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We describe genetic and clinical characteristics of acute myeloid leukemia (AML) patients according to age from an academic population-based registry. Adult patients with newly diagnosed AML at 63 centers in Germany and Austria were followed within the AMLSG BiO registry (NCT01252485). Between January 1, 2012, and December 31, 2014, data of 3525 patients with AML (45% women) were collected. The median age was 65 years (range 18–94). The comparison of age-specific AML incidence rates with epidemiological cancer registries revealed excellent coverage in patients 0 were associated with non-intensive treatment or best supportive care. The AMLSG BiO registry provides reliable population-based distributions of genetic, clinical, and treatment characteristics according to age. Electronic supplementary material The online version of this article (10.1007/s00277-017-3150-3) contains supplementary material, which is available to authorized users.

Although the transforming potential of Hox genes is known for a long time, it is not precisely understood to which extent splicing is important for the leukemogenicity of this gene family. To test this for Hoxa9, we compared the leukemogenic potential of the wild-type Hoxa9, which undergoes natural splicing, with a full-length Hoxa9 construct, which was engineered to prevent natural splicing (Hoxa9FLim). Inability to undergo splicing significantly reduced in vivo leukemogenicity compared to Hoxa9-wild-typed. Importantly, Hoxa9FLim could compensate for the reduced oncogenicity by collaborating with the natural splice variant Hoxa9T, as co-expression of Hoxa9T and Hoxa9FLim induced acute myeloid leukemia (AML) after a comparable latency time as wild-type Hoxa9. Hoxa9T on its own induced AML after a similar latency as Hoxa9FLim, despite its inability to bind DNA. These data assign splicing a central task in Hox gene mediated leukemogenesis and suggest an important role of homeodomain-less splice variants in hematological neoplasms.

We evaluated the frequency, genetic architecture, clinico-pathologic features and prognostic impact of RUNX1 mutations in 2439 adult patients with newly-diagnosed acute myeloid leukemia (AML). RUNX1 mutations were found in 245 of 2439 (10%) patients; were almost mutually exclusive of AML with recurrent genetic abnormalities; and they co-occurred with a complex pattern of gene mutations, frequently involving mutations in epigenetic modifiers (ASXL1, IDH2, KMT2A, EZH2), components of the spliceosome complex (SRSF2, SF3B1) and STAG2, PHF6, BCOR. RUNX1 mutations were associated with older age (16-59 years: 8.5%; ⩾60 years: 15.1%), male gender, more immature morphology and secondary AML evolving from myelodysplastic syndrome. In univariable analyses, RUNX1 mutations were associated with inferior event-free (EFS, P

Clinical impact of GATA2 mutations in acute myeloid leukemia patients harboring CEBPA mutations: a study of the AML study group

Mit der Identifizierung der JAK2 V617F-Mutation bei der essentiellen Thrombozythamie (ET), der Polyzythamia vera (PV) und der Myelofibrose (MF) im Jahr 2005, wurden erstmals neue und wichtige Einblicke in die Pathogenese myeloproliferativer Neoplasien (MPN) gewonnen werden. Basierend auf diesen Erkenntnissen wurden eine Reihe neuer Substanzen entwickelt oder bereits etablierte Substanzen weiter modifiziert, die derzeit in klinischen Studien bei Patienten mit MPN evaluiert werden. Die meisten Daten liegen derzeit zu den JAK-Inhibitoren, sog. „ATP mimetics” zur Therapie der MF vor. Hier wurden aktuell erste, sehr viel versprechende Ergebnisse aus zwei Phase-III-Studien publiziert, die zeigen konnten, dass die Therapie mit dem JAK1 /2-Inhibitor Ruxolitinib zu einer signifikanten Milzgrosenreduktion und einer deutlichen Verbesserung der Lebensqualitat von MF-Patienten fuhrt. Neben den JAK-Inhibitoren werden derzeit auch immunmodulatorische Substanzen, die IMiDs, zur Therapie der MPN eingesetzt. Hier hat sich Pomalidomid als sehr aktive Substanz in Phase-II-Studien erwiesen. Daruber hinaus kommen weitere Kinase-Inhibitoren sowie Histon-Deacetylase-(HDAC-) Inhibitoren und Inhibitoren des mTOR-Signalweges im Rahmen klinischer Studien zum Einsatz. Aufgrund ihrer unterschiedlichen, teils synergistischen Wirkmechanismen sind auch erste Kombinationstherapien in Planung, durch die man sich eine weitere Verbesserung des Ansprechens erhofft. In der Ubersichtsarbeit sollen die aktuellen Ergebnisse zum Einsatz dieser Substanzen vorgestellt und diskutiert sowie weitere neue Therapieansatze vorgestellt werden.

