Myelodysplastic syndromes: biology and treatment

[Clinical implication of minimal residue disease monitoring by WT1 gene detection and flow cytometry in myelodysplastic syndrome with allogeneic stem cell transplantation]

目的

探讨骨髓增生异常综合征（MDS）患者在接受异基因造血干细胞移植（allo-HSCT）后基于WT1基因及流式细胞术（FCM）监测微小残留病（MRD）的意义。

方法

分别采用实时定量聚合酶链反应（RQ-PCR）和8色FCM检测2011年2月至2015年10月于北京大学人民医院接受allo-HSCT的MDS患者移植前及移植后骨髓中WT1基因表达及异常免疫表型，并与临床结果进行相关分析。

结果

92例患者中，40例（48.2%）移植后WT1阳性，9例（10.8%）FCM阳性（FCM检测骨髓表型异常髓系幼稚细胞≥0.01%），27例（29.3%）患者MRDco阳性[连续2次WT1≥0.6%（间隔2周）或连续2次FCM阳性（间隔2周）或同一骨髓标本WT1≥0.6%且FCM阳性]。单因素分析显示移植后FCM阳性、MRDco阳性与复发相关（P<0.001，P=0.017）。FCM（+）、FCM（−）组移植后2年累积复发率（CIR）分别为66.7%、1.2%（P<0.001）；MRDco（+）、MRDco（−）组移植后2年CIR分别为23.0%、1.6%（P=0.004）。移植后WT1、FCM、MRDco预测复发的敏感性均为66.7%，特异性分别为59.0%、96.4%、74.7%。

结论

FCM和基于WT1/FCM的MRDco可作为MDS患者MRD监测的有效指标；基于MRDco标准进行干预可降低移植后复发率。

Clinical, hematological, and cytogenetic profile of adult myelodysplastic syndrome in a tertiary care center

BACKGROUND

Myelodysplastic syndrome (MDS), a disorder of clonal hematopoiesis, is an important clinical entity, but most of the studies available are conducted among the Western population. Its etiological factors and clinicohematological profile in the Indian population are quite diverse. The information regarding its prognostic factors and cytogenetics is very scarce.

OBJECTIVES

(1) To assess the clinicohematological profile, cytogenetics, prognostic factors, and outcome of MDS and (2) to study its progression to acute myeloid leukemia (AML) in the selected patients over the study period.

METHODS

A prospective observational study was performed with patients from Department of Medicine and Hematology, Government Medical College, Kozhikode, who were diagnosed with MDS within the study period (from 1 January 2014 to 31 July 2015). Secondary causes of dysplasia were excluded. In possible cases, the international prognostic scoring system was followed. These patients were followed up for an additional 6 months to assess the progression of MDS to AML based on symptoms, signs, hemogram, or repeat peripheral smear/bone marrow studies.

RESULTS

Of the 60 patients, 73% were aged >60 years. Disease was common in males, with a male:female ratio of 7:3. Thirty-five percent of the patients were working in agricultural and allied fields and had pesticide exposure. Patients with prior radiation exposure had significant association with adverse outcome. Fatigue was the prominent symptom and was reported by 90% of the patients. Blasts were >5% in peripheral smear; bone marrow cytopenia and dysplasia at the time of diagnosis had significant association with risk of transforming to AML. Refractory anemia (RA), observed in 22 patients, was the most common type of MDS. Most of the patients with RA with excess blasts type-1 and RA with excess blasts type-2 transformed to AML, and the association was statistically significant. Deletion of short arm of fifth chromosome (5q deletion) was detected in 11 patients. All of them showed good response to treatment with lenalidomide and had a favorable outcome.

CONCLUSION

This study highlights the various etiological factors, and the clinical profile of MDS seen in the Indian population. Cytogenetic analysis and application of the international prognostic scoring system has a significant bearing on the outcome, as exemplified by the response to lenalidomide in patients with 5q deletion. This study also indicates that proper diagnostic and prognostic assessment is necessary to institute appropriate therapeutic options.

