Core-binding factor leukemia hijacks the T-cell-prone PU.1 antisense promoter

The blood system serves as a key model for cell differentiation and cancer. It is orchestrated by precise spatiotemporal expression of crucial transcription factors. One of the key master regulators in the hematopoietic systems is PU.1. Reduced levels of PU.1 are characteristic for human acute myeloid leukemia (AML) and are known to induce AML in mouse models. Here, we show that transcriptional downregulation of PU.1 is an active process involving an alternative promoter in intron 3 that is induced by RUNX transcription factors driving noncoding antisense transcription. Core-binding factor (CBF) fusions RUNX1-ETO and CBFβ-MYH11 in t(8;21) and inv(16) AML, respectively, activate the PU.1 antisense promoter that results in a shift from sense toward antisense transcription and myeloid differentiation blockade. In patients with CBF-AML, we found that an elevated antisense/sense transcript and promoter accessibility ratio represents a hallmark compared with normal karyotype AML or healthy CD34+ cells. Competitive interaction of an enhancer with the proximal or the antisense promoter forms a binary on/off switch for either myeloid or T-cell development. Leukemic CBF fusions thus use a physiological mechanism used by T cells to decrease sense transcription. Our study is the first example of a sense/antisense promoter competition as a crucial functional switch for gene expression perturbation by oncogenes. Hence, this disease mechanism reveals a previously unknown Achilles heel for future precise therapeutic targeting of oncogene-induced chromatin remodeling.

Enhanced thrombin generation in plasma of severe thrombocytopenic patients due to rFVIIa

RFVIIa-enhanced thrombin generation has been shown to be dependent on platelets. In previous work we have shown that addition of monocytes and rFVIIa to microparticle free plasma causes a distinct thrombin generation. The aim of our study has been to examine whether there is enough surface provided by microparticles in thrombocytopenic plasma to allow an effect of rFVIIa. Patients, methods: Thrombin generation was measured in platelet rich plasma (PRP) and microparticle free plasma (MFP) of thrombocytopenic haemato-oncological patients with and without addition of rVIIa by means of calibrated automated thrombography. Microparticles were analyzed in PRP by FACS flow cytometry. Results: Microparticle free plasma showed no thrombin generation with or without addition of rFVIIa. Addition of rFVIIa to PRP of thrombocytopenic patients led to a significant shortening of lag time and time to peak in thrombin generation, while ETP and peak remained unchanged. Conclusion: Our results show that even in plasma of severe thrombocytopenic patients enough surface may be provided by microparticles to allow an enhancement of thrombin generation by rFVIIa.

A microRNA-mediated regulatory loop modulates NOTCH and MYC oncogenic signals in B- and T-cell malignancies

Growing evidence suggests that microRNAs facilitate the cross-talk between transcriptional modules and signal transduction pathways. MYC and NOTCH1 contribute to the pathogenesis of lymphoid malignancies. NOTCH induces MYC, connecting two signaling programs that enhance oncogenicity. Here we show that this relationship is bidirectional and that MYC, via a microRNA intermediary, modulates NOTCH. MicroRNA-30a, a member of family of microRNAs that are transcriptionally suppressed by MYC, directly binds to and inhibits NOTCH1 and NOTCH2 expression. Using a murine model and genetically modified human cell lines, we confirmed that microRNA-30a influences NOTCH expression in a MYC-dependent fashion. In turn, through genetic modulation, we demonstrated that intracellular NOTCH1 and NOTCH2, by inducing MYC, suppressed microRNA-30a. Conversely, pharmacological inhibition of NOTCH decreased MYC expression, and ultimately de-repressedmicroRNA-30a. Examination of genetic models of gain and loss of microRNA-30a in diffuse large B-cell lymphoma (DLBCL) and T-acute lymphoblastic leukemia (T-ALL) cells suggested a tumor suppressive role for this microRNA. Finally, the activity of the microRNA-30a-NOTCH-MYC loop was validated in primary DLBCL and T-ALL samples. These data define the presence of a microRNA-mediated regulatory circuitry that may modulate the oncogenic signals originating from NOTCH and MYC.

Reduced-intensity allografting in patients with therapy-related myeloid neoplasms and active primary malignancies

Therapy-related myeloid neoplasms (t-MNs) are severe long-term consequences of cytotoxic treatments for a primary, often, malignant disorder. So far, the majority of patients eligible for transplantation have undergone myeloablative allo haematopoietic SCT (HSCT) as a potentially curative treatment, but it has been associated with high transplantation-related mortality (TRM) rates. In this retrospective study, we analysed the outcome of patients with t-MNs undergoing HSCT with reduced-intensity conditioning (RIC). Of 55 patients, seen at a single centre over a 10-year period, 17 underwent RIC HSCT with related or unrelated donors. The estimated overall survival was 53% at 1 year and 47% at 3 years, and disease-free survival was 47% at 1 year. At 1 year, the cumulative incidence of relapse and TRM were 24% and 30%, respectively. Of five patients with active primary neoplasms who underwent transplantation, two are alive beyond 1 year and show CR of both t-MNs and the primary malignancy. These data indicate that RIC HSCT is an encouraging approach for patients with t-MNs. The issue of primary malignancies not being in remission at the time of transplantation should be explored in further studies.

