[Myelodysplastic syndrome]

Myelodysplastic syndrome is a hematopoietic stem cell disorder characterized by ineffective hematopoiesis and leukemic progression. Accumulation of various kinds of genetic alterations in oncogene and tumor suppressor gene develops and accelerates the disease. Recently, alpha-catenin gene has been identified as a candidate gene in the 5q- anomaly. Diagnostic criteria have been updated by Valent et al. WHO classification has become popular and WHO classification-based prognostic scoring system will be employed to evaluate prognosis. In our country, clinical studies on vitamin K2+D3 and cyclosporine A were conducted in low-risk patients, and their efficacy and safety have been reported. In US, molecular-targeting therapy with lenalidomide or demethylase is approved by FDA.

Histone deacetylase inhibitors trichostatin A and valproic acid circumvent apoptosis in human leukemic cells expressing the RUNX1 chimera

Disturbance of the normal functions of wild-type RUNX1 resulting from chromosomal translocations or gene mutations is one of the major molecular mechanisms in human leukemogenesis. RUNX1-related chimeras generated by the chromosomal translocations repress transcriptional activity of wild-type RUNX1 by recruiting the co-repressor/histone deacetylase complex. Thus, histone deacetylase inhibitors are expected to restore normal functions of wild-type RUNX1 and thereby affect the growth and differentiation ability of leukemic cells expressing the chimera. We investigated the in vitro effects of histone deacetylase inhibitors, trichostatin A and valproic acid, on human leukemic cell lines such as SKNO-1 and Kasumi-1 expressing RUNX1/ETO, Reh expressing TEL/RUNX1 and SKH-1 co-expressing RUNX1/EVI1 and BCR/ABL. We also employed K562 cells expressing BCR/ABL without such a chimera as a control. Treatment with each inhibitor increased acetylated histone 4 in all of these cell lines. Interestingly, proliferation of SKNO-1, Kasumi-1, SKH-1 and Reh cells was significantly suppressed after 3-day culture with trichostatin A or valproic acid, when compared to that of K562 cells. We observed cell cycle arrest and apoptotic induction in the RUNX1 chimera-expressing cells by the propidium iodide staining. Up- and downregulation of cell cycle regulator genes appeared to be the molecular basis for the former, and activation of both extrinsic and intrinsic apoptotic caspases for the latter. We propose histone deacetylase inhibitors to be an attractive choice in the molecular targeting therapy of RUNX1-related leukemia.

A prospective study of cyclosporine A treatment of patients with low-risk myelodysplastic syndrome: presence of CD55(-)CD59(-) blood cells predicts platelet response

Although immunosuppressive therapy using antithymocyte globulin or cyclosporine A (CSA) is effective in selected patients with low-risk myelodysplastic syndrome, the response rates reported so far are inconsistent, and the indication of immunosuppressive therapy for myelodysplastic syndrome has not been clearly defined. We treated 20 myelodysplastic syndrome patients (17 refractory anemia cases [RA], 2 RA with excess blasts, and one RA with ringed sideroblasts) with 4 mg/kg per day of CSA for 24 weeks. Among the 19 patients evaluated, 10 showed hematologic improvement; 8 patients showed an erythroid response, 6 showed a platelet response, and one showed a neutrophil response. Most patients with hematologic improvement continued CSA thereafter, and the progressive response was observed until the latest follow-up (median, 30 months). Most toxicities associated with CSA usage were manageable, and no patient had developed acute leukemia up to this point. Short duration of illness, refractory anemia with minimal dysplasia determined by bone marrow morphology, and the presence of paroxysmal nocturnal hemoglobinuria-type cells were significantly associated with the platelet response. A minority of RA patients who did not possess such predictive variables achieved an isolated erythroid response. In conclusion, CSA may be a therapeutic option for patients with RA who do not have adverse prognostic factors.