The G protein-coupled receptor 56 (GPR56) was identified as part of the molecular signature of functionally validated leukemic stem cells isolated from patients with acute myeloid leukemia (AML). This report now demonstrates particularly high expression of GPR56 in patients with mutant NPM1 and FLT3-length mutation and association of high GPR56 expression with inferior prognosis in a large patient cohort treated in two independent multicenter phase III trials. Functional relevance of GPR56 expression was validated in mice, in which co-expression of Gpr56 significantly accelerated HOXA9-induced leukemogenesis and vice versa knockdown of Gpr56 delayed onset of HOXA9/MEIS1-induced AML. Overexpression of Gpr56 grossly changed the molecular phenotype of Hoxa9-transduced cells affecting pathways involved in G protein-coupled receptors (GPRCs) and associated intracellular signaling. Blockage of surface GPR56 by an anti-GPR56 antibody successfully impaired engraftment of primary human AML cells. In summary, these data demonstrate that high expression of GPR56 is able to contribute to AML development and characterize the GPR56 as a potential novel target for antibody-mediated antileukemic strategies.

The expression of tumor-associated antigens (TAAs) might play a critical role in the control of minimal residual disease (MRD) in acute myeloid leukemia (AML), and therefore might be associated with clinical outcome in AML. In a DNA microarray analysis of 116 AML samples, we found a significant correlation between high mRNA levels of G250/CA9 and longer overall survival (P = .022), a similar trend with high mRNA levels of PRAME (P = .103), and a hint for RHAMM/HMMR. In contrast, for other TAAs like WT1, TERT, PRTN3, BCL2, and LAMR1, we found no correlation with clinical outcome. High expression of at least 1 of the 3 TAAs, RHAMM/HMMR, PRAME, or G250/CA9, provided the strongest favorable prognostic effect (P = .005). Specific T-cell responses were detected in 8 (47%) of 17 patients with AML in complete remission for RHAMM/HMMR-R3 peptide, in 7 (70%) of 10 for PRAME-P3 peptide, and in 6 (60%) of 10 for newly characterized G250/CA9-G2 peptide, a significant increased immune response compared with patients with AML patients who had refractory disease (P < .001). Furthermore, we could demonstrate specific lysis of T2 cells presenting these epitope peptides. In conclusion, expression of the TAAs RHAMM/HMMR, PRAME, and G250/CA9 can induce strong antileukemic immune responses, possibly enabling MRD control. Thus, these TAAs represent interesting targets for polyvalent immunotherapeutic approaches in AML.

Purpose To evaluate prognostic factors for relapse-free survival (RFS) and overall survival (OS) and to assess the impact of different postremission therapies in adult patients with core binding factor (CBF) acute myeloid leukemias (AML). Patients and Methods Individual patient data–based meta-analysis was performed on 392 adults (median age, 42 years; range, 16 to 60 years) with CBF AML (t(8;21), n = 191; inv(16), n = 201) treated between 1993 and 2002 in prospective German AML treatment trials. Results RFS was 60% and 58% and OS was 65% and 74% in the t(8;21) and inv(16) groups after 3 years, respectively. For postremission therapy, intention-to-treat analysis revealed no difference between intensive chemotherapy and autologous transplantation in the t(8;21) group and between chemotherapy, autologous, and allogeneic transplantation in the inv(16) group. In the t(8;21) group, significant prognostic variables for longer RFS and OS were lower WBC and higher platelet counts; loss of the Y chromosome in male patients was prognostic for shorter OS. In the inv(16) group, trisomy 22 was a significant prognostic variable for longer RFS. For patients who experienced relapse, second complete remission rate was significantly lower in patients with t(8;21), resulting in a significantly inferior survival duration after relapse compared with patients with inv(16). Conclusion We provide novel prognostic factors for CBF AML and show that patients with t(8;21) who experience relapse have an inferior survival duration.

