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We analyzed 447 patients with de novo AML using alpha-satellite probes for the chromosomes 7, 8, X, and Y and RT-PCR for t(8;21), t(15;17) and inv(16). In 130/447 patients (29%) chromosomal aberrations were found. Thirty-three patients (7%) had a t(8;21); 11 of these had the additional loss of a sex chromosome (p<0.001) and two a trisomy 8. Twenty-nine patients (6%) had a t(15;17); four of these had a trisomy 8. Sixteen patients (4%) displayed an inv(16); four of these had a trisomy 8. Twenty-two patients (5%) had a sole trisomy 8 and one patient the combination of trisomy 8 and trisomy X. Five patients (1%) displayed the loss of a Y-chromosome as the sole abnormality and two patients had a sole trisomy X. In 22 patients (5%) a monosomy 7 was found, and in none of these patients were additional chromosomal aberrations detected by RT-PCR (p < 0.05). In conclusion, trisomy 8 and the loss of a gonosome are frequently associated with structural chromosomal aberrations with a significant association of -X/Y and t(8;21). The absence of these genomic lesions in AMLs with monosomy 7 suggests that the monosomy 7 has a specific role in the development of these leukemias and their clinical course. [ABSTRACT FROM AUTHOR]

Monosomal karyotype (MK) is associated with an adverse prognosis in patients in acute myeloid leukemia (AML). This study analyzes the prognostic impact of MK in a cohort of primary, untreated patients with myelodysplastic syndromes (MDS). A total of 431 patients were extracted from an international database. To analyze whether MK is an independent prognostic marker in MDS, cytogenetic and clinical data were explored in uni- and multivariate models regarding overall survival (OS) as well as AML-free survival. In all, 204/431 (47.3%) patients with MK were identified. Regarding OS, MK was prognostically significant in patients with 4 abnormalities only. In highly complex karyotypes (5 abnormalities), MK did not separate prognostic subgroups (median OS 4.9 months in MK+ vs 5.6 months in patients without MK, P=0.832). Based on the number of abnormalities, MK-positive karyotypes (MK+) split into different prognostic subgroups (MK+ and 2 abnormalities: OS 13.4 months, MK+ and 3 abnormalities: 8.0 months, MK+ and 4 abnormalities: 7.9 months and MK+ and 5 abnormalities: 4.9 months; P<0.01). In multivariate analyses, MK was not an independent prognostic factor. Our data support the hypothesis that a high number of complex abnormalities, associated with an instable clone, define the subgroup with the worst prognosis in MDS, independent of MK. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article on the recurrent acute myeloid leukemia 1-ETO (AML1-ETO) fusion in chronic myeloid leukemia (CML).

The majority of patients with myelodysplastic syndrome (MDS) present with anemia and will become dependent on regular transfusions of packed red blood cells (PRBC) with the risk of iron overload (IOL). Liver iron content best reflects the total body iron content, and measurement of liver iron concentration (LIC) by MRI is a validated tool for detection, but data in MDS is rather limited. Here we present the results of a multi-center trial evaluating the efficacy and safety of deferasirox (DFX) in low and intermediate-1 risk MDS patients with transfusion-dependent IOL. Three patients with transfusion frequency of > 4 units PRBC per month were initially treated with 30 mg/kg/day while in 46 patients with a lower transfusion burden deferasirox was initiated at 20 mg/kg/day, due to patient related reasons one patient received DFX in a dose of 6 mg/kg/day only. LIC was measured by MRI at baseline and end of study using the method by St. Pierre et al. The intention to treat population consisted of 50 MDS patients (28 male; 22 female) with a median age of 69 years who were treated with DFX for a median duration of 354 days. Mean daily dose of DFX was 19 mg/kg/day. Median serum ferritin level (SF) at baseline was 2,447 ng/mL and decreased to 1,685 ng/mL (reduction by 31 %) at end of study ( p = 0.01). In 7 (13 %) patients the initially chosen dose had to be increased due to unsatisfactory efficacy of chelation therapy. For 21 patients, LIC measurement by liver MRI was performed at baseline and for 19 of these patients at the end of study: mean LIC decreased significantly from 16,8 mg/g dry tissue weight (± 8.3 mg/g dry tissue weight) at study entry to 10,8 mg/g dry tissue weight (± 10.4 mg/g dry tissue weight) at end of study ( p = 0.01). Of all patients exposed to the study drug ( n = 54), 28 (52 %) did not complete the 12 month study period most commonly due to AEs in 28 % ( n = 15) and abnormal laboratory values in 7 % ( n = 4), respectively. The most common adverse events (≥ 10 % of all patients) with suspected drug relationship were diarrhea ( n = 25, 46 %), nausea ( n = 13, 24 %), upper abdominal pain ( n = 8, 15 %), serum creatinine increase ( n = 16, 30 %) and rash ( n = 5, 9 %). Adverse events making dose adjustments or interruption of study drug necessary occurred in 33 patients (61 %). Hematologic improvement according to IWG criteria (2006) was observed in 6 patients (11 %). Initiation of treatment of IOL with DFX depending on the transfusion burden yields sufficient reduction of excess iron indicated by serum ferritin levels and most importantly by liver MRI. The safety profile of DFX was comparable to previous observations. [ABSTRACT FROM AUTHOR]