RUNX1/EVI1, which blocks myeloid differentiation, inhibits CCAAT-enhancer binding protein alpha function

The RUNX1/EVI1 chimeric transcription factor produced by t(3;21) causes leukemic transformation in hematopoietic stem cell tumors, possibly through a differentiation block of malignant myeloid progenitors. A dominant negative effect over wild-type RUNX1 has been shown to constitute one of the underlying molecular mechanisms. We introduced RUNX1/EVI1 cDNA into LG-3 cells that differentiate along the myeloid lineage upon exposure to granulocyte colony stimulating factor, and confirmed that RUNX1/EVI1 suppressed the differentiation. To further investigate the molecular mechanisms of RUNX1/EVI1-mediated differentiation block, we analyzed RUNX1/EVI1's effect on the functions of CCAAT-enhancer binding protein alpha (C/EBPalpha), a key transcriptional regulator that induces granulocytic differentiation. RUNX1/EVI1 was found to associate with C/EBPalpha. By using a reporter assay with the CEBPA promoter, we observed a dominant negative effect of RUNX1/EVI1 over C/EBPalpha-mediated transcriptional activation via the carboxyl terminal-binding protein (CtBP)-binding site in the EVI1 portion. In a gel-shift assay, RUNX1/EVI1 downregulated the DNA-binding activity of C/EBPalpha. Therefore, recruitment of histone deacetylase via CtBP and disruption of DNA binding could be likely scenarios for the RUNX1/EVI1-induced dominant repression on C/EBPalpha. Importantly, coexpression of C/EBPalpha restored the differentiation ability of the RUNX1/EVI1-expressing LG-3 cells. All of these data argue that inhibition of C/EBPalpha function may be causatively related to the leukemogenic potential of RUNX1/EVI1.

Unbalanced translocation der(1;7)(q10;p10) defines a unique clinicopathological subgroup of myeloid neoplasms

The unbalanced translocation, der(1;7)(q10;p10), is one of the characteristic cytogenetic abnormalities found in myelodysplastic syndromes (MDS) and other myeloid neoplasms. Although described frequently with very poor clinical outcome and possible relationship with monosomy 7 or 7q- (-7/7q-), this recurrent cytogenetic abnormality has not been explored fully. Here we analyzed retrospectively 77 cases with der(1;7)(q10;p10) in terms of their clinical and cytogenetic features, comparing with other 46 adult -7/7q- cases without der(1;7)(q10;p10). In contrast with other -7/7q- cases, where the abnormality tends to be found in one or more partial karyotypes, der(1;7)(q10;p10) represents the abnormality common to all the abnormal clones and usually appears as a sole chromosomal abnormality during the entire clinical courses, or if not, is accompanied only by a limited number and variety of additional abnormalities, mostly trisomy 8 and/or loss of 20q. der(1;7)(q10;p10)-positive MDS cases showed lower blast counts (P<0.0001) and higher hemoglobin concentrations (P<0.0075) at diagnosis and slower progression to acute myeloid leukemia (P=0.0043) than other -7/7q- cases. der(1;7)(q10;p10) cases showed significantly better clinical outcome than other -7/7q cases (P<0.0001). In conclusion, der(1;7)(q10;p10) defines a discrete entity among myeloid neoplasms, showing unique clinical and cytogenetic characteristics.

Analysis of abietic acid and dehydroabietic acid in food samples by in-tube solid-phase microextraction coupled with liquid chromatography-mass spectrometry

