The biology, pathogenesis and clinical aspects of acute lymphoblastic leukemia in children with Down syndrome.

Children with Down syndrome (DS) are at a 20-fold increased risk for acute lymphoblastic leukemia (DS-ALL). Although the etiology of this higher risk of developing leukemia remains largely unclear, the recent identification of CRLF2 (cytokine receptor like factor 2) and JAK2 mutations and study of the effect of trisomy of Hmgn1 and Dyrk1a (dual-specificity tyrosine phosphorylation-regulated kinase 1A) on B-cell development have shed significant new light on the disease process. Here we focus on the clinical features, biology and genetics of ALL in children with DS. We review the unique characteristics of DS-ALL on both the clinical and molecular levels and discuss the differences in treatments and outcomes in ALL in children with DS compared with those without DS. The identification of new biological insights is expected to pave the way for novel targeted therapies.

Second malignancies after autologous hematopoietic cell transplantation in children.

Childhood autologous hematopoietic cell transplant (auto-HCT) survivors can be at risk for secondary malignant neoplasms (SMNs). We assembled a cohort of 1487 pediatric auto-HCT recipients to investigate the incidence and risk factors for SMNs. Primary diagnoses included neuroblastoma (39%), lymphoma (26%), sarcoma (18%), central nervous system tumors (14%) and Wilms tumor (2%). Median follow-up was 8 years (range, <1-21 years). SMNs were reported in 35 patients (AML/myelodysplastic syndrome (MDS)=13, solid cancers=20, subtype missing=2). The overall cumulative incidence of SMNs at 10 years from auto-HCT was 2.60% (AML/MDS=1.06%, solid tumors=1.30%). We found no association between SMNs risk and age, gender, diagnosis, disease status, time since diagnosis or use of TBI or etoposide as part of conditioning. OS at 5-years from diagnosis of SMNs was 33% (95% confidence interval (CI), 16-52%). When compared with age- and gender-matched general population, auto-HCT recipients had 24 times higher risks of developing SMNs (95% CI, 16.0-33.0). Notable SMN sites included bone (N=5 SMNs, observed (O)/expected (E)=81), thyroid (N=5, O/E=53), breast (N=2, O/E=93), soft tissue (N=2, O/E=34), AML (N=6, O/E=266) and MDS (N=7, O/E=6603). Risks of SMNs increased with longer follow-up from auto-HCT. Pediatric auto-HCT recipients are at considerably increased risk for SMNs and need life-long surveillance for SMNs.

Comparison of native E. coli and PEG asparaginase pharmacokinetics and pharmacodynamics in pediatric acute lymphoblastic leukemia.

Asparaginase (ASP) is used routinely in frontline clinical trials for the treatment of childhood acute lymphoblastic leukemia (ALL). The goals of this study were to assess the pharmacokinetics and pharmacodynamics of ASP and to mathematically model the dynamics between ASP and asparagine (ASN) in relapsed ALL. Forty children were randomized to receive either native or polyethylene glycolated (PEG) Escherichia coli ASP during reinduction therapy. Serial plasma ASP and ASN, cerebrospinal fluid (CSF) ASN, and serum anti-ASP antibody samples were collected. The ASP clearance was higher (P = 0.001) for native vs. PEG ASP. Patients with antibodies to PEG ASP had faster PEG ASP clearance (P = 0.004) than did antibody-negative patients. Patients who were positive for antibodies had higher CSF ASN concentrations than did those who were negative (P = 0.04). The modeling suggests that by modifying dosages, comparable ASN depletion is achievable with both preparations. At relapse, there were significant pharmacokinetic and pharmacodynamic differences attributable to ASP preparation and antibody status.

A multi-center phase I study of clofarabine, etoposide and cyclophosphamide in combination in pediatric patients with refractory or relapsed acute leukemia.