In recent years, the development of novel molecular techniques has been instrumental in deciphering the genetic heterogeneity of acute myeloid leukemia (AML) as well as in gaining important insights into the pathomechanisms of AML. Genetic diagnostics has become an essential component in the initial work-up for disease classification, prognostication, and genotype-specific therapies. A major prerequisite for such individualized treatment strategies is a rapid pretherapeutic genetic analysis, which includes screening for the recurrent AML-associated gene fusions as well as mutations in the genes NPM1, FLT3, and CEBPA. Some of these molecular markers can be used for monitoring minimal residual disease and therefore provide clinically relevant information. There is an increasing number of promising molecularly targeted therapies in clinical development for distinct genetic AML subgroups. Solid data exist for the combination of all-trans retinoic acid and arsentrioxid in the treatment of acute promyelocytic leukemia; the addition of the immunoconjugate gemtuzumab ozogamicin (GO) to induction therapy has been shown to improve outcome in cytogenetic low- and intermediate-risk AML. Furthermore, there are encouraging data on the combination of intensive chemotherapy with tyrosine kinase inhibitors in patients with AML harboring FLT3 mutations or with core-binding factor AML. Other novel therapeutic approaches address mutations or alterations in epigenetic regulators, such as IDH or DOT1L inhibitors. The comprehensive characterization of the underlying genetic mechanisms is essential for the development of novel target-specific compounds with the aim of improving outcome in AML patients.

Since the discovery of the gain-of-function mutation JAK2 V617F in 2005, an increasing number of mutations have been described in myeloproliferative neoplasms (MPN) and related myeloid malignancies.1, 2, 3, 4 For instance, use of array-based techniques such as comparative genomic hybridization and single-nucleotide polymorphism (SNP) analysis led to the identification of genes involved in epigenetic regulation such as tet-oncogene family member 2 (TET2), additional sex combs like 1 (ASXL1) and enhancer of zeste 2 (EZH2).5, 6, 7 Inactivating mutations in TET2, ASXL1 and EZH2 are considered to promote myeloid tumorigenesis because of epigenetic modulation of target genes. More recently, a whole-genome sequencing study in acute myeloid leukemia (AML) uncovered recurrent mutations in 22% of AML patients in another epigenetic regulator, the DNA methyltransferase 3A gene DNMT3A.8 In this study, DNMT3A mutations were associated with poor outcome and, thus, are of clinical relevance. However, exact mechanisms of action of DNMT3A mutations are still unclear because global methylation patterns and 5-methylcytosine content in AML genomes were not significantly altered. Nevertheless, mutations of TET2, ASXL1, EZH2 and DNMT3A occur in a significant number of patients with myeloid malignancies underlining the pathogenic relevance of epigenetic changes.

A 51-year-old female patient in the first chronic phase of CML received an allogeneic PBSCT from a matched unrelated donor. The transplant was manipulated by CD34+ cell selection. On day +193 after transplantation the patient was readmitted to the hospital with recurrent fever of unknown origin and cough. Clinical, radiographic and sonographic evaluation revealed no characteristic findings besides a mild splenomegaly. Screening for EBV, CMV, RSV and HSV did not indicate an active infection. On day +203 the patient developed generalized seizures, respiratory failure and died within 24 h in multiorgan failure. The macroscopic postmortem was still not enlightening; the histological examination however, demonstrated diffuse organ infiltration by monoclonal lymphoblastoid cells due to EBV-LPD. Bone Marrow Transplantation (2001) 28, 615–618.

