Higher risk for acute childhood lymphoblastic leukaemia in Swedish population centres 1973-94. Swedish Child Leukaemia Group. (41/5352)

A population-based sample of acute childhood leukaemia cases in Sweden 1973-94 was analysed by a geographical information system (GIS) for spatial leukaemia distribution in relation to population density. The annual incidence rate for acute lymphoblastic leukaemia (ALL) was 3.6, and for acute non-lymphoblastic leukaemia (ANLL) 0.7, cases per 100,000 children. Incidence rates in population centres, constituting 1.3% of Sweden's land area and approximately 80% of the population, compared with the rest of Sweden showed a statistically significant excess of ALL [odds ratio (OR) 1.68; 95% confidence interval (CI) 1.44-1.95], but not ANLL (OR 1.13; 95% CI 0.98-1.32). An increasing trend, however not statistically significant, was found for ALL incidence with both increasing population density in parishes and increasing degree of urbanity in municipalities. These findings support the theories that some environmental factors associated with high population density, such as infectious agents, may be of aetiological importance for childhood acute lymphoblastic leukaemia.  (+info)

Phase I and pharmacologic study of 9-aminocamptothecin colloidal dispersion formulation in patients with refractory or relapsed acute leukemia. (42/5352)

PURPOSE: Topoisomerase I inhibitors have shown promising anti leukemic activity in acute myelogenous leukemia (AML) and myelodysplastic syndrome. In this phase I study, we investigated the toxicity profile, pharmacokinetics, and activity of a prolonged continuous infusion schedule of the colloidal dispersion formulation of 9-amino-camptothecin (9-AC/CD) in patients with acute leukemia. PATIENTS AND METHODS: Patients with refractory or relapsed AML, acute lymphocytic leukemia (ALL) or chronic myelogenous leukemia in blastic phase (CML-BP) were included in the study. Eligibility criteria were age greater than 15 years, performance status of 2 or better, creatinine < 1.5 mg/dl, and bilirubin < 1.5 mg/dl. 9-AC/CD was given as a continuous intravenous infusion over seven days every three to four weeks. The starting dose was 0.2 mg/m2/d (1.4 mg/m2/course). Courses were given every three to four weeks according to toxicity and anti leukemic efficacy. This phase I study used the classical 3 + 3 design. The dose was escalated by 50% until grade I toxicity was observed, and then by 30% to 35% until the dose limiting toxicity was defined. At the maximal tolerated dose (MTD), 8 to 10 patients were planned to be treated to better define the toxicity and early-activity profiles. RESULTS: Thirty-nine patients (AML thirty-six patients; ALL two patients; CML-BP one patient), median age 56 years, were treated. Severe mucositis was the dose limiting toxicity; it occurred in three of six patients treated at a dose of 1.6 mg/m2/d. The MTD was defined as 1.4 mg/m2/day by the phase I design. Upon expansion of the number of patients, 3 of 10 patients had grade 4 mucositis and 1 of 10 patients had grade 3 diarrhea. Nausea and vomiting were uncommon. No complete or partial remission was observed in 37 evaluable patients. However, 9-AC/CD exhibited antileukemic activity, as reflected by the finding of marrow hypoplasia on day 14 in 46% of the patients. Average steady-state concentration of 9-AC lactone was close to 10 nmol/l, and the of 9-AC lactone area under curve (AUC) was 1409 +/- 705 nmol/l. hr. CONCLUSION: The MTD of 9-AC/CD given as a seven-day continuous infusion was 1.4 mg/m2/d (9.8 mg/m2/course) in patients with acute leukemia. This represents three to fourfold dose escalation compared with the MTD of 9-AC given as shorter continuous infusion (three days) in patients with solid tumors. Future studies will determine the activity of prolonged administration of 9-AC/CD in patients with better prognosis acute leukemia.  (+info)

Cloning and characterization of the EAP30 subunit of the ELL complex that confers derepression of transcription by RNA polymerase II. (43/5352)

The product of the human oncogene ELL encodes an RNA polymerase II transcription factor that undergoes frequent translocation in acute myeloid leukemia (AML). In addition to its elongation activity, ELL contains a novel type of RNA polymerase II interaction domain that is capable of repressing polymerase activity in promoter-specific transcription. Remarkably, the ELL translocation that is found in patients with AML results in the deletion of exactly this functional domain. Here we report that the EAP30 subunit of the ELL complex has sequence homology to the Saccharomyces cerevisiae SNF8, whose genetic analysis suggests its involvement in the derepression of gene expression. Remarkably, EAP30 can interact with ELL and derepress ELL's inhibitory activity in vitro. This finding may reveal a key role for EAP30 in the pathogenesis of human leukemia.  (+info)

Drug concentration-dependent expression of multidrug resistance-associated protein and P-glycoprotein in the doxorubicin-resistant acute myelogenous leukemia sublines. (44/5352)

The multidrug resistance of cancer cells can be mediated by an overexpression of the human MDR1 and MRP genes, which encode the transmembrane efflux pumps, the 170 kDa P-glycoprotein (Pgp) and the 190 kDa multidrug resistance-associated protein (MRP), respectively. In this study, we investigate which protein is preferentially overexpressed in the function of doxorubicin concentrations in the acute myelogenous leukemia cell line (OCI/AML-2). Multidrug-resistant AML-2 sublines were isolated in doxorubicin concentrations of 20, 100, 250, and 500 ng/ml. MRP was at first expressed at low concentrations of less than 5 x IC50 (100 ng/ml) of doxorubicin followed by the overexpression of Pgp with concentrations of more than 12.5 x IC50 (250 ng/ml) of doxorubicin. In addition, it appeared that increased amounts of MRP and its mRNA in AML-2/DX20 and /DX100 decreased gradually in both AML-2/DX250 and /DX500 overexpressing Pgp. In conclusion, it is thought that the overexpression of MRP or Pgp is dependent upon drug concentrations. It could be implicated that the overexpression of MRP might be negatively related to that of Pgp.  (+info)