This Phase I study of clofarabine with etoposide and cyclophosphamide for children with relapsed/refractory acute lymphoblastic leukemia (ALL) or acute myelogenous leukemia (AML) was conducted to determine the maximum tolerated dose (MTD), dose-limiting toxicities and the recommended phase 2 doses (RP2Ds). All three drugs were administered for five consecutive days in induction and four consecutive days in consolidation, for a maximum of eight cycles. A total of 25 patients (20 ALL and 5 AML) were enrolled in five cohorts. An MTD was not reached. The RP2Ds of clofarabine, cyclophosphamide and etoposide were 40, 440 and 100 mg/m(2)/day, respectively. Complete remission (CR) was achieved in 10 patients (ALL: nine; AML: one), and CR without platelet recovery in six patients (ALL: two; AML: four) for an overall response rate of 64% (ALL: 55%; AML: 100%). Of the 16 responders, 9 patients proceeded to hematopoietic stem cell transplantation. In conclusion, the combination of clofarabine, etoposide and cyclophosphamide was well tolerated and effective in pediatric patients with relapsed/refractory leukemia. Of note, the phase II portion of the trial was amended after the occurrence of unexpected hepatotoxicity. The ongoing phase II study will evaluate the efficacy and safety of this regimen in ALL patients.

Effective treatment of advanced-stage childhood lymphoblastic lymphoma without prophylactic cranial irradiation: results of St Jude NHL13 study.

There has been a steady improvement in cure rates for children with advanced-stage lymphoblastic non-Hodgkin's lymphoma. To further improve cure rates whereas minimizing long-term toxicity, we designed a protocol (NHL13) based on a regimen for childhood T-cell acute lymphoblastic leukemia, which features intensive intrathecal chemotherapy for central -nervous system-directed therapy and excludes prophylactic cranial irradiation. From 1992 to 2002, 41 patients with advanced-stage lymphoblastic lymphoma were enrolled on the protocol. Thirty patients had stage III and 11 had stage IV disease. Thirty-three cases had a precursor T-cell immunophenotype, five had precursor B-cell immunophenotype and in three immunophenotype was not determined. Out of the 41 patients, 39 (95%) achieved a complete remission. The 5-year event-free rate was 82.9+/-6.3% (s.e.), and 5-year overall survival rate was 90.2+/-4.8% (median follow-up 9.3 years (range 4.62-13.49 years)). Adverse events included two induction failures, one death from typhlitis during remission, three relapses and one secondary acute myeloid leukemia. The treatment described here produces high cure rates in children with lymphoblastic lymphoma without the use of prophylactic cranial irradiation.

Genome-wide microRNA expression profiling in renal cell carcinoma: significant down-regulation of miR-141 and miR-200c.

We investigated expression profiles of microRNA (miRNA) in renal cell carcinoma [clear cell carcinomas (CCC) and chromophobe renal cell carcinomas (ChCC)] and in normal kidneys by using a miRNA microarray platform which covers a total of 470 human miRNAs (Sanger miRBase release 9.1). Unsupervised hierarchical cluster analysis revealed that CCC and ChCC were separable and that no subgroups were identified in CCCs. We found that 43 miRNAs were differentially expressed between CCC and normal kidney, of which 37 were significantly down-regulated in CCC and the other 6 were up-regulated. We also found that 57 miRNAs were differentially expressed between ChCC and normal kidney, of which 51 were significantly down-regulated in ChCC and the other 6 were up-regulated. Together, these observations indicate that expression of miRNAs tends to be down-regulated in both CCC and ChCC compared with normal kidney. We observed that miR-141 and miR-200c were the most significantly down-regulated miRNAs in CCCs. Indeed, in all cases of CCC analysed, both miR-141 and miR-200c were down-regulated in comparison with normal kidney. Microarray data and quantitative RT-PCR showed that these two miRNAs were expressed concordantly. TargetScan algorithm revealed that ZFHX1B mRNA is a hypothetical target of both miR-141 and -200c. We established by quantitative RT-PCR that, in CCCs in which miR-141 and miR-200c were down-regulated, ZFHX1B, a transcriptional repressor for CDH1/E-cadherin, tended to be up-regulated. Furthermore, we found that overexpression of miR-141 and miR-200c caused down-regulation of ZFHX1B and up-regulation of E-cadherin in two renal carcinoma cell lines, ACHN and 786-O. On the basis of these findings, we suggest that down-regulation of miR-141 and miR-200c in CCCs might be involved in suppression of CDH1/E-cadherin transcription via up-regulation of ZFHX1B.