Background: The concept of intensive post-remission chemotherapy in acute myeloid leukemia (AML) is based on the observation that despite achievement of a first complete remission (CR) after intensive induction therapy virtually all patients relapse in the absence of further treatment. Moreover, randomized studies showed that intensive post-remission consolidation chemotherapy was superior to prolonged low-dose maintenance therapy in younger patients. With regard to consolidation therapy, the landmark study conducted by the Cancer and Leukemia Group B established the current standard for patients aged 60 years and younger with high-dose cytarabine (HDAC) 3g/m² bidaily on days days 1, 3, and 5. Aims: to compare a compressed schedule of high-dose cytarabine (HDAC) on days 1, 2, and 3 with the standard HDAC given on days 1, 3, and 5 as well as to evaluate the prophylactic use of pegfilgrastim after chemotherapy in patients in first CR receiving repetitive consolidation cycles for acute myeloid leukemia. Methods: Patients (18 to 60 years) were accrued between 2004 and 2009. They were randomized up-front 1:10 between the standard German intergroup-arm (Büchner et al. J Clin Oncol. 2012;30:3604-10) and the AMLSG 07-04 study (NCT00151242). Induction therapy in the AMLSG 07-04 study consisted of two cycles of idarubicin, cytarabine and etoposide +/- all-trans retionoic acid (ATRA) and +/- valproic acid (VPA) in a 2 by 2 factorial design. After recruitment of 392 patients the randomization for VPA was stopped due to toxicity. For consolidation therapy, patients with high-risk AML, defined either by high-risk cytogenetics or induction failure, were assigned to receive allogeneic hematopoietic cell transplantation from a matched related or unrelated donor. All other patients were assigned to 3 cycles of HDAC from 2004 to November 2006 with cytarabine 3g/m² bidaily, on days 1, 3, 5 and pegfilgrastim on day 10 (HDAC-135) and from December 2006 to 2009 patients were treated with a condensed schedule with cytarabine 3g/m², bidaily, on days 1,2,3 and pegfilgrastim on day 8 (HDAC-123). Patients randomized into the German AML intergroup arm were treated for consolidation therapy with cytarabine 3g/m² bid on days 1, 3, 5 (HDAC-135) without prophylactic growth-factor support. Results:Overall 568 patients receiving 1376 consolidation cycles were included into the study. According to up-front randomization 41 were treated with HDAC-135 without prophylactic growth factor support in the German AML Intergroup protocol, 135 with HDAC-135 and 392 with HDAC-123 with intended prophylactic pegfilgrastim at day 10 and 8, respectively, in the AMLSG 07-04 protocol. Time from start to chemotherapy until hematological recovery with leukocytes >1.0G/l and neutrophils >0.5G/l was significantly (p Conclusion: Data from our study suggest that consolidation therapy with a condensed schedule of HDAC-123 is superior to that of standard HDAC-135 in terms of faster hematological recovery, lower infection rate and fever days in hospital. In addition, the administration of one dose of pegfilgrastim after chemotherapy further shortened hematological recovery and reduced infection rate. Importantly, similar efficacy in terms of relapse-free and overall survival rates after HDAC-123 and HDAC-135 were observed. Disclosures Lübbert: Ratiopharm: Other: Study drug valproic acid; Janssen-Cilag: Other: Travel Funding, Research Funding; Celgene: Other: Travel Funding. Fiedler:GSO: Other: Travel; Pfizer: Research Funding; Teva: Other: Travel; Gilead: Other: Travel; Novartis: Consultancy; Ariad/Incyte: Consultancy; Kolltan: Research Funding; Amgen: Consultancy, Other: Travel, Patents & Royalties, Research Funding. Schlenk:Amgen: Research Funding; Pfizer: Honoraria, Research Funding.

Since the discovery of the JAK2V617F mutation in essential thrombocythemia (ET), polycythemia vera (PV) and myelofibrosis (MF) in 2005, the field of myeloproliferative neoplasms (MPN) experiences a significant gain of knowledge. Based on the novel insights in the molecular pathomechanisms of MPN many innovative drugs have been developed that are currently under investigation in clinical trials. Most data are available on the JAK inhibitors, the so called "ATP mimetics" for the treatment of MF. Recent data from two large phase-III studies showed that the JAK1 /2 inhibitor Ruxolitinib is very effective in the reduction of spleen size and the improvement of quality of life in MF patients. Beside JAK inhibitors, immunomodulatory drugs (IMiD) are currently under investigation. Here, pomalidomide showed significant activity in several phase-II studies in MF patients. In addition, other kinase inhibitors as well as histone deacetylase (HDAC) inhibitors and inhibitors of the mTOR signalling pathway are currently evaluated in clinical trials. Based on their potential synergistic action combination therapy of these substances represents another option for MPN therapy.In this review the most recently published studies using innovative treatment strategies in MPN patients are reported, and some future aspects for MPN treatment are adressed.