Therapy-related myeloid neoplasms: pathobiology and clinical characteristics

Therapy-related myeloid neoplasms (t-MNs) are serious long-term consequences of cytotoxic treatments for an antecedent disorder. t-MNs are observed after ionizing radiation as well as conventional chemotherapy including alkylating agents, topoisomerase-II-inhibitors and antimetabolites. In addition, adjuvant use of recombinant human granulocyte-colony stimulating factor may also increase the risk of t-MNs. There is clinical and biological overlap between t-MNs and high-risk de novo myelodysplastic syndromes and acute myeloid leukaemia suggesting similar mechanisms of leukaemogenesis. Human studies and animal models point to a prominent role of genetic susceptibilty in the pathogenesis of t-MNs. Common genetic variants have been identified that modulate t-MN risk, and t-MNs have been observed in some cancer predisposition syndromes. In either case, establishing a leukaemic phenotype requires acquisition of somatic mutations - most likely induced by the cytotoxic treatment. Knowledge of the specific nature of the initiating exposure has allowed the identification of crucial pathogenetic mechanisms and for these to be modelled in vitro and in vivo. Prognosis of patients with t-MNs is dismal and at present, the only curative approach for the majority of these individuals is haematopoietic stem cell transplantation, which is characterized by high transplant-related mortality rates. Novel transplantation strategies using reduced intensity conditioning regimens as well as novel drugs - demethylating agents and targeted therapies - await clinical testing and may improve outcome. Ultimately, individual assessment of genetic risk factors may translate into tailored therapies and establish a strategy for reducing t-MN incidences without jeopardizing therapeutic success rates for the primary disorders.

Loss of RAF kinase inhibitor protein is a somatic event in the pathogenesis of therapy-related acute myeloid leukemias with C-RAF germline mutations

We recently described oncogenic and anti-apoptotic C-RAF germline mutations in patients with therapy-related acute myeloid leukemia (t-AML). Activation of the RAF effector ERK was restricted to transformed cells, suggesting the requirement for cooperating events in leukemogenesis. Western blot analysis of blast cells from patients with C-RAF germline mutations revealed loss of the tumor and metastasis suppressor RAF kinase inhibitor protein (RKIP). Immunohistochemistry of the patients' primary tumors revealed normal RKIP expression levels, indicating that the loss of RKIP is a somatic, t-AML-specific event. In focus formation assays, the oncogenic potential of human mutant C-RAF was strongly influenced by expression levels of RKIP. Although the number of colonies formed by C-RAF(S427G) was significantly increased by RKIP silencing, the opposite was observed after RKIP overexpression. These results show that the loss of RKIP is a functional somatic event in carriers of C-RAF germline mutations, which contributes to the development of t-AML.

Enhanced thrombin generation in plasma of severe thrombocytopenic patients due to rFVIIa

RFVIIa-enhanced thrombin generation has been shown to be dependent on platelets. In previous work we have shown that addition of monocytes and rFVIIa to microparticle free plasma causes a distinct thrombin generation. The aim of our study has been to examine whether there is enough surface provided by microparticles in thrombocytopenic plasma to allow an effect of rFVIIa.

PATIENTS, METHODS

Thrombin generation was measured in platelet rich plasma (PRP) and microparticle free plasma (MFP) of thrombocytopenic haemato-oncological patients with and without addition of rVIIa by means of calibrated automated thrombography. Microparticles were analyzed in PRP by FACS flow cytometry.

RESULTS

Microparticle free plasma showed no thrombin generation with or without addition of rFVIIa. Addition of rFVIIa to PRP of thrombocytopenic patients led to a significant shortening of lag time and time to peak in thrombin generation, while ETP and peak remained unchanged.

CONCLUSION

Our results show that even in plasma of severe thrombocytopenic patients enough surface may be provided by microparticles to allow an enhancement of thrombin generation by rFVIIa.

Iron overload in myelodysplastic syndromes (MDS) - diagnosis, management, and response criteria: a proposal of the Austrian MDS platform

Transfusion-related morbidity is an emerging challenge in chronically transfused patients with low-risk myelodysplastic syndromes (MDS). In these patients, transfusion-induced iron overload may represent a leading medical problem. However, although iron-chelating drugs are available, little is known about optimal diagnostic tools, predisposing factors, and the optimal management of these patients. In the current article, we provide recommendations for the diagnosis, prevention and treatment of iron overload in MDS and propose treatment response criteria. Consensus criteria and resulting recommendations were discussed and formulated by members of the MDS platform of the Austrian Society of Haematology and Oncology in a series of meetings and conferences in 2006 and 2007. These recommendations should facilitate and assist in recognition of iron overload, selection of patients, timing of treatment, drug selection and the measurement of treatment responses.