The prognostic impact of BCL2 protein expression in acute myelogenous leukemia varies with cytogenetics. (45/5352)

BCL2 protein exerts an antiapoptotic effect on cells and decreases chemosensitivity. To determine whether BCL2 expression is prognostic of patient outcome in acute myelogenous leukemia (AML), we measured its level in 198 newly diagnosed, untreated AML patients by Western blotting using whole-cell lysates from low-density peripheral blood cells. BCL2 expression was not associated with the percentage of blasts (R2 = 0.10), French-American-British classification type, or cytogenetic abnormality. Smoothed martingale residual plots indicated that high BCL2 protein level was an adverse prognostic factor for patients with either favorable or intermediate prognosis cytogenetics [FIPC; inv(16), t(8:21), t(15:17), or diploid or insufficient metaphases] but was a favorable prognostic factor for patients with unfavorable prognosis cytogenetics (UC; -5, -7, +8, 11q23, Ph1, or miscellaneous changes). Patients with FIPC and high BCL2 (highest quartile) had a significantly shorter median survival (78 weeks versus not reached; P = 0.009) than did those with lower (lower three quartiles) levels of BCL2. Among those with UC, as BCL2 level decreased from the fourth quartile to the third or the combined first and second quartiles, the median survival decreased (from 94 to 45 or 17 weeks, respectively; P = 0.003). Lower expression of BCL2 in UC was associated with shorter remission duration (P = 0.05). In multivariate analyses performed using either overall or event-free survival as the end point, for either all patients or within either cytogenetic subgroup, BCL2 level was an independent prognostic factor. Similar analysis revealed that BCL2 level was an independent predictor of remission duration for UC patients as well. These data suggest that BCL2 is involved differently in different types (favorable versus unfavorable) of AML and that therapeutic strategies aimed at modulating BCL2 function may be more likely to work in patients with favorable cytogenetic abnormalities.  (+info)

De novo acute myelogenous leukemia with trilineage myelodysplasia associated with t(8;21)(q22;q22). (46/5352)

We describe a rare case of de novo acute myelogenous leukemia with trilineage myelodysplasia (AML/TMDS) associated with t(8;21)(q22;q22). The patient was admitted to our hospital with leukocytopenia. AML/TMDS was diagnosed by excess myeloblasts and morphological findings of bone marrow. The karyotype revealed 45, X, -Y, t(8;21)(q22;q22) in 17 of 20 analyzed mitoses, and also AML1/MTG8 transcripts were detected by the reverse transcription polymerase chain reaction (RT-PCR) method. The patient achieved a complete remission with a combination chemotherapy of daunorubicin, cytarabine, and prednisolone. This case suggests that t(8;21)(q22;q22) may participate in the pathogenesis of AML/TMDS, although this type is usually found as one of the chromosomal abnormalities in de novo acute myelogenous leukemia (AML) with maturation.  (+info)

Green fluorescent protein as a selectable marker of retrovirally transduced hematopoietic progenitors. (47/5352)

Recombinant retroviruses are most commonly used in hematopoietic stem cell gene therapy trials, but gene transfer efficiency is still inadequate with the present vectors. One approach for overcoming this problem is to develop methods of selecting and enriching the successfully transduced cells. We investigated the feasibility of using the green fluorescent protein (GFP) gene as a selectable marker of hematopoietic cells. When M1 murine leukemia cells were electroporated with GFP expression vectors, a red-shifted mutant (S65T) GFP showed several-fold greater fluorescence than the wild-type GFP and generated readily detectable green light under control of SRalpha or CAG promoter. We then inserted an SRalpha-S65T GFP cassette into the MSCV retrovirus vector and established virus producer cells. Infection of primary murine bone marrow cells resulted in a distinct population with green fluorescence, which was separated by fluorescence-activated cell sorting. The fractionated bright cells gave rise to fluorescent spleen colonies in lethally irradiated mice, while the fluorescence-negative cells yielded only dark colonies. These results indicated that GFP is a faithful marker in gene transfer into hematopoietic progenitor/stem cells, facilitating selection of the transduced cells and tracking of their progeny in vivo.  (+info)

Pseudoaneurysm of the subclavian artery due to Xanthomonas pneumonia in a patient with acute myeloid leukemia: its rupture treated by transcatheter coil embolization. (48/5352)

A 52-year-old male with acute myeloid leukemia developed pseudoaneurysm of the subclavian artery. Pneumonia due to Xanthomonas maltophilia, which was multi-drug resistant, progressed to a lung abscess even under administration of antibiotics. This lung infection contiguous to the left carotid and subclavian arteries was suggested to have caused the pseudoaneurysm of the subclavian artery. The rupture of the aneurysm by penetration to the trachea amounted to about 1,000 ml of bleeding; fortunately the bleeding ceased spontaneously. Nonetheless, an emergency transcatheter coil embolization prevented re-bleeding. Endovascular treatment should be considered especially for aneurysms which develop in patients with underlying diseases.  (+info)