Genome-wide analysis of DNA copy number alterations and gene expression in gastric cancer.

Genomic copy number aberrations (CNAs) are believed to play a major role in the development and progression of human cancers. Although many CNAs have been reported in gastric cancer, their genome-wide transcriptional consequences are poorly understood. In this study, to reveal the impact of CNAs on genome-wide expression in gastric cancer, we analysed 30 cases of gastric cancers for their CNAs by array comparative genomic hybridization (array CGH) and 24 of these 30 cases for their expression profiles by oligonucleotide-expression microarray. We found that with the application of laser microdissection, most CNAs were detected at higher frequency than in previous studies. Notably, gain at 20q13 was detected in almost all cases (97%), suggesting that this may play an important role in the pathogenesis of gastric cancer. By comparing the array CGH data with expression profiles of the same samples, we showed that both genomic amplification and deletion strongly influence the expression of genes in altered genomic regions. Furthermore, we identified 125 candidate genes, consisting of 114 up-regulated genes located in recurrent regions (>10%) of amplification and 11 down-regulated genes located in recurrent regions of deletion. Up-regulation of several candidate genes, such as CDC6, SEC61G, ANP32E, BYSL and FDFT1, was confirmed by immunohistochemistry. Interestingly, some candidate genes were localized at genomic loci adjacent to well-known genes such as EGFR, ERBB2 and SMAD4, and concordantly deregulated by genomic alterations. Based on these results, we propose that our list of candidate genes may contain novel genes involved in the pathogenesis of advanced gastric cancer.

Successive clinical trials for childhood acute myeloid leukemia at St Jude Children's Research Hospital, from 1980 to 2000.

Despite substantial progress in the management of childhood acute myeloid leukemia (AML), only about 50% of patients are cured by intensive chemotherapy. The long-term results of clinical trials may reveal principles that can guide the development of future therapy. From 1980 to 2000, 251 patients <15 years of age with newly diagnosed AML were enrolled on one of the five consecutive St Jude AML studies. The median age of the 128 boys and 123 girls was 6.2 years; 193 were white, 45 black, and 13 of other racial groups. With the exception of one protocol (AML-83), outcomes improved in general over the two decades. The estimated 5-year event-free survival (+/-s.e.) was 30.8+/-5.6% for AML-80; 11.1+/-4.3% for AML-83; 35.9+/-7.4% for AML-87; 43.5+/-6.2% for AML-91; and 45.0+/-11.1% for AML-97. Resistant or relapsed AML caused the great majority of treatment failures. Increasing the intensity of chemotherapy (AML-87) did not improve outcome, partially because of toxicity, nor did prolonging postremission therapy by adding sequential myeloablative (AML-80) or nonmyeloablative (AML-83) chemotherapy cycles. We conclude that subtype-specific therapies are needed to replace the 'one size fits all' strategy of the past two decades.

Overt testicular disease at diagnosis of childhood acute lymphoblastic leukemia: lack of therapeutic role of local irradiation.