Evaluation of potential risk factors for early infectious complications after autologous peripheral blood stem cell transplantation in patients with lymphoproliferative diseases

A number of risk factors for the occurrence of neutropaenic fever after haematopoietic stem cell transplantation (HSCT) have been proposed. We were interested in whether these factors remain valid for several early infection-related outcomes when applied to a homogeneous group of patients in uni- and multivariate analyses. Therefore, we analysed 144 consecutive patients with lymphoproliferative disorders receiving autologous peripheral blood HSCT. Variables tested as potential risk factors for the occurrence of fever, documented infection (DI), microbiologically documented infection (MDI) or failure of first-line antimicrobial therapy were sex, conditioning regimen, prolonged neutropaenia, low number of CD34+ cells transplanted, purging, lack of selective gut decontamination, higher age and increased body mass index. In uni- and multivariate analyses, conditioning including total body irradiation was the only risk factor for the occurrence of fever, and neutropaenia >or=10 days was the only factor associated with failure of first-line antimicrobial therapy. None of the variables tested was associated with an increased risk for DI or MDI. This analysis suggests that a number of previously proposed risk factors actually are of minor clinical relevance for early infections in the majority of patients receiving autologous HSCT.

Pulmonary infiltrates in patients with haematologic malignancies: transbronchial lung biopsy increases the diagnostic yield with respect to neoplastic infiltrates and toxic pneumonitis

We retrospectively evaluated 107 fiberoptic bronchoscopies with and without transbronchial lung biopsy (TBLB) in 98 consecutive patients with haematologic malignancies and pulmonary infiltrates. Bronchoalveolar lavage (BAL) was performed in 45 and BAL plus TBLB in 62 procedures. There was no procedure-related severe haemorrhage, pneumothorax or death. Infectious aetiology was identified in 26 of 107 (24%), toxic pneumonitis in 17 of 107 (16%) and neoplastic infiltration in 9 of 107 (8.5%) episodes. Combined BAL and TBLB was significantly superior to BAL alone with respect to the diagnosis of neoplastic infiltrates (p=0.008) and toxic pneumonitis (p<0.001) and should therefore be included in the diagnostic work-up of this patient cohort.

RT-PCR and FISH analysis of acute myeloid leukemia with t(8;16)(p11;p13) and chimeric MOZ and CBP transcripts: breakpoint cluster region and clinical implications

The translocation t(8;16)(p11;p13) is associated with acute myeloid leukemia displaying monocytic differentiation (AML FAB M4/5) and fuses the MOZ (also named MYST3) gene (8p11) with the CBP (also named CREBBP) gene (16p13). Detection of the chimeric RNA fusions has proven difficult; only three studies have described successful amplification of the chimeric MOZ-CBP and CBP-MOZ fusions by reverse transcriptase-polymerase chain reaction (RT-PCR). We analyzed four cases of AML M4/5 with t(8;16)(p11;p13) by RT-PCR and fluorescence in situ hybridization (FISH) and characterized the reciprocal RNA fusions from three cases. We cloned both genomic translocation breakpoints from one case by long-range PCR and successfully applied RT-PCR to monitor minimal residual disease (MRD) between clinical complete remission and relapse. In three cases, the genomic breakpoints occurred in MOZ intron 16 and CBP intron 2. In one case, no fusion transcript was detected. The available data suggest clustering of t(8;16)(p11;p13) breakpoints in these introns leading to reciprocal in-frame MOZ exon 16/CBP exon 3 and in-frame CBP exon 2/MOZ exon 17 chimeric transcripts in the majority of cases. The described RT-PCR strategy may be valuable both for the routine detection of the t(8;16)(p11;p13) as well as for monitoring of MRD in this prognostically unfavorable patient group.

High expression of the sister-chromatid separation regulator and proto-oncogene hSecurin occurs in a subset of myeloid leukaemias but is not implicated in the pathogenesis of aneuploidy