Arsenic trioxide and triptolide synergistically induce apoptosis in the SKM‑1 human myelodysplastic syndrome cell line

Although certain combination therapies comprising arsenic trioxide (As₂O₃) with other agents exist for the treatment of several types of human cancer, few As₂O₃ combination therapies are clinically effective for myelodysplastic syndromes (MDS). Triptolide (TL) may be an effective therapeutic agent for the treatment of MDS. However, to date, there is no combination therapy for MDS with As₂O₃ and TL. Therefore, the aim of the present study was to investigate this combination therapy on the apoptosis of MDS SKM-1 cells. The MDS SKM-1 cells were treated with As₂O₃, TL or the two in combination at various concentrations, or were mock-treated. Cell viability, cell apoptosis, levels of reactive oxygen species (ROS) and the expression of the cell apoptosis-associated genes, B cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax) and caspase-3, were determined using an MTT assay, flow cytometric analysis of annexin V-fluorescein isothiocyanate/propidium iodide double-stained cells, flow cytometic analysis of intracellular 2′,7′-dichlorodihydrofluorescein diacetate fluorescence and reverse transcription-quantitative polymerase chain reaction analysis, respectively. Combination index (CI) analysis was performed to determine whether effects were synergistic (CI<1). The combination treatment was found to synergistically inhibit MDS SKM-1 cell growth, induce cell apoptosis, increase ROS levels, upregulate the expression levels of Bax and caspase-3, and downregulate the mRNA expression of Bcl-2. In conclusion, the combination treatment of As₂O₃ and TL synergistically induced apoptosis in the MDS SKM-1 cells.

The Differencies in Adult and Pediatric Myelodysplastic Syndrome: A Review

Myelodysplastic syndrome (MDS) represent very heterogenous group of clonal stem cell bone marrow disorders with ineffective haematopoesis leading to cytopenias in peripheral blood and increased risk of blastic transformation and evolution of acute myeloid leukemia. MDS is a disease of older age mostly, in children it seems to be very rare. There are several significant morphological, cytogenetic and prognostic differencies of the disease in adults and in children. Adult MDS patients most commonly manifest with symptoms of anemia, bleeding and infection are uncommon. In childhood, MDS manifests predominantly by neutropenia and thrombocytopenia. In addition, some pediatric MDS patients present also with constitutional disease’s signs and symptoms. Early and correct diagnosis in both age groups is essential for the choice of appropriate therapy and also for next life of patients. However, the diagnosis of MDS is challenging, complex and requiring close correlation of clinical symptoms, laboratory parameters and standardized examination of BM biopsies. The authors present an overview focused on biology of MDS in adults and children, on the differences in the incidence, clinical presentation and treatment. They summarize the possibilities and limits of histopathological diagnosis and differential diagnosis of the disease in different age groups. A major problem in the morphological diagnosis of MDS remains the determination, whether the myelodysplasia is due to clonal disorder. It might result also from some other factors, as significant dysplasia can also occur in reactive conditions, and vice versa, only discrete dysplasia is sometimes observed in MDS patients. Although histomorphological and immunohistochemical analysis of BM biopsy is invasive and time-consuming examination, it has its value in the diagnosis, differential diagnosis and evaluation of therapeutic effect.

Occupational Exposure and Health Impairments of Formaldehyde on Employees of a Wood Industry

Background: Occupational exposure to formaldehyde may decrease white blood cell counts and change blood concentration. In this study, the influences of occupational exposure to formaldehyde on the number of white blood cells and blood concentrations were studied.

Methods: This case-control study was conducted in June of 2012 at North Wood Factory, Golestan Province, Iran. The US-NIOSH method No. 2541 was used to determine the occupational exposure of 30 workers of the production line (case group) and 30 administrative staffs (control group) to formalde­hyde. The number of white blood cells and blood concentration were determined using the normal blood count method and related indices. Demographic features as well as the symptoms of being exposed to formaldehyde were collected using a standard questionnaire.

Results: The occupational exposure of case group ranged from 0.50 ppm to 1.52 ppm. The prevalence of all studied symptoms from formaldehyde exposure in workers (2<median<5; range 1 to 5) was signifi­cantly different (P<0.001) towards the administrative staffs (median 1; range 1 to 4). The number of white blood cells in production line workers was not significantly different from those in administra­tive staff. The average blood concentration in the case group was significantly different from the con­trol group (mean difference= 0.9 [95% CI: 0.40-1.39];P=0.007).

Conclusion: Occupational exposure to formaldehyde changed the blood concentration of the studied workers but did not change the number of their white blood cells.