To assess the prognosis of overt testicular disease at diagnosis of acute lymphoblastic leukemia, and any therapeutic role of irradiation for this involvement, we reviewed the data of 811 boys treated on St Jude studies Total X--XI (early period) and Total XII-XIV (recent period). In all, 19 boys (2.3%) had testicular disease at diagnosis. In the early period, patients with testicular leukemia had a poorer overall survival (OS) (P=0.003), event-free survival (EFS) (P=0.064), and higher cumulative incidence of relapse (P=0.041) than did other patients. During the recent period, patients with and without overt testicular leukemia did not differ in OS (P=0.257), EFS (P=0.102), or cumulative incidence of relapse (P=0.51). In a multivariate analysis, OS was lower for patients with testicular disease than for those without the involvement in the early period (P=0.047) but not in the recent one (P=0.75). Both patients who received irradiation for residual testicular disease at the end of induction subsequently died of leukemia. Of the other 17 patients who did not receive irradiation, only one developed testicular relapse in combination with bone marrow relapse. In conclusion, the prognostic impact of overt testicular disease has diminished. Irradiation appears to provide no survival advantage to this patient population.

Low-dose oral etoposide-based induction regimen for children with acute lymphoblastic leukemia in first bone marrow relapse.

We evaluated the clinical response to low-dose etoposide in relapsed acute lymphoblastic leukemia (ALL). Of the 45 patients with ALL in first bone marrow relapse enrolled on the ALL R15 protocol, 44 had received epipodophyllotoxins during frontline therapy. In the first week of remission induction therapy, patients received etoposide (50 mg/m(2) per day) administered orally as a single agent once or twice daily. On Day 8, patients started to receive dexamethasone, vincristine, and L-asparaginase. Etoposide was administered until Day 22. Two courses of consolidation therapy were followed by continuation therapy or hematopoietic stem cell transplantation. After 7 days of single-agent etoposide treatment, peripheral blast cell counts (P=0.013) and percentages of bone marrow blasts (P=0.016) were significantly reduced. In all, 38 (84.4%) attained second remission. Only time to relapse was significantly associated with outcome (P=0.025): the 5-year event-free survival estimates (+/-se) were 52.0+/-9.6% for those with late relapse and 20.0+/-8.0% for those with early relapse. We conclude that low-dose etoposide administered orally has a cytoreductive effect in relapsed ALL.

Clinical significance of minimal residual disease in childhood acute lymphoblastic leukemia after first relapse.

Using flow cytometric techniques capable of detecting 0.01% leukemic cells, we prospectively studied minimal residual disease (MRD) in patients with acute lymphoblastic leukemia (ALL) after first relapse. At the end of remission reinduction, 41 patients had a bone marrow sample adequate for MRD studies; 35 of these were in morphologic remission. Of the 35 patients, 19 (54%) had MRD >/=0.01%, a finding that was associated with subsequent leukemia relapse. The 2-year cumulative incidence of second leukemia relapse was 70.2+/-12.3% for the 19 MRD-positive patients and 27.9+/-12.4% for the 16 MRD-negative patients (P=0.008). Among patients with a first relapse off therapy, 2-year second relapse rates were 49.1+/-17.8% in the 12 MRD-positive and 0% in the 11 MRD-negative patients (P=0.014); among those who received only chemotherapy after first relapse, the 2-year second relapse rates were 81.5+/-14.4% (n=12) and 25.0+/-13.1% (n=13), respectively (P=0.004). Time of first relapse and MRD were the only two significant predictors of outcome in a multivariate analysis. We conclude that MRD assays should be used to guide the selection of postremission therapy in patients with ALL in first relapse.

Mouse soluble CD14 truncated at amino acid 71 in transgenic mice: preventive effect on endotoxin-mediated toxic shock.

Mouse soluble CD14 truncated at amino acid 71 (N71) contains the lipopolysaccharide (LPS)-binding sequence. Transgenic mice carrying alpha1-antitrypsin (AT) promoter-N71 fusion genes, designated AT363-1 and AT363-2, were produced. These mice constitutively produced elevated levels of N71. The concentration of LPS in sera after intraperitoneal LPS injection was lower in AT363-1 mice than in nontransgenic mice. The expression of N71 mRNA was enhanced by subcutaneous turpentine oil injection. The levels of serum LPS and tumor necrosis factor-alpha (TNF-alpha) after intraperitoneal LPS injections were lower in AT363-1 mice than in nontransgenic mice. Cell surface TNF-alpha and CD14 expression in exudate peritoneal macrophages prepared by intraperitoneal injection of proteose peptone and then LPS were higher in AT363-1 mice than in nontransgenic mice. Neutrophil infiltration in the liver after induction of the generalized Shwartzman reaction was lower in AT363-1 mice than in nontransgenic mice. Lethality of the Shwartzman reaction was significantly lower in AT363-1 than in nontransgenic mice. These findings suggest that the endotoxin-binding protein (N71) from CD14 prevents endotoxin-mediated toxic shock.