Aneuploidy is considered to play an important role in the pathogenesis of malignancies. We were interested whether abnormalities of the sister-chromatid separation regulator and proto-oncogene hSecurin occurred in myeloid leukaemias, and whether such abnormalities correlated with aneuploidy. The expression of hSecurin was assessed by real-time quantitative PCR in samples from patients with acute myeloid leukaemia (AML, n=70), chronic myeloid leukaemia (CML) in chronic phase (CP, n=20) or blast phase (BP, n=12), and granulocytes as well as mononuclear cells (MNCs) from healthy donors (n=21). Median hSecurin expression in AML with normal karyotypes was not significantly different from AML showing aneuploidy, CML BP or cells from healthy donors. However, hSecurin expression in CML CP was significantly increased compared to AML with normal karyotypes (1.82-fold; P<0.001), CML BP (3.18-fold; P<0.001), MNCs (3.17-fold; P<0.001) and granulocytes (2.69 fold; P<0.001) from healthy donors. Mutations in the coding region of hSecurin were not detected. These results do not support a major role of hSecurin in the development of aneuploidy in myeloid leukaemias. However, high expression of hSecurin may be of pathogenetic relevance in a subset of patients with regard to its potential to stimulate angiogenesis and to interact with the DNA-damage response pathway.

Therapy-related leukemia cutis: case study of an aggressive disorder

Therapy-related leukemia cutis has not yet been described. We report a 55-year-old male who developed aleukemic leukemia cutis 15 months after chemotherapy and radiotherapy for non-Hodgkin's lymphoma. Despite intensive therapy including allogeneic hematopoietic stem cell transplantation, the patient died of progressive disease. Sequence analysis of the TP53 gene and screening for defective DNA mismatch repair revealed no abnormalities. This case demonstrates that therapy-related aleukemic leukemia cutis is an aggressive disorder resistant to conventional antineoplastic treatment approaches. As the number of patients developing therapy-related myelodysplasia or leukemia is increasing, clinicians might be confronted more frequently with atypical, extramedullary presentations of these disorders.

High-risk AML complicated by pulmonary aspergillosis: successful treatment with nonmyeloablative stem cell transplantation and long-term administration of voriconazole

Acute myeloid leukemia (AML) associated with central diabetes insipidus (DI) and chromosomal aberrations is characterised by a very poor prognosis. We present a 28-year-old female with AML FAB M0, preceding DI and cytogenetic abnormalities (monosomy 7 and inversion of chromosome 9). Complete remission was achieved with FLAG after she was refractory to two different induction regimens. Prolonged neutropenia resulted in invasive pulmonary aspergillosis. Allogeneic stem cell transplantation from a matched unrelated donor was performed using a reduced-intensity conditioning regimen. Desmopressin substitution for DI was withdrawn after transplant without recurrence of symptoms. Initial antifungal treatment, including liposomal amphotericin B, caspofungin and itraconazole, was replaced by voriconazole after deterioration of pulmonary aspergillosis, resulting in improvement, stabilisation and finally, also as the combined effect of discontinuation of the immunosuppressive therapy, in disappearance of signs and symptoms. Thirteen months after transplant, the patient is in continuous complete remission. The presented case study thus demonstrates that high-risk AML with concomitant invasive fungal infection may be safely and effectively treated by nonmyeloablative stem cell transplantation and long-term administration of voriconazole.

Acute pseudo-obstruction of the small intestine following high-dose chemotherapy and stem cell support

BACKGROUND

Acute intestinal pseudo-obstruction is a potentially life-threatening disease which is characterized by massive dilation of the colon or small intestine without mechanical obstruction and may develop after surgery or severe illness.

PATIENTS AND METHODS

We report 2 cases in which acute small intestinal pseudo-obstruction occurred after high-dose chemotherapy and autologous stem cell support. In 1 patient explorative abdominal laparoscopy was performed to rule out mechanical ileus. However, after having initiated treatment with acetylcholinesterase inhibitors a prompt small intestinal decompression was observed in both patients.

CONCLUSIONS

Acetylcholinesterase inhibitors should be considered as an early conservative intervention in the treatment of acute intestinal pseudo-obstruction to avoid surgery of patients undergoing high-dose chemotherapy with autologous stem cell support.

Prolonged monitoring of troponin T for the detection of anthracycline cardiotoxicity in adults with hematological malignancies

The study was performed to describe the time course of serum cardiac troponin T (cTnT) elevations for the early detection of anthracycline cardiotoxicity. cTnT was analyzed serially in 78 patients with hematological malignancies receiving 142 treatment cycles including various anthracyclines. cTnT positivity was defined as an increase in cTnT >or=0.03 ng/ml and was observed in 12 patients (15%) during 16 treatment cycles (11%). Peak cTnT levels were observed on day +21.5 (median, range: day +6 to day +35) after initiation of anthracycline therapy. cTnT positivity lasted >or=3 days in 63% of cycles and began to occur after a median of two anthracycline doses. Follow-up echocardiography in 28 patients showed a greater decrease in left ventricular ejection fraction (LVEF) in cTnT-positive patients compared to the cTnT-negative group (10% vs 2%, p=0.017). Age, gender, and pretreatment LVEF had no influence on the occurrence of cTnT positivity. Serial measurement of serum cTnT reveals delayed subclinical myocardial damage even after minor anthracycline exposure, may identify patients at risk for subsequent myocardial dysfunction, and suggests prolonged damage to the cardiac myofibrillar system.