Recently, the p53-miR-34a network has been identified to have an important role in tumorigenesis. As in acute myeloid leukemia with complex karyotype (CK-AML) TP53 alterations are the most common known molecular lesion, we further analyzed the p53-miR-34a axis in a large cohort of CK-AML with known TP53 status (TP53(altered), n=57; TP53(unaltered), n=31; altered indicates loss and/or mutation of TP53). Profiling microRNA (miRNA) expression delineated TP53 alteration-associated miRNA profiles, and identified miR-34a and miR-100 as the most significantly down- and upregulated miRNA, respectively. Moreover, we found a distinct miR-34a expression-linked gene expression profile enriched for genes belonging to p53-associated pathways, and implicated in cell cycle progression or apoptosis. Clinically, low miR-34a expression and TP53 alterations predicted for chemotherapy resistance and inferior outcome. Notably, in TP53(unaltered) CK-AML, high miR-34a expression predicted for inferior overall survival (OS), whereas in TP53(biallelic altered) CK-AML, high miR-34a expression pointed to better OS. Thus, detailed molecular profiling links impaired p53 to decreased miR-34a expression, but also identifies p53-independent miR-34a induction mechanisms as shown in TP53(biallelic altered) cell lines treated with 15-deoxy-Δ(12,14)-prostaglandin. An improved understanding of this mechanism might provide novel therapeutic options to restore miR-34a function and thereby induce cell cycle arrest and apoptosis in TP53(altered) CK-AML.

To study the prevalence and prognostic importance of mutations in NADH dehydrogenase subunit 4 (ND4), a mitochondrial encoded transmembrane component of the electron transport chain respiratory Complex I, 452 AML patients were examined for ND4 mutations by direct sequencing. The prognostic impact of ND4 mutations was evaluated in the context of other clinical prognostic markers and genetic risk factors. In all, 29 of 452 patients (6.4%) had either somatic (n=12) or germline (n=17) ND4 mutations predicted to affect translation. Somatic mutations were more likely to be heteroplasmic (P

Core-binding factor (CBF) leukemias, characterized by translocations t(8;21) or inv(16)/t(16;16) targeting the CBF, constitute acute myeloid leukemia (AML) subgroups with favorable prognosis. However, about 40% of patients relapse and the current classification system does not fully reflect this clinical heterogeneity. Previously, gene expression profiling (GEP) revealed two distinct CBF leukemia subgroups displaying significant outcome differences and identified apoptotic signaling, MAPKinase signaling and chemotherapy-resistance mechanisms among the most significant differentially regulated pathways. We now tested different inhibitors of the respective pathways in a cell line model (six cell lines reflecting the CBF subgroup-specific gene expression alterations), and found apoptotic signaling to be differentiating between the CBF subgroup models. In accordance, primary samples from newly diagnosed CBF AML patients (n=23) also showed differential sensitivity to in vitro treatment with a Smac mimetic such as BV6, an antagonist of inhibitor of apoptosis (IAP) proteins, and ABT-737, a BCL2 inhibitor. Furthermore, GEP revealed the BV6-resistant cases to resemble the previously identified unfavorable CBF subgroup. Thus, our current findings show deregulated IAP expression and apoptotic signaling to differentiate clinically relevant CBF subgroups, which were independent of known molecular markers, thereby providing a starting point for novel therapeutic approaches.

