Treatment of newly diagnosed acute promyelocytic leukemia (APL): a comparison of French-Belgian-Swiss and PETHEMA results

All-trans retinoic acid (ATRA) plus anthracycline chemotherapy is the reference treatment of newly diagnosed acute promyelocytic leukemia (APL), whereas the role of cytosine arabinoside (AraC) remains disputed. We performed a joint analysis of patients younger than 65 years included in Programa para el Estudio de la Terapéutica en Hemopatía Maligna (PETHEMA) LPA 99 trial, where patients received no AraC in addition to ATRA, high cumulative dose idarubicin, and mitoxantrone, and APL 2000 trial, where patients received AraC in addition to ATRA and lower cumulative dose daunorubicin. In patients with white blood cell (WBC) count less than 10 x 10(9)/L, complete remission (CR) rates were similar, but 3-year cumulative incidence of relapse (CIR) was significantly lower in LPA 99 trial: 4.2% versus 14.3% (P = .03), although 3-year survival was similar in both trials. This suggested that AraC is not required in APL with WBC count less than 10 x 10(9)/L, at least in trials with high-dose anthracycline and maintenance treatment. In patients with WBC of 10 x 10(9)/L or more, however, the CR rate (95.1% vs 83.6% P = .018) and 3-year survival (91.5% vs 80.8%, P = .026) were significantly higher in APL 2000 trial, and there was a trend for lower 3-year CIR (9.9% vs 18.5%, P = .12), suggesting a beneficial role for AraC in those patients.

Short telomeres and high telomerase activity in T-cell prolymphocytic leukemia

To test the role of telomere biology in T-cell prolymphocytic leukemia (T-PLL), a rare aggressive disease characterized by the expansion of a T-cell clone derived from immuno-competent post-thymic T-lymphocytes, we analyzed telomere length and telomerase activity in subsets of peripheral blood leukocytes from 11 newly diagnosed or relapsed patients with sporadic T-PLL. Telomere length values of the leukemic T cells (mean+/-s.d.: 1.53+/-0.65 kb) were all below the 1st percentile of telomere length values observed in T cells from healthy age-matched controls whereas telomere length of normal T- and B cells fell between the 1st and 99th percentile of the normal distribution. Leukemic T cells exhibited high levels of telomerase and were sensitive to the telomerase inhibitor BIBR1532 at doses that showed no effect on normal, unstimulated T cells. Targeting the short telomeres and telomerase activity in T-PLL seems an attractive strategy for the future treatment of this devastating disease.

Myeloid-related protein 8/14 complex is released by monocytes and granulocytes at the site of coronary occlusion: a novel, early, and sensitive marker of acute coronary syndromes

AIMS: We investigated whether myeloid-related protein 8/14 complex (MRP8/14) expressed by infiltrating monocytes and granulocytes may represent a mediator and early biomarker of acute coronary syndromes (ACS). METHODS AND RESULTS: Immunohistochemistry of coronary thrombi was done in 41 ACS patients. Subsequently, levels of MRP8/14 were assessed systemically in 75 patients with ACS and culprit lesions, with stable coronary artery disease (CAD), or with normal coronary arteries. In a subset of patients, MRP8/14 was measured systemically and at the site of coronary occlusion. Macrophages and granulocytes, but not platelets stained positive for MRP8/14 in 76% of 41 thrombi patients. In ACS, local MRP8/14 levels [22.0 (16.2-41.5) mg/L] were increased when compared with systemic levels [13.4 (8.1-14.7) mg/L, P = 0.03]. Systemic levels of MRP8/14 were markedly elevated [15.1 (12.1-21.8) mg/L, P = 0.001] in ACS when compared with stable CAD [4.6 (3.5-7.1) mg/L] or normals [4.8 (4.0-6.3) mg/L]. Using a cut-off level of 8 mg/L, MRP8/14 but not myoglobin or troponin, identified ACS presenting within 3 h from symptom onset. CONCLUSION: In ACS, MRP8/14 is markedly expressed at the site of coronary occlusion by invading phagocytes. The occurrence of elevated MRP8/14 in the systemic circulation prior to markers of myocardial necrosis makes it a prime candidate for the detection of unstable plaques and management of ACS.