Monitoring of cardiac function by serum cardiac troponin T levels, ventricular repolarisation indices, and echocardiography after conditioning with fractionated total body irradiation and high-dose cyclophosphamide

OBJECTIVES

Highly differing rates of cardiac complications associated with high-dose cyclophosphamide (CY) have been reported, and only one clinical study has been performed on the cardiotoxic effects of CY monotherapy following total body irradiation (TBI).

PATIENTS AND METHODS

We prospectively evaluated the potential cardiotoxic effects of conditioning with fractionated total body irradiation and high-dose cyclophosphamide (TBI/CY) by serial measurement of serum cardiac troponin T (cTnT), assessment of systolic and diastolic echocardiographic parameters and analysis of ventricular repolarisation indices (QT-dispersion and corrected QT-dispersion) in 30 adult patients with haematological malignancies undergoing haematopoietic stem cell transplantation.

RESULTS

There was no evidence of pretreatment cardiac dysfunction in any patient. Although cTnT was determined serially for a median of 14 d after completion of conditioning, no elevated levels were observed. Echocardiographic parameters did not show any significant change at a median follow-up of 5 months except for one patient with evidence of impaired diastolic filling. No significant differences for mean values before and after high-dose CY were noted for ventricular repolarisation indices. Two patients had a significant increase in corrected QT-dispersion after CY without any other signs of cardiotoxicity. Congestive heart failure or arrhythmias were not observed.

CONCLUSIONS

These data suggest that TBI/CY is safe with respect to cardiotoxicity in patients without pre-existing cardiac dysfunction. Hitherto unknown synergistic cardiotoxic effects of CY with other cytostatic drugs may constitute the major pathogenic factor of myocardial dysfunction after high-dose chemotherapy.

Infectious complications after autologous hematopoietic stem cell transplantation: comparison of patients with acute myeloid leukemia, malignant lymphoma, and multiple myeloma

It is yet undetermined whether patients with different hematological malignancies have different propensities to infectious complications after high-dose chemotherapy (HDC) and autologous hematopoietic stem cell transplantation (HSCT). We retrospectively analyzed 136 cycles of HDC and autologous HSCT in 114 patients with acute myeloid leukemia (AML, 24 cycles), non-Hodgkin's lymphoma/Hodgkin's disease (NHL/HD, 55 cycles), and multiple myeloma (MM, 57 cycles) with respect to early infectious complications. Median duration of neutropenia was longer in patients with AML and NHL/HD than in patients with MM (11 days vs 8 days) and after conditioning including total body irradiation (TBI) compared with chemotherapy only preparative regimens (11 days vs 7 days). Fever requiring antimicrobial therapy was observed in 88 percent of cycles, with fever of unknown origin (FUO) accounting for 60 percent of febrile episodes. There was no proven fungal infection, but one case of probable invasive pulmonary aspergillosis. Microbiologically documented infections were seen in 29 percent and clinically documented infections in 11 percent. Response to first-line empirical antibiotic therapy was better for FUO than for documented infections (70 percent vs 40 percent). Patients with TBI as part of their conditioning regimen had more overall infections than patients without TBI (96 percent vs 82 percent). There were no differences with respect to the type or incidence of infections between patients with AML, NHL/HD, and MM. Patients with different hematological malignancies have similar rates of early infectious complications after HDC and autologous HSCT. TBI may be associated with an increased risk for infections in the early post-transplant period.

BAALC, the human member of a novel mammalian neuroectoderm gene lineage, is implicated in hematopoiesis and acute leukemia

The molecular basis of human leukemia is heterogeneous. Cytogenetic findings are increasingly associated with molecular abnormalities, some of which are being understood at the functional level. Specific therapies can be developed based on such knowledge. To search for new genes in the acute leukemias, we performed a representational difference analysis. We describe a human gene in chromosome 8q22.3, BAALC (brain and acute leukemia, cytoplasmic), that is highly conserved among mammals but evidently absent from lower organisms. We characterized BAALC on the genomic level and investigated its expression pattern in human and mouse, as well as its complex splicing behavior. In vitro studies of the protein showing its subcellular localization suggest a function in the cytoskeleton network. Two isoforms are specifically expressed in neuroectoderm-derived tissues, but not in tumors or cancer cell lines of nonneural tissue origin. We show that blasts from a subset of patients with acute leukemia greatly overexpress eight different BAALC transcripts, resulting in five protein isoforms. Among patients with acute myeloid leukemia, those overexpressing BAALC show distinctly poor prognosis, pointing to a key role of the BAALC products in leukemia. Our data suggest that BAALC is a gene implicated in both neuroectodermal and hematopoietic cell functions.