The t(10;11)(p13-14;q14-21) translocation, giving rise to the CALM-AF10 fusion gene, is a recurrent chromosomal rearrangement observed in patients with poor prognosis acute myeloid leukemia (AML). Although splicing of the CALM-AF10 fusion transcripts has been described in AML patients, the contribution of different CALM and AF10 domains to in vivo leukemogenesis remains to be defined. We therefore performed detailed structure-function studies of the CALM-AF10 fusion protein. We demonstrate that fusion of the C-terminal 248 amino acids of CALM, which include the clathrin-binding domain, to the octapeptide motif-leucine-zipper (OM-LZ) domain of AF10 generated a fusion protein (termed CALM-AF10 minimal fusion (MF)), with strikingly enhanced transformation capabilities in colony assays, providing an efficient system for the expeditious assessment of CALM-AF10-mediated transformation. Leukemias induced by the CALM-AF10 (MF) mutant recapitulated multiple aspects of full-length CALM-AF10-induced leukemia, including aberrant Hoxa cluster upregulation, a characteristic molecular lesion of CALM-AF10 leukemias. In summary, this study indicates that collaboration of the clathrin-binding and the OM-LZ domains of CALM-AF10 is sufficient to induce AML. These findings further suggest that future approaches to antagonize CALM-AF10-induced transformation should incorporate strategies, which aim at blocking these key domains.Leukemia advance online publication, 17 June 2011; doi:10.1038/leu.2011.153.

Allogeneic stem cell transplant to eliminate germline mutations in the gene for CCAAT-enhancer-binding protein α from hematopoietic cells in a family with AML

Recent advances in genome-wide single-nucleotide polymorphism (SNP) analyses have revealed previously unrecognized microdeletions and uniparental disomy (UPD) in a broad spectrum of human cancers. As acute myeloid leukemia (AML) represents a genetically heterogeneous disease, this technology might prove helpful, especially for cytogenetically normal AML (CN-AML) cases. Thus, we performed high-resolution SNP analyses in 157 adult cases of CN-AML. Regions of acquired UPDs were identified in 12% of cases and in the most frequently affected chromosomes, 6p, 11p and 13q. Notably, acquired UPD was invariably associated with mutations in nucleophosmin 1 (NPM1) or CCAAT/enhancer binding protein-alpha (CEBPA) that impair hematopoietic differentiation (P=0.008), suggesting that UPDs may preferentially target genes that are essential for proliferation and survival of hematopoietic progenitors. Acquired copy number alterations (CNAs) were detected in 49% of cases with losses found in two or more cases affecting, for example, chromosome bands 3p13-p14.1 and 12p13. Furthermore, we identified two cases with a cryptic t(6;11) as well as several non-recurrent aberrations pointing to leukemia-relevant regions. With regard to clinical outcome, there seemed to be an association between UPD 11p and UPD 13q cases with overall survival. These data show the potential of high-resolution SNP analysis for identifying genomic regions of potential pathogenic and clinical relevance in AML.

To assess the prognostic impact of cytogenetics in elderly patients with acute myeloid leukemia (AML) receiving intensive induction and consolidation treatment according to a single protocol specifically designed for patients above age 60, pretreatment samples from 361 patients registered for the AML HD98-B trial of the German-Austrian AML Study Group were analyzed by chromosome banding and fluorescence in situ hybridization, and cytogenetic findings were correlated with outcome. Using a proportional hazards model with backward selection, 3 prognostic subgroups were identified based on the influence of cytogenetic abnormalities on overall survival (OS): low-risk, t(15;17), and inv(16) in 25 of 361 patients (7%); standard-risk, normal karyotype, t(8;21), t(11q23), +8 within a noncomplex karyotype, and +11 within a noncomplex karyotype in 208 of 361 patients (58%); high-risk, all other aberrations in 128 of 361 patients (35%). On multivariate analysis, high-risk cytogenetics (hazard ratio [HR], 2.24) and age above 70 years (HR, 2.34) were independent prognostic factors affecting OS, and stratification according to these parameters demonstrated that a large subgroup of patients (55%), characterized by age 70 or older or high-risk cytogenetics, or both, had very unfavorable treatment results despite intensive chemotherapy. Thus, karyotype and age are major determinants of outcome in elderly patients with AML.