Genome sequencing in myelodysplastic syndromes: can molecular mutations predict benefit from hypomethylating agent therapy?

Evaluation of: Bejar R, Lord A, Stevenson K, et al. TET2 mutations predict response to hypomethylating agents in myelodysplastic syndrome patients. Blood 2014 Oct 23;124(17):2705-12. Patients with myelodysplastic syndromes (MDS) have clinically variable courses even within the same prognostic subgroups. Although hypomethylating agents (HMAs) have been shown to improve outcomes in patients with high-risk MDS, many patients do not derive benefit. There is an urgent clinical need to identify patients with low probability of benefiting from HMAs but no reliable clinical predictors or biomarkers have been discovered to date. Although some recurrent molecular mutations in MDS carry independent prognostic value, their ability to predict benefit from HMAs is not clear. Here, we discuss an important article in which sequencing from samples of 213 patients identified recurrent mutations associated with response to HMAs. Although an important step in the right direction, the clinical implications of these findings are far from optimal and identification of biomarkers that can reliably predict benefit from HMAs and other therapies in patients with MDS remains a top clinical and a research priority.

BCOR and BCORL1 mutations in myelodysplastic syndromes and related disorders

Patients with low-risk myelodysplastic syndromes (MDS) that rapidly progress to acute myeloid leukemia (AML) remain a challenge in disease management. Using whole-exome sequencing of an MDS patient, we identified a somatic mutation in the BCOR gene also mutated in AML. Sequencing of BCOR and related BCORL1 genes in a cohort of 354 MDS patients identified 4.2% and 0.8% of mutations respectively. BCOR mutations were associated with RUNX1 (P = .002) and DNMT3A mutations (P = .015). BCOR is also mutated in chronic myelomonocytic leukemia patients (7.4%) and BCORL1 in AML patients with myelodysplasia-related changes (9.1%). Using deep sequencing, we show that BCOR mutations arise after mutations affecting genes involved in splicing machinery or epigenetic regulation. In univariate analysis, BCOR mutations were associated with poor prognosis in MDS (overall survival [OS]: P = .013; cumulative incidence of AML transformation: P = .005). Multivariate analysis including age, International Prognostic Scoring System, transfusion dependency, and mutational status confirmed a significant inferior OS to patients with a BCOR mutation (hazard ratio, 3.3; 95% confidence interval, 1.4-8.1; P = .008). These data suggest that BCOR mutations define the clinical course rather than disease initiation. Despite infrequent mutations, BCOR analyses should be considered in risk stratification.

Prospective phase II Study on 5-days azacitidine for treatment of symptomatic and/or erythropoietin unresponsive patients with low/INT-1-risk myelodysplastic syndromes

PURPOSE

This phase II prospective study aimed to evaluate the efficacy and safety of 5-days azacytidine (5d-AZA) in patients with low-risk myelodysplastic syndromes (MDS). Second, single-nucleotide polymorphism (SNP) genetic profile and phosphoinositide-phospholipase C (PI-PLC) β1 levels were studied to evaluate possible biologic markers able to predict the hematologic response.

EXPERIMENTAL DESIGN

The study tested a lower intensity schedule of azacytidine. The treatment plan consisted of 75 mg/sqm/d subcutaneous administered for 5 days every 28 days, for a total of 8 cycles.

RESULTS

Thirty-two patients were enrolled in the study. The overall response rate was 47% (15 of 32) on intention-to-treat and 58% (15 of 26) for patients completing the treatment program. In this latter group, 5 (19%) achieved complete remission (CR) and 10 (38%) had hematologic improvement, according to the International Working Group (IWG) criteria. Three patients have maintained their hematologic improvement after 37, 34, and 33 months without other treatments. Moreover, 21 and 2 of 26 cases completing 8 cycles were transfusion-dependent for red blood cells and platelets at baseline, respectively. Of these, 7 (33%) and 2 (100%) became transfusion-independent at the end of the treatment program, respectively. Grade 3-4 neutropenia occurred in 28% of patients and 4 patients died early due to infections or hemorrhage. SNP results were not significantly correlated to the clinical outcome, whereas PI-PLCβ1 level anticipated either positive or negative clinical responses.