Hepatic veno-occlusive disease in two patients with relapsed acute myeloid leukemia treated with anti-CD33 calicheamicin (CMA-676) immunoconjugate

Monoclonal antibodies recognizing hematopoietic antigens are increasingly being used to target therapy directly at leukemic cells, with the aim of achieving sustained remission with little systemic toxicity. Administration of anti-CD33 calicheamicin immunoconjugate is commonly regarded as being safe, with only moderate systemic non-hematological side effects. We report on two cases of hepatic veno-occlusive disease in heavily pretreated patients presenting with relapsed acute myeloid leukemia (AML). Since significant liver toxicity prevented further specific therapy in both patients, we recommend that antibody therapy with anti-CD33 immunoconjugate should be applied with caution in patients presenting with risk factors for the development of hepatic veno-occlusive disease.

Complete remission of generalized relapsed extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type of the gastrointestinal tract after high-dose chemotherapy and autologous peripheral stem cell transplantation

Due to their homing properties, extranodal marginal zone B-cell lymphoma (MZBL) of mucosa-associated lymphoid tissue (MALT) type remain localized for long periods of time, and therefore have an excellent prognosis. However, if generalization and/or transformation into a diffuse large-cell lymphoma occurs, the prognosis deteriorates and no established treatment concepts are yet available. We report about a 57-year-old female patient with relapsed transformed stage-IV extranodal MZBL of MALT type of the entire gastrointestinal tract who was successfully treated using salvage chemotherapy followed by BEAM conditioning [BCNU 1,3-bis-2-(chloroethyl-1-nitrosourea), etoposide, cytosine arabinoside, and melphalan] and autologous peripheral stem cell transplantation. Follow-up revealed a sustained complete remission for 22 months.

Extramedullary T cell lymphoblastic transformation of chronic myeloid leukaemia successfully treated with matched unrelated donor bone marrow transplantation

Chronic myeloid leukaemia (CML) inevitably terminates in blast crisis (BC) which is of myeloid phenotype in approximately two-thirds and B-lymphoid in one-third of patients. T cell BC is rare and associated with poor prognosis. We describe the case of a 48-year-old woman with extramedullary T cell lymphoblastic transformation. After treatment with combination chemotherapy she achieved a second chronic phase and underwent an allogeneic BMT from an HLA-matched unrelated donor. At 30 months follow-up she is still in complete molecular remission and in good clinical condition. We conclude that unrelated donor BMT should be considered as a therapeutic option for patients with extramedullary BC.

Acute myelofibrosis: multifocal bone marrow infiltration detected by scintigraphy and magnetic resonance imaging

Acute myelofibrosis is a rare, malignant hematological disorder of unknown etiology with an inevitably fatal outcome. Here we present the study of a 63-year-old Caucasian man with acute onset of pancytopenia. Repeated bone marrow biopsies showed dense fibrosis and hypoplastic hematopoiesis raising various differential diagnoses of malignant and nonmalignant conditions. Bone marrow scintigraphy and magnetic resonance imaging (MRI) showed areas suggesting neoplastic infiltration, mainly in both femurs and tibias. Histological examination of a surgical biopsy of the left tibia revealed acute megakaryoblastic leukemia. As the patient refused polychemotherapy, therapy with interferon gamma was initiated but discontinued prematurely because of intolerable side effects. The presented case therefore suggests that the combination of bone marrow scintigraphy and MRI is a valuable diagnostic tool in patients presenting with myelofibrosis of unknown origin.

Adoptive transfer of vitiligo after allogeneic bone marrow transplantation for non-Hodgkin's lymphoma

Vitiligo developed in a 50-year-old man 9 months after allogeneic transplantation from his HLA-identical sister who had had this disease for several years. Our findings suggest adoptive transfer of vitiligo by haematopoietic stem cell transplantation, and lend support to the autoimmune nature of this disease.

Mutational analysis of the DNA mismatch repair gene hMLH1 in myeloid leukaemias

Mutations of the DNA mismatch repair (MMR) gene hMLH1 have recently been linked to the development of some hereditary and sporadic cancers which frequently display widespread microsatellite instability (MSI). Conflicting results regarding the extent of MSI in myeloid leukaemias prompted us to perform mutational analysis of all 19 exons of the hMLH1 gene by polymerase chain reaction-single-stranded conformation polymorphism (PCR-SSCP) and sequence analysis in a total of 133 patients with acute and chronic myeloid leukaemia. Apart from one exonic and one intronic polymorphism, no mutations were detected in any of the samples indicating that the major MMR gene hMLH1 is not involved in the pathogenesis or progression of myeloid malignancies.

[Serous detection of the neuroretina in Waldenström disease. A case report]

BACKGROUND

Waldenstrom's Macroglobulinemia is a monoclonal gammopathy producing pathologic IgM antibodies with increased blood viscosity, platelet dysfunction and retinal hemorrhages. As a complication a serous detachment of the macula is described. The pathogenesis of the serous detachment is still not fully understood.