The prognostic significance of cytogenetic aberrations in childhood acute myeloid leukaemia. A study of the Swiss Paediatric Oncology Group (SPOG)

In childhood-onset acute myeloid leukaemia (AML) the clinical value of karyotypic aberrations is now acknowledged, although there is still debate concerning the prognostic significance of some events. To add to this knowledge, cytogenetic analysis was performed on a consecutive series of 84 childhood AML patients diagnosed in Switzerland. A result was obtained for all patients, with 69 (82%) showing a clonal karyotypic aberration. In the remaining 15 (18%), no karyotypic aberration was seen by either conventional or fluorescence in situ hybridisation analyses. The most frequent aberrations observed were t(11q23) (19% of all patients), t(8;21) (12%) and +8 (11%). Except for cytogenetics, no clinical parameter was shown to be significantly associated with outcome. The analysis of individual cytogenetic subgroups demonstrated that aberrations involving chromosome 16q were the strongest predictor of a good prognosis, while +8 and complex karyotypes represented the strongest predictors of a poor prognosis. It was also noteworthy that patients with the rare aberrations of del(11q) (n = 4) and t(16;21)(p11;q22) (n = 3) had a poor outcome. The results support the importance of cytogenetic analysis in childhood AML, but show that further work is required in the classification of the poor prognosis aberrations.

Expression of TCL1 in hematologic disorders

OBJECTIVE: TCL1, MTCP1 and TCL1b are three members of a new family of oncogenes that are expressed in T cell leukemias of ataxia telangiectasia patients (T-PLL, T-CLL). TCL1 is located at 14q32.1 and activated by juxtaposition to the alpha/delta-locus at 14q11 or beta-locus at 7q35 of the T cell receptor during the reciprocal translocations t(14;14)(q11;q32), t(7;14)(q35;q32), or inversion inv(14)(q11;q32). TCL1 encodes a predominantly cytoplasmic protein of 114 aa (14 kD) of unknown function. Recent studies suggest that TCL1 promotes cell survival rather than stimulating cell proliferation, as previously proposed. METHODS: In an attempt to clarify the contexts in which TCL1 is expressed, we investigated TCL1 expression in 114 lymphoma and leukemia patients by Northern blot, RT-PCR and immunohistochemistry. RESULTS: TCL1 expression is restricted to lymphoid cells, and is found in neoplastic (T and B cell neoplasms, and Hodgkin's disease) and nonneoplastic proliferations (reactive lesions). Out of 114 cases, 18 neoplasms of myeloid and 4 cases of epithelial origin were TCL1-negative. In lesions of the lymphoid system, both low- and high-grade lymphomas were found to express TCL1. CONCLUSIONS: We propose that TCL1 expression especially in high-grade B cell non-Hodgkin's lymphomas might interfere with B cell differentiation and promote the transition from low- to high-grade lymphoma.

HIC1 tumour suppressor gene is suppressed in acute myeloid leukaemia and induced during granulocytic differentiation

A hallmark of acute myeloid leukaemia (AML) is a block in differentiation caused by deregulated gene expression. The tumour suppressor Hypermethylated In Cancer 1 (HIC1) is a transcriptional repressor, which is epigenetically silenced in solid cancers. HIC1 mRNA expression was found to be low in 128 patient samples of AML and CD34+ progenitor cells when compared with terminally differentiated granulocytes. HIC1 mRNA was induced in a patient with t(15;17)-positive acute promyelocytic leukaemia receiving all-trans retinoic acid (ATRA) therapy. We therefore investigated whether HIC1 plays a role in granulocytic differentiation and whether loss of function of this gene might contribute to the differentiation block in AML. We evaluated HIC1 mRNA levels in HL-60 and U-937 cells upon ATRA-induced differentiation and in CD34+ progenitor cells after granulocyte colony-stimulating factor-induced differentiation. In both models of granulocytic differentiation, we observed significant HIC1 induction. When HIC1 mRNA was suppressed in HL-60 cells using stably expressed short hairpin RNA targeting HIC1, granulocytic differentiation was altered as assessed by CD11b expression. Bisulphite sequencing of GC-rich regions (CpG islands) in the HIC1 promoter provided evidence that the observed suppression in HL-60 cells was not because of promoter hypermethylation. Our findings indicate a role for the tumour suppressor gene HIC1 in granulocytic differentiation. Low expression of HIC1 may very well contribute to pathogenic events in leukaemogenesis.