CONCLUSIONS

5d-AZA is safe and effective in a proportion of patients with low-risk MDS. PI-PLCβ1 gene expression is a reliable and dynamic marker of response that can be useful to optimize azacytidine therapy.

A randomized, double-blind, placebo-controlled phase 2 study evaluating the efficacy and safety of romiplostim treatment of patients with low or intermediate-1 risk myelodysplastic syndrome receiving lenalidomide

Background

Lenalidomide treatment in myelodysplastic syndrome (MDS) may lead to thrombocytopenia and dose reductions/delays. This study evaluated the safety and tolerability of the thrombopoietin mimetic romiplostim and its effects on the incidence of clinically significant thrombocytopenic events (CSTEs) in lower risk MDS patients receiving lenalidomide.

Methods

Patients were assigned to weekly placebo (n = 12) or romiplostim 500 μg (n = 14) or 750 μg (n = 13) for four 28-day lenalidomide cycles.

Results

The treatment groups were generally similar with respect to baseline disease characteristics. Del(5q) abnormalities were noted in 1 (8%) patient in the placebo group, 3 (21%) in the romiplostim 500 μg group, and two (15%) in the 750 μg group. CSTEs were noted in 8 (67%) patients in the placebo group, 4 (29%) in the romiplostim 500 μg group, and 8 (62%) in the romiplostim 750 μg group. Throughout the study, median platelet counts trended lower in placebo-treated than in romiplostim-treated patients. Thrombocytopenia-related adjustments in lenalidomide occurred in 6 (50%) patients in the placebo group, 5 (36%) in the romiplostim 500 μg group, and 2 (15%) in the 750 μg group. Although the percentages of patients who received platelet transfusions were similar across treatment groups, there was a trend toward lower numbers of transfusions in both romiplostim groups during each treatment cycle. There were two serious treatment-related adverse events during the treatment period (cerebrovascular accident, placebo; worsening thrombocytopenia, romiplostim 500 μg). Two patients (romiplostim 500 and 750 μg, respectively) had an increase in bone marrow blasts to >20% during treatment, but had no post-treatment biopsy to confirm or exclude the diagnosis of progression to AML.

Conclusions

These data suggest that romiplostim administered to MDS patients during lenalidomide treatment may decrease the frequency of dose reductions/delays due to thrombocytopenia. Additional study is needed to confirm the results of this preliminary trial.

Trial registration

ClinicalTrials.gov NCT00418665

A randomized controlled trial of romiplostim in patients with low- or intermediate-risk myelodysplastic syndrome receiving decitabine

Patients with myelodysplastic syndrome (MDS) receiving hypomethylating agents commonly develop thrombocytopenia. This double-blind study evaluated the efficacy and safety of romiplostim, a peptibody protein that increases platelets, in patients with MDS receiving decitabine. Patients received romiplostim 750 μg (n = 15) or placebo (n = 14) and decitabine. Median platelet counts at the beginning of each decitabine cycle trended lower in placebo-treated than in romiplostim-treated patients. Bleeding events occurred in 43% of placebo-treated and 27% of romiplostim-treated patients, and platelet transfusions were administered to 57% of placebo-treated and 47% of romiplostim-treated patients. Overall clinical therapeutic response was achieved by 21% of placebo-treated and 33% of romiplostim-treated patients. Treatment was generally well tolerated. Progression to acute myeloid leukemia (AML) occurred in one patient per group. Adding romiplostim to decitabine treatment is well tolerated and may be beneficial, as indicated by trends toward higher platelet counts at the beginning of each treatment cycle and lower platelet transfusion rates and percentages of patients with bleeding events.

Localization of the NRAS:BCL-2 complex determines anti-apoptotic features associated with progressive disease in myelodysplastic syndromes

We have previously demonstrated that two prognostic features of myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML), mutant NRAS and over-expressing BCL-2, cooperate physically and functionally in vivo. Screening of MDS patient bone marrow (BM) identified NRAS:BCL-2 co-localization in 64% cases, correlating with percentage BM blasts, apoptotic features and disease status (p<0.0001). Localization of the complex at the plasma membrane or the mitochondria correlated with disease and apoptosis features in MDS patients, whilst caspase-9 mediated mechanism was elucidated in vivo and in vitro. The intensity and localization of the RAS:BCL-2 complex merits further evaluation as a novel biomarker of MDS.