A simple and sensitive method for the determination of abietic acid and dehydroabietic acid in food samples was developed using a fully automated method consisting of in-tube solid-phase microextraction (SPME) coupled with liquid chromatography-mass spectrometry (LC/MS). These compounds were separated within 5min by HPLC using an ODS-3 column and 5mM ammonium formate/acetonitrile (10/90, v/v). Electrospray ionization conditions in the negative ion mode were optimized for MS detection of abietic acid and dehydroabietic acid. The optimum in-tube SPME conditions were 20draw/eject cycles of 40microL of sample using a Supel Q PLOT capillary column as an extraction device. The extracted compounds were easily desorbed from the capillary by passage of the mobile phase, and no carryover was observed. Using the in-tube SPME LC/MS method, good linearity of the calibration curve (r>0.9998) was obtained in the concentration range from 0 to 50ng/mL, and the detection limits (S/N=3) of abietic acid and dehydroabietic acid were 2.9 and 2.1pg/mL, respectively. The in-tube SPME method showed above 75-fold greater sensitivity than the direct injection method (5microL injection). This method was applied successfully to analysis of food samples without interference peaks. The recoveries of abietic acid and dehydroabietic acid spiked into liquid samples were above 79%, and the relative standard deviations were below 6.6%. These compounds were detected at ng/mL or ng/g levels in various liquid or solid food samples contacted with paper.

[Asian variant of intravascular large B-cell lymphoma diagnosed by bone marrow biopsy]

A 63-year-old male presented with fever and general malaise in June 2004. On admission hepatosplenomegaly was apparent, but without lymphadenopathy. The laboratory examination revealed pancytopenia and increased levels of lactate dehydrogenase, direct bilirubin and soluble interleukin-2 receptor. Histological analysis of the bone marrow biopsy specimen demonstrated proliferation of atypical lymphoid cells positive for CD20 in the small capillaries, leading to the diagnosis of the Asian variant of intravascular large B-cell lymphoma (AIVL). The presence of rearrangement of the immunoglobulin gene confirmed the diagnosis. The patient responded well to CHOP therapy followed by seven courses of rituximab-combined CHOP therapy and has remained in complete remission up to the present. This case implies that bone marrow biopsy could be a useful examination for diagnosing AIVL and that rituximab-combinedchemotherapy could improve survival in patients with the disease.

Beneficial effect of interferon-β treatment in patients with multiple sclerosis is associated with transient increase in serum IL-6 level in response to interferon-β injection

In order to predict the clinical benefit of interferon-beta (IFN-beta) to patients with multiple sclerosis (MS), the following markers were investigated; (1) chronological change of cytokines (IFN-gamma, TNF-alpha, IL-6, IL-10, and TGF-beta) after administration of IFN-beta, (2) untoward effects of IFN-beta such as headache and arthralgia, (3) backgrounds of the patients such as age and relapse rate, (4) efficacy of IFN-beta therapy assessed by the change of relapse rate and progression of disability. Chronological blood sampling was performed 0, 10, and 24 h after injection of IFN-beta. The increase of serum IL-6 level in response to IFN-beta administration was associated with headache, arthralgia, relapse rate before treatment, and disability score at the initiation of the therapy. Significant association of change of serum TNF-alpha with age and headache was also observed. The important finding in this study was that patients with a transient increase in IL-6 in response to IFN-beta showed a slow disease progression. This result suggests that this transient increase in the serum IL-6 predicts favorable response to IFN-beta treatment.

TEL/ETV6 induces apoptosis in 32D cells through p53-dependent pathways

TEL is an ETS family transcription factor that is critical for maintaining hematopoietic stem cells in adult bone marrow. To investigate the roles of TEL in myeloid proliferation and differentiation, we introduced TEL cDNA into mouse myeloid 32Dcl3 cells. Overexpression of TEL repressed interleukin-3-dependent proliferation through blocking cell cycle progression. Also, the presence of TEL triggered apoptosis through the mitochondrial intrinsic pathway on exposure to granulocyte colony-stimulating factor. We found an increase in p53 protein and its DNA binding in the TEL-overexpressing cells. Forced expression of TEL stimulated transcription via the p53-responsive element and increased the expression of cellular target genes for p53 such as cell cycle regulator p21 and apoptosis inducer Puma. Consistently, induction of apoptosis was delayed by pifithrin-alpha treatment and completely blocked by increased expression of Bcl-2 in the TEL-overexpressing cells. These data collectively suggest that TEL exerts a tumor suppressive function through augmenting the p53 pathway and facilitates normal development of myelopoiesis.