CASE REPORT

A 73-year-old male patient was presented with Waldenstrom's Macroglobulinemia, a typical hyperviscosity retinopathy and serous detachment of the macula. We performed fluorescein (FA)- and indocyaningreenangiography (ICG) before and three months after chemotherapy. Especially ICG-angiographic findings revealed a serous detachment that was restricted to the posterior pole but showed a fingershaped enlargement to the optic disc.

CONCLUSION

FA- and especially ICG-angiographic findings can help to get more information about the pathogenetic mechanism of serous detachment in Waldenstrom's Macroglobulinemia. Besides toxic alteration of the retinal pigmentepithelium, oncotic and hydrostatic pressure, a pathologic communication between the optic disc, the subarachnoid space and the subretinal space is discussed.

Two case studies of chronic idiopathic neutropenia preceding acute myeloid leukaemia

Chronic idiopathic neutropenia is regarded as a benign disorder without risk of malignant transformation. We present two patients with chronic idiopathic neutropenia who showed disease progression to acute myeloid leukaemia. Sequence analysis of the granulocyte-colony stimulating factor receptor (G-CSFR) gene from leukaemic DNA did not reveal any mutations and microsatellite analysis provided no evidence of microsatellite instability or loss of constitutional heterozygosity. These case studies suggest that chronic idiopathic neutropenia may constitute a preleukaemic condition in some patients. Alterations of the G-CSFR or defective DNA mismatch repair do not appear to be involved in malignant transformation.

ABL amplification in a patient with lymphoid blast crisis of chronic myelogenous leukaemia

Although chronic phase myelogenous leukaemia (CML) is characterised by the Philadelphia (Ph) chromosome leading to a fusion of the BCR and ABL genes, additional genetic alterations involved in blast crisis are poorly understood. We report an at least 15-fold amplification of the ABL oncogene in a 29-year-old male patient with a variant Ph-positive t(19;22)(p13;q11.2) CML who presented in lymphoid blast crisis. Our finding suggests that an amplification of the ABL oncogene might play a part in the appearance of an aggressive phenotype in some cases of CML.

PTEN is inversely correlated with the cell survival factor Akt/PKB and is inactivated via multiple mechanismsin haematological malignancies

PTEN is a novel tumour suppressor gene that encodes a dual-specificity phosphatase with homology to adhesion molecules tensin and auxillin. It recently has been suggested that PTEN dephosphorylates phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3, 4,5)P3], which mediates growth factor-induced activation of intracellular signalling, in particular through the serine-threonine kinase Akt, a known cell survival-promoting factor. PTEN has been mapped to 10q23.3, a region disrupted in several human tumours including haematological malignancies. We have analysed PTEN in a series of primary acute leukaemias and non-Hodgkin's lymphomas (NHLs) as well as in cell lines. We have also examined whether a correlation could be found between PTEN and Akt levels in these samples. We show here that the majority of cell lines studied carries PTEN abnormalities. At the structural level, we found mutations and hemizygous deletions in 40% of these cell lines, while a smaller number of primary haematological malignancies, in particular NHLs, carries PTEN mutations. Moreover, one-third of the cell lines had low PTEN transcript levels, and 60% of these samples had low or absent PTEN protein, which could not be attributed to gene silencing by hypermethylation. In addition, we found that PTEN and phosphorylated Akt levels are inversely correlated in the large majority of the examined samples. These findings suggest that PTEN plays a role in the pathogenesis of haematological malignancies and that it might be inactivated through a wider range of mechanisms than initially considered. The finding that PTEN levels inversely correlate with phosphorylated Akt supports the hypothesis that PTEN regulates PtdIns(3,4,5)P3and suggests a role for PTEN in apoptosis.

Visualization of non-Hodgkin's lymphoma by high dosed somatostatin receptor specific scintigraphy and extended single photon emission tomography

The study aimed to increase the sensitivity of somatostatin receptor (SR) specific scintigraphy for the detection of non-Hodgkin's lymphoma (NHL). Ten selected patients presenting with histologically proven NHL and with 50% to 100% bone marrow involvement were injected with 20 micrograms octreotide labeled with a mean of 254 MBq 111In. The results were recorded with a double head gamma camera by long-time SPET (60 sec per frame, 3 interval) of neck/thorax and abdomen/pelvis. To show bone marrow displacement by lymphoma cells, SPET of the same regions (15 sec per frame, 3 interval) was recorded 3 to 7 days later after i.v. administration of 0.5-1 mg monoclonal anti-granulocyte antibody (Mab 250/183) labeled with a mean of 454 MBq 99mTc. This modality showed a person related sensitivity of 70%, a lesion related sensitivity of 48% (29/60), 60% (22/37) above and 30% (7/23) below the diaphragm. The sensitivity in detecting bone marrow involvement was 10%. Only 80% bone marrow infiltration with lymphoma cells in nodular configuration was shown by In-111-octreotide scintigraphy correlating with cold lesions in the anti-granulocyte scan. There was no false positive result; the smallest lesion correctly identified by SR scintigraphy had with a diameter of 1 cm, the largest lesion missed measured 3.5 cm. In conclusion, doubling the doses of octreotide and radiolabel and extended SPET recording improved to some extent the patient related sensitivity and visualized nodular bone marrow involvement in 10% of patients. The lesion related sensitivity improved mainly above but not below the diaphragm.