Induction of a novel mechanism of accelerated bacterial clearance by lipopolysaccharide in CD14-deficient and Toll-like receptor 4-deficient mice.

Despite the lack of a proinflammatory response to LPS, CD14-deficient mice clear Gram-negative bacteria (Escherichia coli 0111) at least 10 times more efficiently than normal mice. In this study, we show that this is due to an early and intense recruitment of neutrophils following the injection of Gram-negative bacteria or LPS in CD14-deficient mice; in contrast, neutrophil infiltration is delayed by 24 h in normal mice. Similar results of early LPS-induced PMN infiltration and enhanced clearance of E. coli were seen in Toll-like receptor (TLR) 4-deficient mice. Furthermore, the lipid A moiety of LPS induced early neutrophil infiltration not only in CD14-deficient and TLR-4-deficient mice, but also in normal mice. In conclusion, the lipid A component of LPS stimulates a unique and critical pathway of innate immune responses that is independent of CD14 and TLR4 and results in early neutrophil infiltration and enhanced bacterial clearance.

Transcriptional regulation of the human osteopontin promoter: functional analysis and DNA-protein interactions.

Synthesis of cell attachment proteins and cytokines, such as osteopontin (OPN), can promote tumor cell remodeling of the extracellular matrix into an environment that promotes tumor cell attachment and migration. We investigated the transcriptional regulation of OPN in the U-251MG and U-87MG human malignant astrocytoma cell lines. Deletion and mutagenesis analyses of the OPN promoter region identified a proximal promoter element (-24 to -94 relative to the transcription initiation site) that is essential for maintaining high levels of OPN expression in the tumor cells. This element, designated RE-1, consists of two cis-acting elements, RE-1a (-55 to -86) and RE-1b (-22 to -45), which act synergistically to regulate the activity of the OPN promoter. Gel shift assays using nuclear extracts of U-251MG cells demonstrated that RE-1a contains binding sites for transcription factors Sp1, the glucocorticoid receptor, and the E-box-binding factors, whereas RE-1b contains a binding site for the octamer motif-binding protein (OCT-1/OCT-2). Inclusion of antibodies directed toward Myc and OCT-1 in the gel shift assays indicated that Myc and OCT-1 participate in forming DNA-protein complexes on the RE-1a and RE-1b elements, respectively. Our results identify two previously unrecognized elements in the OPN promoter that act synergistically to promote upregulation of OPN synthesis by tumor cells but are regulated by different transcription factors.

ADAM family proteins in the immune system.

CD156 is a member of a family proteins characterized by a disintegrin and a metalloprotease domain (ADAM). These molecules are phylogenically conserved but have individual roles in a variety of cells. Here, Shunsuke Yamamoto and colleagues discuss data suggesting that ADAM family proteins have important roles in the immune system.

CD14 plays no major role in shock induced by Staphylococcus aureus but down-regulates TNF-alpha production.