Gene Expression Profiles of CD133-positive Fractions Predict the Survival of Individuals with Acute Myeloid Leukemia

BACKGROUND

The current classification of acute myeloid leukemia (AML) is based predominantly on the cytogenetic abnormalities and morphology of the malignant blasts and is not always helpful for optimization of the treatment strategy. Gene expression profiles of AML blasts were obtained and a gene expression-based means of predicting the outcome of AML patients was developed.

MATERIALS AND METHODS

CD133-positive hematopoietic stem cell-like fractions were purified from the bone marrow of 99 individuals with AML-related disorders and the expression profiles of ~33,000 human transcripts in these cells were characterized with the use of DNA microarray analysis.

RESULTS

The comparison of the expression data between individuals with short- or long-term survival by application of Cox's proportional hazard model led to the identification of four genes, whose expression patterns discriminated between the two groups. The gene expression-based stratification (GES) system, based on a combination of the karyotype approach and the risk index calculated from the expression levels of the four outcome predictor genes, was developed to separate the patients into subgroups with distinct prognoses.

CONCLUSION

DNA microarray analysis of purified fractions provides novel stratification schemes for AML based on the expression profiles of a handful of genes.

A Randomized Controlled Trial to Compare Once- versus Twice-Daily Filgrastim for Mobilization of Peripheral Blood Stem Cells from Healthy Donors

Although the mobilization of peripheral blood stem cells from normal donors using granulocyte colony-stimulating factor is widely used, the ideal method for the administration of filgrastim has not been determined. Therefore, we compared the efficacy of peripheral blood stem cell mobilization on day 4 of filgrastim between once-daily (group O) and twice-daily (group T) administration of filgrastim at 400 microg/m(2)/d. In all, 38 and 34 donors were randomly assigned to groups O and T, respectively. The number of CD34(+) cells collected on day 4 was not significantly different (1.74 x 10(6) cells/kg in group O and 2.08 x 10(6) cells/kg in group T, P = .37). The incidence and severity of adverse events were similar in the two groups. The baseline white blood cell count was the strongest predictor of poor mobilization. Donor age, sex, and serum concentrations of several cytokines did not significantly affect the CD34(+) cell yield. In conclusion, once-daily administration of filgrastim at 400 microg/m(2)/d appeared to be appropriate for the mobilization of CD34(+) cells in normal donors when apheresis is planned on day 4 of filgrastim. Selection of a donor with a steady-state white blood cell count of 5.0 x 10(9)/L or more may lead to a lower incidence of poor mobilization.

[Disappearance of a Philadelphia chromosome-positive clone and appearance of a -negative clone following treatment with imatinib mesylate in acute myelomonocytic leukemia]

A 63-year-old female was diagnosed as having Philadelphia chromosome-positive acute myelomonocytic leukemia in June 2002. The patient received monotherapy with imatinib mesylate or combination therapy with DCM and idarubicin/cytarabine, both of which failed in attaining disease remission. However, the second imatinib administration plus CAG therapy resulted in disappearance of the Philadelphia chromosome-positive clone and increase of Philadelphia chromosome-negative cells. During a therapy-withholding period due to fungal infection, the Philadelphia chromosome-positive clone expanded and the patient died of cerebral hemorrhage in February 2003. The transient suppression of the Philadelphia chromosome-positive clone may have brought about amplification of the Philadelphia chromosome-negative cells after the secondary imatinib treatment.

A randomized, postremission comparison of four courses of standard-dose consolidation therapy without maintenance therapy versus three courses of standard-dose consolidation with maintenance therapy in adults with acute myeloid leukemia: the Japan Adult Leukemia Study Group AML 97 Study

BACKGROUND

A major concern in the treatment of patients with acute myeloid leukemia (AML) is how to prevent disease recurrences. Although intensive consolidation therapy has proven useful, the effectiveness of maintenance therapy remains controversial.