Frequency and prognostic impact of mutations in SRSF2, U2AF1, and ZRSR2 in patients with myelodysplastic syndromes

Mutations in genes of the splicing machinery have been described recently in myelodysplastic syndromes (MDS). In the present study, we examined a cohort of 193 MDS patients for mutations in SRSF2, U2AF1 (synonym U2AF35), ZRSR2, and, as described previously, SF3B1, in the context of other molecular markers, including mutations in ASXL1, RUNX1, NRAS, TP53, IDH1, IDH2, NPM1, and DNMT3A. Mutations in SRSF2, U2AF1, ZRSR2, and SF3B1 were found in 24 (12.4%), 14 (7.3%), 6 (3.1%), and 28 (14.5%) patients, respectively, corresponding to a total of 67 of 193 MDS patients (34.7%). SRSF2 mutations were associated with RUNX1 (P < .001) and IDH1 (P = .013) mutations, whereas U2AF1 mutations were associated with ASXL1 (P = .005) and DNMT3A (P = .004) mutations. In univariate analysis, mutated SRSF2 predicted shorter overall survival and more frequent acute myeloid leukemia progression compared with wild-type SRSF2, whereas mutated U2AF1, ZRSR2, and SF3B1 had no impact on patient outcome. In multivariate analysis, SRSF2 remained an independent poor risk marker for overall survival (hazard ratio = 2.3; 95% confidence interval, 1.28-4.13; P = .017) and acute myeloid leukemia progression (hazard ratio = 2.83; 95% confidence interval, 1.31-6.12; P = .008). These results show a negative prognostic impact of SRSF2 mutations in MDS. SRSF2 mutations may become useful for clinical risk stratification and treatment decisions in the future.

A new recurrent chromosomal translocation t(3;11)(q13;q14) in myelodysplastic syndromes associated with overexpression of the ILDR1 gene

Myelodysplastic syndromes (MDS) are a heterogeneous group of diseases characterized by ineffective hematopoiesis and an increased risk of evolution to acute myeloid leukemia (AML). In this study, the combination of conventional cytogenetic, FISH studies and molecular techniques allowed us to unveil a novel recurrent t(3;11)(q13;q14) causing the overexpression of the immunoglobulin-like domain-containing receptor (ILDR1) gene. The analysis of gene expression was extended to Refractory Anemia (RA) and Refractory Anemia with excess blasts (RAEB) cases revealing ILDR1 overexpression in 36% of RAEB subgroup. The biological implications of the ILDR1 overexpression in MDS pathogenesis and its potential prognostic significance should be further investigated.

Mutations affecting mRNA splicing define distinct clinical phenotypes and correlate with patient outcome in myelodysplastic syndromes

A cohort of MDS patients was examined for mutations affecting 4 splice genes (SF3B1, SRSF2, ZRSR2, and U2AF35) and evaluated in the context of clinical and molecular markers. Splice gene mutations were detected in 95 of 221 patients. These mutations were mutually exclusive and less likely to occur in patients with complex cytogenetics or TP53 mutations. SF3B1(mut) patients presented with lower hemoglobin levels, increased WBC and platelet counts, and were more likely to have DNMT3A mutations. SRSF2(mut) patients clustered in RAEB-1 and RAEB-2 subtypes and exhibited pronounced thrombocytopenias. ZRSR2(mut) patients clustered in International Prognostic Scoring System intermediate-1 and intermediate-2 risk groups, had higher percentages of bone marrow blasts, and more often displayed isolated neutropenias. SRSF2 and ZRSR2 mutations were more common in TET2(mut) patients. U2AF35(mut) patients had an increased prevalence of chromosome 20 deletions and ASXL1 mutations. Multivariate analysis revealed an inferior overall survival and a higher AML transformation rate for the genotype ZRSR2(mut)/TET2(wt) (overall survival: hazard ratio = 3.3; 95% CI, 1.4-7.7; P = .006; AML transformation: hazard ratio = 3.6; 95% CI, 2-4.2; P = .026). Our results demonstrate that splice gene mutations are among the most frequent molecular aberrations in myelodysplastic syndrome, define distinct clinical phenotypes, and show preferential associations with mutations targeting transcriptional regulation.

