a more powerful prognostic tool by identifying 3 subsets of patients with significantly distinct outcomes, which warrants further validations.

The investigation of mutation and single nucleotide polymorphism of receptor tyrosine kinases and downstream scaffold molecules in acute myeloid leukemia.

We investigate the role of mutations of receptor tyrosine kinases as well as their downstream scaffold molecules in leukemogenesis of acute myeloid leukemia (AML) in Chinese patients. Genes of interest included FLT3, PDGFRbeta, KDR, CSF2Rbeta, SOCS1, PIAS3 and SHIP. The coding sequence of these genes was analysed by the reverse transcription-polymerase chain reaction to search novel mutations. A novel mutation (A > T, Q1154L) of SHIP (1 of 192, 0.52%) was identified and another novel mutation (C > T, R685C) of PDGFRbeta (2 of 192, 1.04%). In addition, FLT3 mutations were seen in three of five patients with AML following myelodysplastic syndrome (60%) and 39 of 268 (14.6%) de novo AML patients (P < 0.05). No mutations were found in the coding sequence regions of KDR, CSF2Rbeta, SOCS1 or PIAS3.