METHODS

Seven hundred eighty-nine patients ages 15-64 (median: 45 yrs) with de novo AML received induction therapy, which consisted of cytosine arabinoside (at a dose of 100 mg/m(2) on Days 1-7) and idarubicin (at a dose of 12 mg/m(2) on Days 1-3). The patients who achieved complete remission (CR) were then randomized into groups that received either four courses of standard-dose consolidation therapy without maintenance (Arm A) or three courses of standard-dose consolidation and six courses of maintenance therapy (Arm B).

RESULTS

In total, 78.7% of patients achieved CR. The 5-year overall survival (OS) rate for the 789 eligible patients was 46.9%, and the disease-free survival (DFS) rate for the 621 patients who achieved CR was 32.9%. The 5-year OS rate for Arm A was 52.4%, and 58.4% for Arm B (P = 0.599). The 5-year DFS rate for the patients who achieved CR was 35.8% in Arm A and 30.4% in Arm B (P = 0.543). In analyzing the data according to the risk groups, no statistical difference was observed either in the 5-year OS rate or in the 5-year DFS rate between the 2 arms.

CONCLUSIONS

In the current study, the Japan Adult Leukemia Study Group's conventional postremission therapy (three courses of standard-dose consolidation and six courses of maintenance therapy) was replaced successfully by a shorter duration of four courses of standard-dose consolidation therapy without the need for additional maintenance therapy.

Runx1/AML1 in normal and abnormal hematopoiesis

Runx1/AML1 (also known as CBFA2 and PEBP23B) is a Runt family transcription factor critical for normal hematopoiesis. Runx1 forms a heterodimer with CBF3 and binds to the consensus PEBP2 sequence through the Runt domain. Runx1 enhances gene transcription by interacting with transcriptional coactivators such as p300 and CREB-binding protein. However, Runx1 can also suppress gene transcription by interacting with transcriptional corepressors, including mSin3A, TLE (mammalian homolog of Groucho), and histone deacetylases. Runx1 not only is critical for definitive hematopoiesis in the fetus but also is required for normal megakaryocytic maturation and T-lymphocyte and B-lymphocyte development in adult mice. Runx1 has been identified in leukemia-associated chromosomal translocations, including t(8;21) (Runx1-ETO/MTG8), t(16;21) (Runx1-MTG16), t(3;21) (Runx1-Evi1), t(12;21) (TEL-Runx1), and t(X;21) (Runx1-Fog2). The molecular mechanism of leukemogenesis by these fusion proteins is discussed. Various mutant mice expressing these fusion proteins have been created. However, expression of the fusion protein is not sufficient by itself to cause leukemia and likely requires additional events for leukemogenesis. Point mutations in a Runx1 allele cause haploinsufficiency and a biallelic null for Runx1, which are associated with familial platelet disorder with a propensity for acute myeloid leukemia (FPD/AML) and AML-M0, respectively. Thus, the correct protein structure and the precise dosage of Runx1 are essential for the maintenance of normal hematopoiesis.

[Clinical course of the disease and the level of WT1 mRNA in 191 patients with acute myeloid leukemia (AML): joint research by 23 institutions in Japan]