The objective of our study was to evaluate high-dose cytarabine in consolidation therapy in patients with newly diagnosed acute promyelocytic leukemia (APL). Patients (age 16-60 years) received induction therapy according to the AIDA protocol (all-trans retinoic acid, idarubicin) followed by one cycle of ICE (idarubicin, cytarabine, etoposide) and two cycles of HAM (cytarabine 3 g/m(2) q12h, days 1-3; mitoxantrone 10 mg/m(2), days 2 and 3). From 1995 to 2003, 82 patients were enrolled. In total, 72 patients (88%) achieved a complete remission, and 10 patients (12%) died from early/hypoplastic death (ED/HD). A total of 71 patients received at least one cycle of HAM. Relapse-free survival (RFS) and overall survival (OS) after 46 months were 83 and 82%, respectively. White blood cell count above 10.0 x 10(9)/l at diagnosis and additional chromosomal aberrations were unfavorable prognostic markers for OS, whereas no prognostic markers for RFS were identified including FLT3 mutations. In conclusion, high-dose cytarabine in consolidation therapy for patients with newly diagnosed APL is an effective treatment approach.

Upon infection, virions or subviral nucleoprotein complexes are transported from the cell surface to the site of viral transcription and replication. During viral egress, particles containing viral proteins and nucleic acids again move from the site of their synthesis to that of virus assembly and further to the plasma membrane. Because free diffusion of molecules larger than 500 kDa is restricted in the cytoplasm, viruses as well as cellular organelles employ active, energy-consuming enzymes for directed transport. This is particularly evident in the case of neurotropic viruses that travel long distances in the axon during retrograde or anterograde transport. Viruses use two strategies for intracellular transport: Viral components either hijack the cytoplasmic membrane traffic or they interact directly with the cytoskeletal transport machinery. In this review we describe how viruses--particularly members of the Herpesviridae, Adenoviridae, Parvoviridae, Poxviridae, and Baculoviridae--make use of the microtubule and the actin cytoskeleton. Analysing the underlying principles of viral cytosolic transport will be helpful in the design of viral vectors to be used in research as well as human gene therapy, and in the identification of new antiviral target molecules.

The objective of our treatment trial AML HD93 was to evaluate the impact of different postremission therapies in genetically defined subgroups of acute myeloid leukemia (AML). All patients except those with AML FAB M3 received a double induction therapy with ICE followed by a first consolidation therapy was given according to the HAM protocol. A bone marrow harvest or a peripheral blood progenitor cell collection was performed during hematological reconstitution after the first consolidation. For second consolidation therapy the patients were stratified in three risk groups: Low-risk [t(8;21), abn(16q22), t(15;17)]: HAM; intermediate- risk [normal karyotyp]: allogeneic transplantation (A11oSCT), if an HLA-identical sibling was available, or S-HAM; high-risk [all other abnormalities]: A11oSCT, if an HLA-identical sibling was available, or autologous transplantation (AutoSCT). Between September 1993 and January 1998, 246 patients, aged 16 to 60 years, entered the AML HD93 trial. Complete remission rates after double induction significantly differed between the three risk groups; low-risk: 92%, intermediate-risk: 82%, high-risk: 59%. The overall survival for patients with refractory disease was very poor with 12% at 2 years and all patients, who survived, had received A11oSCT. The disease free survival (DFS) for low, intermediate and high-risk was 67%, 49% and 34% at 2 years, respectively. There was a marked difference in the low-risk group between patients either exhibiting t(8;21) or t(15;17) and those exhibiting abn(16q22) with an DFS of 78% and 44%, respectively. In the high-risk group, patients exhibiting abn(1 1q23) did better than those exhibiting abn(3q), -5/5q-, -7/7q-, abn(12p), abn(17p), and complex karyotypes with a DFS of 38% and 28%, respectively. Based on the results of the AML HD93 trial and on published data from large multicenter study groups, in February 1998 we initiated our new trial AML HD98-A. Two major objectives of this ongoing trial are to evaluate in a randomized manner the impact of AutoSCT compared to HAM in patients exhibiting a normal karyotype and to study the feasibility and efficacy of AlloSCT either from HLA-identical siblings or matched unrelated donors in high-risk patients.