A pedigree with autosomal dominant thrombocytopenia, red cell macrocytosis, and an occurrence of t(12:21) positive pre-B acute lymphoblastic leukemia

Sampling and analyzing new families with inherited blood disorders are major steps contributing to the identification of gene(s) responsible for normal and pathologic hematopoiesis. Familial occurrences of hematological disorders alone, or as part of a syndromic disease, have been reported, and for some the underlying genetic mutation has been identified. Here we describe a new autosomal dominant inherited phenotype of thrombocytopenia and red cell macrocytosis in a four-generation pedigree. Interestingly, in the youngest generation, a 2-year-old boy presenting with these familial features has developed acute lymphoblastic leukemia characterized by a t(12;21) translocation. Tri-lineage involvement of platelets, red cells and white cells may suggest a genetic defect in an early multiliear progenitor or a stem cell. Functional assays in EBV-transformed cell lines revealed a defect in cell proliferation and tubulin dynamics. Two candidate genes, RUNX1 and FOG1, were sequenced but no pathogenic mutation was found. Identification of the underlying genetic defect(s) in this family may help in understanding the complex process of hematopoiesis.

PU.1 binding to the p53 family of tumor suppressors impairs their transcriptional activity

The transcription factor PU.1 is essential for terminal myeloid differentiation, B- and T-cell development, erythropoiesis and hematopoietic stem cell maintenance. PU.1 functions as oncogene in Friend virus-induced erythroleukemia and as tumor suppressor in acute myeloid leukemias. Moreover, Friend virus-induced erythroleukemia requires maintenance of PU.1 expression and the disruption of p53 function greatly accelerates disease progression. It has been hypothesized that p53-mediated expression of the p21(Cip1) cell cycle inhibitor during differentiation of pre-erythroleukemia cells promotes selection against p53 function. In addition to the blockage of erythroblast differentiation provided by increased levels of PU.1, we propose that PU.1 alters p53 function. We demonstrate that PU.1 reduces the transcriptional activity of the p53 tumor suppressor family and thus inhibits activation of genes important for cell cycle regulation and apoptosis. Inhibition is mediated through binding of PU.1 to the DNA-binding and/or oligomerization domains of p53/p73 proteins. Lastly, knocking down endogenous PU.1 in p53 wild-type REH B-cell precursor leukemia cells leads to increased expression of the p53 target p21(Cip1).

Fatal adenovirus hepatitis during maintenance therapy for childhood acute lymphoblastic leukemia

Disseminated adenoviral infection with hepatitis is rare in children undergoing standard chemotherapy. We report on a 3(1/2)-year-old male with fatal adenovirus hepatitis receiving maintenance chemotherapy for acute lymphoblastic leukemia (ALL). Adenoviral hepatitis was proven by histology, viral culture, and PCR in a liver biopsy. Quantitative real-time PCR in the peripheral blood showed adenoviral DNA copy number >10(9)/ml. Despite aggressive supportive care and antiviral treatment with cidofovir, the patient died rapidly due to fulminant liver failure. Diagnostic and treatment options for adenovirus infection remain unsatisfactory for these patients. We propose suggestions for diagnosis and therapy.