Changes in platelet membrane glycoproteins before bone marrow transplantation and after engraftment--a pilot study

Thrombotic complications are observed in patients undergoing bone marrow transplantation despite thrombocytopenia and impaired coagulation due to liver function disturbances. Endothelial cell damage which is involved in the pathogenesis of major transplant related complications like graft-versus-host disease, veno-occlusive disease, sepsis or microangiopathy may be a contributing factor. Little is known about platelet function in bone marrow transplant recipients. In order to study functional alterations in circulating platelets we investigated unstimulated and ADP-stimulated platelets of 10 bone marrow transplant recipients ex vivo by flow cytometry in a pilot study using a panel of monoclonal antibodies to characterize changes in membrane glycoproteins. Samples were collected before and during conditioning and at three timepoints after engraftment. 10 healthy volunteers served as controls. Platelets of bone marrow transplant recipients showed partly a significant, higher expression of surface bound fibrinogen, activated fibrinogen receptor, and glycoprotein Ib as compared to controls. P-selectin, a marker of platelet degranulation was significantly elevated after ADP-induced stimulation at all timepoints compared to controls. Only marginal differences were found for GP IIb/IIIa surface expression. The data point to an increased platelet activation state in bone marrow transplant recipients which might contribute to the thrombotic phenomena observed in these patients.

Successful steroid treatment of idiopathic thrombocytopenic purpura after orthotopic liver transplantation for primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune disease of the liver frequently associated with extrahepatic autoimmune phenomena. Specific antibodies against platelet glycoproteins may play an important role in the pathogenesis of thrombocytopenia associated with PBC. This is the first report of life-threatening idiopathic thrombocytopenic purpura successfully treated with steroids in a 62-yr-old woman 2 yr after liver transplantation for PBC.

Aberrant transcripts of the FHIT gene are expressed in normal and leukaemic haemopoietic cells

Deletions and apparent transcriptional abnormalities of the FHIT gene at 3p14.2 have recently been reported in a wide variety of solid tumours. To determine whether lesions of this gene also occur in leukaemia, we have analysed a total of 97 patients (chronic myeloid leukaemia, CML, in chronic phase or blast crisis, n = 71; de novo acute leukaemia, n = 26) and 16 normal individuals. Intact FHIT transcripts from all cases were amplified using RT-PCR. In addition, smaller size bands that were less intense than the full-length products were amplified from several samples from patients with leukaemia and also from normal leucocytes. Sequencing of the small products revealed that they were derived from FHIT transcripts lacking whole exons. Using single-strand conformation polymorphism analysis, no mutations in the coding sequence were detected in any patient. Furthermore, loss of heterozygosity was not seen in any of 36 informative patients at D3S1300 or D3S1481, markers located within the FHIT locus. We conclude that the FHIT gene and other uncharacterized tumour-suppressor genes at 3p14.2 are unlikely to be involved in the pathogenesis of acute leukaemia or progression of CML from chronic phase to blast crisis. Moreover, low-abundance FHIT transcripts that lack whole exons are not specific to malignant cells and should not be taken as evidence of an abnormality in the absence of demonstrable genomic DNA lesions.

Translocation (3;5)(p26;q13) in a patient with chronic T-cell lymphoproliferative disorder

A 67-year-old patient with large granular lymphocyte (LGL) leukemia is described. At fluorescence-activated cell sorting (FACS) analysis of the peripheral blood, the lymphocytes were positive for CD3, CD4, CD5, CD29, CD45RA, CD57, and TCR alpha/beta and negative for CD7, CD8, CD16, CD56, CD19, CD22, and TCR gamma/delta. Bone marrow histology and immunohistochemistry did not reveal any lymphocyte infiltration. Cytogenetic examination of peripheral blood cultures showed a clone with the karyotype 46,XY,t(3;5)(p26;q13). Molecular analysis revealed rearrangement of the gamma-T-cell-receptor chain. The region 3p25-3p26 which harbors the von Hippel-Lindau tumor suppressor gene and the RAF1 oncogene has been rearranged in a few cases of T-cell leukemia. The translocation in this case has not yet been described and may reflect an alternative mechanism in the pathogenesis of these disorders.