Myelodysplastic syndromes (MDS) with del(5q) are considered to have a benign course of the disease. In order to address the issue of the propensity of those patients to progress to acute myeloid leukemia (AML), data on 381 untreated patients with MDS and del(5q) characterized by low or intermediate I International Prognostic Scoring System (IPSS) risk score were collected from nine centers and registries. Median survival of the entire group was 74 months. Transfusion-dependent patients had a median survival of 44 months vs 97 months for transfusion-independent patients (P<0.0001). Transfusion need at diagnosis was the most important patient characteristic for survival. Of the 381 patients, 48 (12.6%) progressed to AML. The cumulative progression rate calculated using the Kaplan-Meier method was 4.9% at 2 years and 17.6% at 5 years. Factors associated with the risk of AML transformation were high-risk World Health Organization adapted Prognostic Scoring System (WPSS) score, marrow blast count >5% and red-cell transfusion dependency at diagnosis. In conclusion, patients with MDS and del(5q) are facing a considerable risk of AML transformation. More detailed cytogenetic and molecular studies may help to identify the patients at risk of progression. [ABSTRACT FROM AUTHOR]

The chromosomal translocation (8;21) fuses the hematopoietic transcription factor AML1 (RUNX1) with ETO (RUNX1T1, MTG8), resulting in the leukemia-specific chimeric protein AML1/ETO. This fusion protein has been implicated in epigenetic silencing, recruiting histone deacetylases (HDACs) and DNA methyltransferases to target promoters. Previously, we have identified a novel in vivo AML1/ETO target gene, LAT2 (NTAL/LAB/WBSCR5), which is involved in FcɛR I, c-Kit, B-cell and T-cell receptor signalling. We have now addressed the molecular mechanisms of AML1/ETO-mediated LAT2 repression. In Kasumi-1 cells, where AML1/ETO bound to the LAT2 gene, small interfering RNA (siRNA)-mediated AML1/ETO depletion caused upregulation of LAT2, suggesting a possible direct mechanism of repression. Expression of AML1/ETO was associated with a decrease in acetylation of histones H3, H3K9 and H4, and an increase in H3K9 and H3K27 trimethylation. The class I-specific HDAC inhibitors entinostat (MS-275) and mocetinostat (MGCD0103) induced LAT2 expression specifically in AML1/ETO-expressing cells, resulting in induction of several activating histone marks on the LAT2 gene, including trimethylation of histone H3K4. The combination of entinostat and decitabine increased acetylation of histones H3 and H4, as well as LAT2 mRNA expression, in an at least additive fashion. In conclusion, several repressive histone modifications mark the LAT2 gene in the presence of AML1/ETO, and LAT2 gene derepression is achieved by pharmacological inhibition of HDACs. [ABSTRACT FROM AUTHOR]