Prognostic significance of ASXL1 mutations in patients with myelodysplastic syndromes

PURPOSE

To study the incidence and prognostic impact of mutations in Additional sex comb-like 1 (ASXL1) in a large cohort of patients with myelodysplastic syndrome (MDS).

PATIENTS, MATERIALS, AND METHODS

Overall, 193 patients with MDS and 65 healthy volunteers were examined for ASXL1 mutations by direct sequencing and for expression levels of ASXL1. The prognostic impact of ASXL1 mutation and expression levels was evaluated in the context of other clinical and molecular prognostic markers.

RESULTS

Mutations in ASXL1 occurred with a frequency of 20.7% in MDS (n = 40 of 193) with 70% (n = 28) of mutations being frameshift mutations and 30% (n = 12) being heterozygous point mutations leading to translational changes. ASXL1 mutations were correlated with an intermediate-risk karyotype (P = .002) but not with other clinical parameters. The presence of ASXL1 mutations was associated with a shorter overall survival for frameshift and point mutations combined (hazard ratio [HR], 1.744; 95% CI, 1.08 to 2.82; P = .024) and for frameshift mutations only (HR, 2.06; 95% CI, 1.21 to 3.50; P = .008). ASXL1 frameshift mutations were associated with a reduced time to progression of acute myeloid leukemia (AML; HR 2.35; 95% CI, 1.17 to 4.74; P = .017). In multivariate analysis, when considering karyotype, transfusion dependence, and IDH1 mutation status, ASXL1 frameshift mutations remained an independent prognostic marker in MDS (overall survival: HR, 1.85; 95% CI, 1.03 to 3.34; P = .040; time to AML progression: HR, 2.39; 95% CI, 1.12 to 5.09; P = .024).

CONCLUSION

These results suggest that ASXL1 mutations are frequent molecular aberrations in MDS that predict an adverse prognostic outcome. Screening of patients for ASXL1 mutations might be useful for clinical risk stratification and treatment decisions in the future.

Darbepoetin alfa for anemia in patients with low or intermediate-1 risk myelodysplastic syndromes and positive predictive factors of response

BACKGROUND

Current guidelines support the use of erythropoiesis-stimulating agents for the treatment of anemia associated with low-risk myelodysplastic syndromes (MDS).

DESIGN AND METHODS

Single-arm, open-label, multi-center, phase 2 trial that evaluated the efficacy and safety of darbepoetin alfa (DA) in patients with low or intermediate-risk MDS, hemoglobin <100 g/L, erythropoietin (EPO) levels <500 IU/L and transfusion requirements <2 units/month over the preceding 2 months. Erythroid response (major [MaR] or minor [MiR]) and fatigue (Functional Assessment of Cancer Therapy-Fatigue [FACT-F]) were evaluated at 8, 16 and 24 weeks. DA was initiated at 300 μg weekly. For patients who did not achieve MaR by 8 weeks, filgrastim 300 μg weekly was added.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov identifier: NCT01039350.

RESULTS

Forty-four patients (72.7% transfusion independent) were included. Median age was 76.0 years (range 41.3-92.4), 54.5% were male, and 90.9% presented ECOG Status (0-1). Eighteen patients received filgrastim. An erythroid response was achieved by 31 of 44 patients (70.5%) at week 8 (47.7% MaR, 22.7% MiR), 31 of 44 patients (70.5%) at week 16 (61.4% MaR, 9.1% MiR), and 32 of 44 patients (72.7%) at week 24 (61.3% MaR, 11.4% MiR). Mean (95% CI) change in FACT-F at week 24 was 3.61 (0.72 to 6.51). Baseline EPO levels <100 IU/L were a predictive factor of response. DA was well tolerated. Four mild (two iron deficiencies, flu syndrome and headache) and one fatal (thromboembolic event) adverse events were considered related to darbepoetin alfa.

CONCLUSIONS

A fixed dose of 300 μg of darbepoetin alfa weekly (with or without filgrastim) seems to be an effective and safe treatment for anemic patients with low or intermediate-risk MDS, low transfusion burden and EPO levels <500 IU/L. Results may not be extrapolable to unselected MDS patients.