Obesity in long-term survivors of childhood acute lymphoblastic leukemia

BACKGROUND: Childhood acute lymphoblastic leukemia (ALL) with current cure rates reaching 80% emphasizes the necessity to determine treatment related long-term effects. The present study examines the prevalence of and the risk factors for overweight and obesity in a cohort of ALL survivors treated and living in the French speaking part of Switzerland. METHODS: In this retrospective two-center study, height and weight of 54 patients diagnosed with ALL in first complete remission and treated with chemotherapy only were recorded at specified time points during treatment and off-therapy. Body mass index (BMI) and its age- and gender-adjusted standard deviation score (BMI-SDS) were calculated for the patients and their parents separately. Overweight and obesity were defined by a threshold of BMI-SDS >1.645 and BMI-SDS >1.96, respectively. RESULTS: At last follow-up, 16 (30%) of the 54 survivors were overweight and 10 (18%) were obese. The off-treatment period was most at risk with 11 of the 16 becoming overweight and 9 of the 10 becoming obese during that period. Overweight/obesity at diagnosis and abnormal maternal BMI were significantly associated with abnormal weight at follow-up, while age at diagnosis, gender, cumulative dose of steroids and paternal BMI showed no association. CONCLUSIONS: Consistent with published evidence from other regions of the developed and developing world, there is a significant prevalence of obesity in young ALL survivors in the French speaking part of Switzerland. Factors significantly associated with this late effect were mostly related to the familial background rather than to the treatment components.

Non-classical karyotypic features in relapsed childhood B-cell precursor acute lymphoblastic leukemia

Karyotype analysis of acute lymphoblastic leukemia (ALL) at diagnosis has provided valuable prognostic markers for treatment stratification. However, reports of cytogenetic studies of relapsed ALL samples are limited. We compared the karyotypes from 436 nonselected B-cell precursor ALL patients at initial diagnosis and of 76 patients at first relapse. We noticed a relative increase of karyotypes that did not fall into the classic ALL cytogenetic subgroups (high hyperdiploidy, t(12;21), t(9;22), 11q23, t(1;19), <45 chromosomes) in a group of 29 patients at relapse (38%) compared to 130 patients at presentation (30%). Non-classical cytogenetic aberrations in these 29 patients were mostly found on chromosomes 1, 2, 7, 9, 13, 14, and 17. We also describe six rare reciprocal translocations, three of which involved 14q32. The most frequent abnormalities were found in 9p (12/29 cases) and were associated with a marked decrease in the duration of the second remission, but not of the probability of 10-year event-free survival after relapse treatment. From 29 patients with non-classical cytogenetic aberrations, only 8 (28%) had been stratified to a high risk-arm on the first treatment protocol, suggesting that this subgroup might benefit from the identification of new prognostic markers in future studies.

TRAIL mediated signaling in human mast cells: the influence of IgE-dependent activation

BACKGROUND: Mast cells activation through FcepsilonRI cross-linking has a pivotal role in the initiation of allergic reactions. The influence of this activation on programmed cell death of human mast cells has not yet been clarified. This study evaluates the influence of IgE-dependent activation alone and in synergy with TRAIL on the expression of molecules involved in the apoptotic signal transduction. METHODS: Human cord blood derived mast cells (CBMC) were cultured with myeloma IgE followed by activation with anti-human IgE. The expression of proteins involved in apoptotic signal transduction was assessed by immunoblot analysis. To test the effect of activation on a pro-apoptotic stimulus, activated, IgE-treated and resting CBMC were incubated with TRAIL, or in a medium with suboptimal concentrations of stem cell factor (SCF). RESULTS: In accordance with a previous study of ours, it was found that IgE-dependent activation increased TRAIL-induced caspase-8 and caspase-3 cleavage. However, it did not have a significant influence on CBMC death induced by SCF withdrawal. IgE-dependent activation increased the expression of FLIP and myeloid cell leukemia 1 (MCL-1) anti-apoptotic molecules as well as the pro-apoptotic one, BIM. In addition, a decrease in BID expression was observed. TRAIL could reverse the increase in FLIP but did not influence the upregulation of MCL-1 and of BIM. CONCLUSIONS: These findings suggest that IgE-dependent activation of human mast cells induces an increase in both pro-survival and pro-apoptotic molecules. We therefore hypothesized that IgE-dependent activation may regulate human mast cell apoptosis by fine-tuning anti-apoptotic and pro-apoptotic factors.