We have piloted a low-dose schedule of 5-azacytidine followed by donor lymphocyte infusions (DLIs) in patients with relapse of AML or chronic myelomonocytic leukemia (CMMoL) after allografting. Of the 26 patients (median age 62 years, range 28–75) with relapsed AML (n=24) or CMMoL (n=2), 11 (42%) had poor-risk cytogenetics. Twenty-three patients had received fludarabine-based reduced-toxicity conditioning regimens, and three had received conventional myeloablative conditioning. Patients received 5-azacytidine s.c., at a total daily dose of 100 mg, on days 1–3, to be followed by DLI on day 10, with the next course of treatment to be started on day 22. A total of 60 courses of 5-azacytidine were administered, with a median of 2 courses (range: 1–10). In 44 courses, 5-azacytidine was followed by DLI, and thus 19/26 (73%) patients received at least one course of this combined treatment. Clinically relevant neutropenic infections not associated with progressive disease developed in four patients, one of them succumbing to sepsis. Only two patients developed de novo acute GvHD after the combination of 5-azacytidine and DLI. Overall, 66% of the patients benefited from this treatment, with continued CRs achieved in 4 (16%) patients, lasting a median of 525 days (range: 450+ to 820+), and a 50% rate of temporary disease control with stable mixed chimerism (median duration 72 days). The median survival from the start of 5-azacytidine treatment was 136 days (range: 23 to 873+), with an estimated 2-year survival probability of 16%. In conclusion, this non-intensive outpatient regimen of 5-azacytidine followed by DLI is feasible, with a very low aGVHD rate. Objective responses, including continuous complete donor chimerism, occurred also in patients with poor-risk cytogenetics. [ABSTRACT FROM AUTHOR]

Novel, non-intensive treatment options in older MDS/AML patients planned for allografting, with the goal of down-staging the underlying disease and bridging time to transplantation, are presently being developed. 5-azacytidine and decitabine (DAC) are of particular interest, as they can be given repetitively, with very limited non-hematologic toxicity and result in responses both in MDS and AML even at low doses. We describe 15 consecutive patients (median age 69 years, range 60–75 years) with MDS (n=10) or AML (n=5) who all received first-line treatment with DAC and subsequent allografting (from sibling donor in four patients, unrelated donor in 11) after reduced-intensity conditioning with the FBM regimen. Successful engraftment was attained in 14/15 patients, all of whom achieved a CR, with a median duration of 5 months (range 1+ to 51+). Six of these 14 patients are alive (4 with complete donor chimerism), 8 have died either from relapse (n=4) or treatment-related complications while in CR (n=4). We conclude that allografting after low-dose DAC and subsequent conditioning with FBM is feasible, with no unexpected toxicities and appears as a valid alternative to standard chemotherapy (‘InDACtion instead of induction’) in elderly patients with MDS/AML. [ABSTRACT FROM AUTHOR]

A great proportion of acute myeloid leukemias (AMLs) display cytogenetic abnormalities including chromosomal aberrations and/or submicroscopic mutations. These abnormalities significantly influence the prognosis of the disease. Hence, a thorough genetic work-up is an essential constituent of standard diagnostic procedures. Core binding factor (CBF) leukemias denote AMLs with chromosomal aberrations disrupting one of the CBF transcription factor genes; the most common examples are translocation t(8;21) and inversion inv(16), which result in the generation of the AML1-ETO and CBFβ-MYH11 fusion proteins, respectively. However, in murine models, these alterations alone do not suffice to generate full-blown leukemia, but rather, complementary events are required. In fact, a substantial proportion of primary CBF leukemias display additional activating mutations, mostly of the receptor tyrosine kinase (RTK) c-KIT. The awareness of the impact and prognostic relevance of these ‘second hits’ is increasing with a wider range of mutations tested in clinical trials. Furthermore, novel agents targeting RTKs are emanating rapidly and entering therapeutic regimens. Here, we present a concise review on complementing mutations in CBF leukemias including pathophysiology, mouse models, and clinical implications.Oncogene (2008) 27, 5759–5773; doi:10.1038/onc.2008.196; published online 7 July 2008 [ABSTRACT FROM AUTHOR]