More than half of the cases of acute myeloid leukemia [AML] occur in patients over the age of 60 (Brincker 1985, Stone and Mayer 1993). In contrast to younger patients, AML in the elderly is frequently resistant to chemotherapy and overall outcome remains poor. The probability of entering complete remission [CR] averages 30 to 50%, median diseasefree survival [DFS] is 9 to 12 months, and only 15 to 20% of the patients survive beyond 2 years (Bishop et al 1996, Dombret et al 1995, Lowenberg et al 1997, Mayer et al 1994, Rowe et al 1995, Stone et al 1995, Taylor et al 1995). The inferior prognosis results in part from reduced tolerance of myelosuppressive chemotherapy (Champlin et al 1989, Johnson and Liu Yin 1993, Lowenberg et al 1989, Rees et al 1986, Stone and Mayer 1993, Tilly et al 1990). On the other hand, there are more and more data indicating that AML in the elderly is biologically different from AML in younger patients. The frequency of AML evolving from myelodysplastic syndrome [MDS] increases with age (Aul et al 1992, Foucar et al 1985). Additionally, AML in the elderly is often associated with unfavorable cytogenetic abnormalities (Dastugue et al 1995, Fenaux et al 1989, Leith et al 1997, Schiffer et al 1989, Swansbury et al 1994, Yunis et al 1988) and with a high incidence of intrinsic drug resi stance of the leukemic blasts, mediated by expression of the multidrug resistance glycoprotein MDR1 or alternative mechanisms (Leith et al 1997).

Deletions affecting the long arm of chromosome 6 (6q) are among the most commonly observed chromosomal aberrations in lymphoid malignancies and have been identified as adverse prognostic factor in subsets of tumors. Whereas at least two regions of minimal deletion have been established, one in 6q21-q23 and another in 6q25-q27, no tumor suppressor gene that might be involved in the pathogenesis of lymphoid malignancies has been so far identified from these segments. For B cell chronic lymphocytic leukemia (B-CLL) conflicting data have been reported regarding the incidence and prognostic significance of 6q deletions. In the current study we have used two YAC clones mapping to deletion regions in bands 6q21 and 6q27 as probes for fluorescence in situ hybridization (FISH) in a large series of B-CLL cases to analyze the incidence, localization and clinical significance of 6q aberrations. Among 285 patients with B-CLL studied we identified 21 cases (7%) with 6q deletions. All deletions were found with the probe mapping to 6q21 while the 6q27 region was deleted only in a third of these cases. Analysis of the clinical characteristics and laboratory parameters showed that the patients with 6q deletions had higher white blood cell counts and more extensive lymphadenopathy. However, the overall survival and the treatment-free intervals were similar in the two groups. We conclude that deletions in 6q21 occur in 7% of B-CLL and identify a subgroup of patients characterized by a larger tumor mass but no inferior outcome.

The genetic alterations underlying the pathogenesis of B-cell chronic lymphocytic leukemia (B-CLL) are difficult to assess. Cytogenetic studies are hindered by the low in vitro mitotic activity of the tumor cells and the limited resolution of chromosome banding. Molecular genetic analyses are hampered by nonclonal cells contained in the specimens and by the limited knowledge of candidate genes involved. As a complement to cytogenetic and molecular genetic techniques, fluorescence in situ hybridization (FISH) has proven powerful in the molecular cytogenetic analysis of B-CLL. FISH allows the detection of aberrations such as trisomies, deletions, and translocation breakpoints on the single cell level in dividing as well as non-dividing cells without the prerequisite of detailed physical maps or knowledge of involved genes. As detected by the interphase cytogenetic FISH approach, the most common chromosome abnormalities of B-CLL are deletions in band 13q14, followed by deletions in 11q22-q23, trisomy 12, deletions in 17p13, and deletions in 6q21. Abnormalities in 17p13 seem to involve the TP53 tumor suppressor gene, but as yet no candidate genes have been identified for the other frequent aberrations. Toward the identification of such genes by positional cloning, FISH can be applied for detailed aberration mapping at the molecular level. Furthermore, the accurate detection of chromosome aberrations in B-CLL by FISH provides a valid basis for the evaluation of their prognostic significance. Inactivation of TP53 in 17p13 and deletions in 11q22-q23 have already been shown to be among the most important independent prognostic factors. Genetic abnormalities may eventually provide biological parameters, allowing a risk assessment for individual patients at the time of diagnosis of this clinically heterogeneous disease.

Deletion of the multidrug resistance-associated protein ( MRP1 ) gene in acute myeloid leukemia with inversion of chromosome 16 has no prognostic impact