Aberrant microRNA expression pattern in myelodysplastic bone marrow cells

The microRNA/miR system might contribute to deregulation of cell homeostasis/disease phenotype. This is the first approach to generate an expression profile of 365 microRNAs in myelodysplastic syndromes (MDS) with normal karyotype (n=12) and distinct cytogenetic aberrations (n=12). In MDS-del(5q), a series of microRNAs not in the 5q-region was increased. MicroRNAs encoded on chromosomes 5, 7 and 8 were not differentially expressed in MDS with del(5q), -7 or +8. Evaluation in a larger cohort could confirm the up-regulation of the miR-1 in MDS. These findings provide evidence that MDS-haematopoiesis is distinct in its microRNA-expression pattern from non-neoplastic cells.

Azacitidine: a review of its use in higher-risk myelodysplastic syndromes/acute myeloid leukaemia

Azacitidine (Vidaza) is a pyrimidine nucleoside analogue of cytidine. Subcutaneous azacitidine was recently approved in the EU for the treatment of adults who are not eligible for haematopoietic stem cell transplantation and who have intermediate-2-risk or high-risk myelodysplastic syndromes (MDS) [according to International Prognostic Scoring System (IPSS) criteria], chronic myelomonocytic leukaemia (CMML) with 10-29% marrow blasts without myeloproliferative disorder, or acute myeloid leukaemia (AML) with 20-30% blasts and multilineage dysplasia (according to the WHO classification). Subcutaneous azacitidine is the only drug shown to significantly prolong survival in patients with higher-risk MDS or WHO-defined AML, compared with conventional care (i.e. best supportive care, low-dose cytarabine or intensive chemotherapy). In addition, azacitidine is associated with a lower risk of AML progression and higher rates of complete remission, partial remission, haematological improvement and red blood cell (RBC) transfusion independence. Azacitidine has an acceptable tolerability profile; peripheral cytopenias are the most commonly occurring adverse event. Thus, azacitidine is a valuable option for the first-line treatment of patients with higher-risk MDS/AML.

Deregulated gene expression pathways in myelodysplastic syndrome hematopoietic stem cells

To gain insight into the molecular pathogenesis of the myelodysplastic syndromes (MDS), we performed global gene expression profiling and pathway analysis on the hematopoietic stem cells (HSC) of 183 MDS patients as compared with the HSC of 17 healthy controls. The most significantly deregulated pathways in MDS include interferon signaling, thrombopoietin signaling and the Wnt pathways. Among the most significantly deregulated gene pathways in early MDS are immunodeficiency, apoptosis and chemokine signaling, whereas advanced MDS is characterized by deregulation of DNA damage response and checkpoint pathways. We have identified distinct gene expression profiles and deregulated gene pathways in patients with del(5q), trisomy 8 or -7/del(7q). Patients with trisomy 8 are characterized by deregulation of pathways involved in the immune response, patients with -7/del(7q) by pathways involved in cell survival, whereas patients with del(5q) show deregulation of integrin signaling and cell cycle regulation pathways. This is the first study to determine deregulated gene pathways and ontology groups in the HSC of a large group of MDS patients. The deregulated pathways identified are likely to be critical to the MDS HSC phenotype and give new insights into the molecular pathogenesis of this disorder, thereby providing new targets for therapeutic intervention.

Does cytogenetic evolution have any prognostic relevance in myelodysplastic syndromes? A study on 153 patients from a single institution

The present study was designed to establish the incidence of cytogenetic evolution (CE), defined as the acquisition of chromosomal defects during the course of MDS, in order to correlate it with the WHO classification and IPSS score, and to assess its impact on overall survival (OS) and risk of MDS/AML evolution (progression-free interval, PFI) by means of Cox models for time-dependent covariates. Adjustments for known risk factors were achieved by performing a bivariable analysis. The study was carried out in 153 MDS patients who were followed for a median period of 45.2 months. Disease progression occurred in 42.4% of patients after a 65.2-month median PFI, while CE occurred in 30.7% of patients. Our study shows that (1) CE was more common in advanced than in early MDS, and advanced MDS presented secondary chromosomal defects distinct from those of early MDS; (2) CE significantly affected OS and PFI independently of other prognostic variables; (3) del(7)(q31q34) was the only secondary chromosomal defect which significantly affected PFI; trisomy 8 had only a moderate influence.