We evaluated the clinical course of acute myeloid leukemia (AML) and the levels of WT1 mRNA in 191 AML patients. Of 114 previously untreated patients with AML, 107 cases were positive for WT1 mRNA (93.9% : 107/114). WT1 mRNA expression-levels declined to below 50 copies/microg RNA ("negative") after remission was achieved in all 66 patients who achieved remission and 84.8% (47/54) cases were "negative" at the end of the follow-up periods. On the other hand, WT1 mRNA was expressed in 87.0% of non-remission cases (47/54), maintaining 50 copies/microg of RNA or higher ("positive"). In all 29 cases who relapsed during the follow-up observation period after achieving remission, WT1 mRNA levels declined transiently approximately around the time of achieving remission and then rose again when the disease relapsed. Moreover, we determined the time of elevation of WT1 mRNA in 29 relapsed cases. In 79.3% of relapsed cases (23/29), WT1 mRNA levels rose above 200 copies/microg RNA, 43 days (median) before the diagnosis of "relapse". Given the percent of the correct diagnosis, WT1 mRNA at 200 copies/microg RNA appeared to be a reasonable cut-off level for early detection of AML-relapse. The WT1 mRNA level reflected the clinical condition. Taken together, these findings indicate that WT1 mRNA levels allow us to detect the presence of so-called "minimal residual disease" (leukemic cells) that cannot be detected by morphological examination. Besides these promising data, this kit is suitable for routine monitoring of AML because this kit utilizes peripheral blood as a test specimen, reducing the patient's burden at the time of collection of clinical samples as compared with bone marrow aspirate.

Comparison between reduced intensity and conventional myeloablative allogeneic stem-cell transplantation in patients with hematologic malignancies aged between 50 and 59 years

To evaluate the efficacy of reduced-intensity stem-cell transplantation (RIST), we retrospectively compared outcomes of 207 consecutive Japanese patients aged between 50 and 59 years with hematologic malignancies who received RIST (n=70) and conventional stem-cell transplantation (CST) (n=137). CST recipients received total body irradiation (TBI)-based or busulfan/cyclophosphamide-based regimens. RIST regimens were purine analog-based (n=67), 2 Gy TBI-based (n=2), and others (n=1). Most CST recipients (129/137) received calcineurin inhibitors and methotrexate as graft-versus-host (GVHD) prophylaxis, while 32 RIST recipients received cyclosporin. In all, 23 CST and five RIST recipients died without disease progression within 100 days of transplant. Grade II to IV acute GVHD occurred in 56 CST and 38 RIST recipients. There was no significant difference in overall survival (OS) and progression-free survival between CST and RIST. On multivariate analysis on OS, five variables were significant: preparative regimens (CST vs RIST) (hazard ratio=1.92, 95% confidence interval, 1.25-2.97; P=0.003), performance status (2-4 vs 0-1) (2.50, 1.51-4.16; P<0.001), risk of underlying diseases (1.85, 1.21-2.83; P=0.004), acute GVHD (2.57, 1.72-3.84; P<0.001), and CML (0.38, 0.21-0.69; P=0.002). We should be careful in interpreting results of this small-sized retrospective study; however, reduced regimen-related toxicity might contribute to better survival in RIST. The low relapse rates following RIST suggest a strong antitumor activity through allogeneic immunity.

Assessment of the international prognostic scoring system for determining chemotherapeutic indications in myelodysplastic syndrome: Japanese retrospective multicenter study

To standardize a rational therapeutic strategy of chemotherapy using the International Prognostic Scoring System (IPSS), we retrospectively analyzed 292 high-risk myelodysplastic syndrome (MDS) patients in 20 hospitals in Japan. Results of multivariate analysis of the data on patients who received all types of chemotherapy indicated that poor cytogenetics as shown by the IPSS was the only significant risk factor (P = .047). We then focused on the IPSS composition of each patient. The intermediate 2 (Int-2) category consisted of a heterogeneous group. We attempted to subdivide the category into Int-2A and Int-2B. Patients with good or intermediate cytogenetics had > or = 5% bone marrow (BM) blasts (Int-2A), and most of the other patients had poor cytogenetics and < or = 10% BM blasts (Int-2B). In the Int-2B category, overall survival for patients who received chemotherapy was significantly worse than for those who did not receive chemotherapy (P = .005). Most patients in the High category who had the diagnosis of MDS according to the World Health Organization classification had poor overall survival with or without chemotherapy. We propose the Int-2B and High categories may be considered possible high risk, whereas all patients in the Int-2A category and patients with more than 5% BM blasts in the Int-1 category may be categorized as being at possible intermediate risk. Our proposition may be useful for developing a chemotherapeutic strategy for patients with MDS in Japan.