Recent in vitro studies have suggested that CD14, a major receptor for LPS, may also be a receptor for cell wall components of Gram-positive bacteria and thus play a role in Gram-positive shock. To analyze the in vivo role of CD14 in responses to Gram-positive bacteria, CD14-deficient and control mice were injected with Staphylococcus aureus, and the effects on lethality, bacterial clearance, and production of cytokines were analyzed. Survival of CD14-deficient and control mice did not differ significantly after administration of various doses of either unencapsulated or encapsulated S. aureus; furthermore, mice in both groups displayed similar symptoms of shock. In addition, inflammatory cytokines such as TNF-alpha and IL-6 were readily detectable in the serum of CD14-deficient mice injected with live or antibiotic-killed S. aureus. Surprisingly, the serum concentration of TNF-alpha in CD14-deficient mice was at least threefold higher than in control mice after injection of either unencapsulated or encapsulated S. aureus, suggesting that CD14 down-regulates TNF-alpha. A similar increase in serum TNF-alpha occurred when CD14-deficient animals were injected with gentamicin-killed bacteria even though no symptoms of shock were observed. These studies indicate that CD14, in contrast to its key function in responses to the Gram-negative bacterium, Escherichia coli 0111, does not play a prominent role in septic shock induced by S. aureus, and that the symptoms of S. aureus shock are not due solely to TNF-alpha.

Lipopolysaccharide structure influences the macrophage response via CD14-independent and CD14-dependent pathways.

CD14, a protein expressed on the surface of monocytes and neutrophils, is a major receptor for lipopolysaccharide (LPS). Studies with normal and CD14-deficient macrophages show that responses to low concentrations of LPS require expression of CD14, whereas responses to high concentrations of LPS are CD14-independent. Since LPS isolated from different bacterial species shows structural variability, studies were performed to determine whether differences in LPS structure influence CD14-dependent and CD14-independent responses. Studies with LPS purified from Escherichia coli, Salmonella abortus subspecies equi, Salmonella minnesota, Pseudomonas aeruginosa, Neisseria meningitidis, Bacteroides fragilis, and Rhodobacter sphaeroides show that the strongest CD14-dependent responses require a typical O-antigen, long carbohydrate chains, at least 6 acyl chains in their lipid A, and 2-phosphorylated Kdo moieties; wild-type LPS lacking a typical O-antigen and containing short carbohydrate chains and 2-phosphorylated Kdo moieties induces the strongest CD14-independent response.

Acute pancreatitis induces cytokine production in endotoxin-resistant mice.

OBJECTIVE: The purpose of this study was to determine whether pathologic progression and cytokine responses in acute pancreatitis (AP) are altered in the absence of endotoxemia. SUMMARY BACKGROUND DATA: Previous studies have demonstrated that AP is characterized by rapid production and release of inflammatory cytokines, which play a major role in the local pancreatic and systemic complications of this disease. Infection and endotoxemia have been implicated as a major source of morbidity and death in AP and as possible stimuli for the overwhelming cytokine response seen in this disease. METHODS: AP was induced by a choline-deficient and ethionine-supplemented diet for 4 days in normal C57BL/6J mice (controls, n = 23) and in CD14 knockout mice (CD14KO, n = 23), which cannot produce circulating cytokines in response to endotoxin. Control and endotoxin-resistant mice were killed at time 0, then at 24, 48, 72, and 96 hours after the start of the diet. At each time point serum was collected for amylase, glucose, and cytokine measurements (tumor necrosis factor-alpha [TNFalpha] and interleukin-1beta [IL1beta]), and the pancreas was removed for histologic examination. TNFalpha was measured with a bioassay using WEHI-2F cells and IL1beta with a bioassay using D10.G4.1 cells. RESULTS: CD14KO mice developed biochemical manifestations of AP with alterations in amylase levels, hypoglycemia, weight loss, and histologic changes of pancreatitis similar to the pattern seen in control mice. TNFalpha and IL1beta production had similar kinetics in both groups, with significant peak TNFalpha serum levels at 72 hours and a progressive rise of IL1beta levels throughout the study period. Histologic changes appeared earlier and were more pronounced in the control versus the CD14KO mice. However, the mortality rate was identical (20% at 96 hours) for both groups. CONCLUSIONS: These results demonstrate that the progression of AP, the cytokine response associated with the disease, and early death are independent of endotoxin action. These findings, which suggest that an uncharacterized stimulus is responsible for triggering the cytokine cascade in this disease, may have significant implications for the management of patients with AP.