Testing the NKT cell hypothesis in lenalidomide-treated myelodysplastic syndrome patients

Myelodysplastic syndrome (MDS) comprises a group of clonal bone marrow disorders characterized by ineffective hematopoiesis and increased predisposition to acute myeloid leukemia. The causes of MDS remain poorly defined, but several studies have reported the NKT cell compartment of patients with MDS is deficient in number and functionally defective. In support of a central role for NKT cells, a pilot clinical study reported that lenalidomide (an approved treatment for MDS) increased NKT cell numbers in patients with MDS, and several in vitro studies showed lenalidomide specifically promoted NKT cell proliferation and cytokine production. We tested this in a much larger study and confirm a moderate in vitro augmentation of some NKT cell functions by lenalidomide, but find no impact on the NKT cell compartment of patients treated with lenalidomide, despite a consistently positive clinical response. We further show that the frequency and cytokine production of NKT cells is normal in patients with MDS before treatment and remains stable throughout 10 months of lenalidomide therapy. Collectively, our data challenge the concept that NKT cell defects contribute to the development of MDS, and show that a clinical response to lenalidomide is not dependent on modulation of NKT cell frequency or function.

Occupational exposure to formaldehyde, hematotoxicity, and leukemia-specific chromosome changes in cultured myeloid progenitor cells

There are concerns about the health effects of formaldehyde exposure, including carcinogenicity, in light of elevated indoor air levels in new homes and occupational exposures experienced by workers in health care, embalming, manufacturing, and other industries. Epidemiologic studies suggest that formaldehyde exposure is associated with an increased risk of leukemia. However, the biological plausibility of these findings has been questioned because limited information is available on the ability of formaldehyde to disrupt hematopoietic function. Our objective was to determine if formaldehyde exposure disrupts hematopoietic function and produces leukemia-related chromosome changes in exposed humans. We examined the ability of formaldehyde to disrupt hematopoiesis in a study of 94 workers in China (43 exposed to formaldehyde and 51 frequency-matched controls) by measuring complete blood counts and peripheral stem/progenitor cell colony formation. Further, myeloid progenitor cells, the target for leukemogenesis, were cultured from the workers to quantify the level of leukemia-specific chromosome changes, including monosomy 7 and trisomy 8, in metaphase spreads of these cells. Among exposed workers, peripheral blood cell counts were significantly lowered in a manner consistent with toxic effects on the bone marrow and leukemia-specific chromosome changes were significantly elevated in myeloid blood progenitor cells. These findings suggest that formaldehyde exposure can have an adverse effect on the hematopoietic system and that leukemia induction by formaldehyde is biologically plausible, which heightens concerns about its leukemogenic potential from occupational and environmental exposures.

The clinical utility of lenalidomide in multiple myeloma and myelodysplastic syndromes

PURPOSE

the pharmacology, pharmacokinetics, pharmacodynamics, clinical utility, adverse effects, dosage, and cost of lenalidomide are reviewed.

SUMMARY

lenalidomide is a thalidomide analogue approved for treatment of myelodysplastic syndromes (MDS) associated with a cytogenetic 5q deletion. In combination with dexamethasone, lenalidomide has been approved by the FDA in the United States for the treatment of relapsed or refractory multiple myeloma, and is sometimes used for induction therapy. Although the precise mechanism of action of lenalidomide remains unknown, it does exhibit antineoplastic and immunomodulatory properties. Lenalidomide is quickly absorbed after oral administration and is renally eliminated. In patients with myelodysplatic syndromes, lenalidomide reduces the need for transfusion. In patients with refractory or relapsed multiple myeloma, lenalidomide in combination with dexamethasone demonstrated a significantly longer time to tumor progression compared to placebo plus dexamethasone. Lenalidomide in combination with dexamethasone also elicited an objective response from patients with newly diagnosed symptomatic multiple myeloma. Treatment with lenalidomide was associated with neutropenia, thrombocytopenia, constipation, pruritus, and fatigue. Due to the teratogenic nature of thalidomide, lenalidomide must be obtained through a restrictive distribution program. The initial daily dosing of lenalidomide is 10 mg for MDS with a 5q deletion and 25 mg for relapsed or refractory multiple myeloma. Dose modifications are required for renal impairment and grade 3-4 adverse events.

CONCLUSION

lenalidomide is an effective agent for the treatment of MDS with a 5q deletion and relapsed or refractory multiple myeloma.