Hematopoietic stem cell transplantation from HLA-matched sibling donors in children with acute lymphoblastic leukemia: A report from the Children’s Cancer Hospital Egypt

Introduction

Allogeneic hematopoietic stem cell transplantation (HSCT) is widely used for high-risk acute lymphoblastic leukemia (ALL) patients in their first complete remission (CR1), and for relapsed patients in second complete remission (CR2).

Patients and methods

We retrospectively analyzed data for 67 children with ALL, from a cancer center in a low/middle income country, who had undergone HSCT from human leukocyte antigen (HLA)-matched sibling donors (MSDs) using myeloablative conditioning (MAC) regimens, between 2007 and 2020, describing the survival outcome and relapse probability after achieving CR1 and CR2 and determining outcome differences in relation to indications for HSCT in patients transplanted in CR1. All patients had achieved a negative minimal residual disease prior to transplant (<0.01%).

Results

Forty-six patients (68.7%) were in CR1; 25 had adverse cytogenetics, including 18 patients with Philadelphia chromosome-positive ALL (Ph-positive ALL), and 21 had poor induction response. The 5-year overall survival (OS), event-free survival (EFS) and cumulative incidence of relapse (CIR) for the whole cohort were 56.1% (95% CI, 42.8%-69.4%), 49% (95% CI, 35.7%-62.3%) and 33.5% (95% CI, 21.7%-45.8%), respectively with better EFS and CIR for CR1 transplants compared to CR2 transplants (P=0.02 and P=0.03, respectively). Patients with Ph-positive ALL had better 5-year OS, EFS and non-relapse mortality (NRM) compared with other CR1 transplants (P=0.015, P=0.009 and P=0.028, respectively).

Conclusion

Hematopoietic stem cell transplantation from MSD for ALL in CR1 group had superior outcomes compared to CR2 group and was apparently a curable option for Ph-positive ALL without an increased risk of non-relapse mortality. Poorer survival rates and higher relapse probabilities were associated with HSCT conducted to patients who had a poor response to induction therapy or suffered a relapse.

Overexpression of cancerous inhibitor of PP2A (CIP2A) in acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy. Protein phosphatase 2A Protein phosphatase 2A (PP2A) is a major serine/threonine phosphatase and tumor suppressor that negatively regulates numerous signal transduction pathways. Cancerous inhibitor of PP2A (CIP2A) is an endogenous inhibitor of PP2A. CIP2A overexpression was shown to be a recurrent event in cytogenetic normal AML patients. The aim of the study is to evaluate the prognostic significance of CIP2A overexpression in patients with AML.

RESEARCH DESIGN AND METHODS

The study included 174 newly diagnosed cytogenetic normal AML patients. Detection of CIP2A expression was performed using quantitative real-time PCR.

RESULTS

CIP2A was overexpressed in 125/174 (71.8%) of patients. Correlation of CIP2A overexpression with other prognostic factors showed significant association with CD34 expression (p=0.04). CIP2A overexpression was significantly associated with a lower rate of (complete remission) CR (p=0.019) and shorter disease free survival (DFS) and overall survival (OS) (p<0.001 and <0.001, respectively). In multivariate analysis, CIP2A overexpression was an independent adverse prognostic factor that negatively affected DFS and OS (p<0.001, HR:2.8,95%CI:1.7-4.7 and p=0.002, HR:1.8; 95%CI:1.2-2.65, respectively).

CONCLUSION

CIP2A overexpression is a useful prognostic marker in AML.

Characterization of CRLF2 Expression in Pediatric B-Cell Precursor Acute Lymphoblastic Leukemia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is a heterogeneous disease with several underlying genetic ab-normalities. Several studies have tried to elucidate the prognostic significance of cytokine receptor-like factor 2 (CRLF2) overexpression in pediatric B-cell precursor (BCP)-ALL; however, it is still controversial.

METHODS

CRLF2 expression was assessed by flow cytometry in 87 newly diagnosed BCP-ALL pediatric patients, and 80 age and gender-matched control group. Janus Kinase2 (JAK2) (R683) mutation analysis was also performed in those identified to have CRLF2 overexpression with adequate DNA samples by direct sequencing.

RESULTS

CRLF2 overexpression was identified in 26/87 (29.9%) of our patients with cutoff set at mean fluorescence intensity (MFI = 3.8) using the Receiver Operating Characteristic (ROC) curve. There were no significant differences in the clinical and laboratory features between patients with high and low-CRLF2 expression, apart from thrombocytopenia which showed statistically significant association with the low-expression group (p = 0.041). Sequence analysis of samples with high CRLF2 expression (n = 23) revealed that 2/23 (8.7%) cases harbored the mutation JAK2 (R683). CRLF2 levels did not have a significant impact on either overall survival (OS) or disease free survival (DFS) (p = 0.601; p = 0.212, respectively).

CONCLUSIONS

CRLF2 overexpression was not an adverse parameter in pediatric BCP-ALL patients. However, patients with CRLF2 overexpression may harbor the JAK2 mutation presenting a group that can benefit from targeted therapy by kinase inhibitors. The usage of CRLF2 expression to monitor minimal residual disease of BCP-ALL would be an area of interest for further evaluation.

Outcomes of allogenic hematopoietic cell transplantation for childhood chronic myeloid leukemia: Single-center experience

BACKGROUND/OBJECTIVES

Despite the apparent efficacy and favorable toxicity profile of TKIs, allogeneic SCT remains the only curative treatment for CML especially in younger patients, but TRM should be considered. We evaluated the clinical outcomes of pediatric CML patients who had SCT in our center.

METHODS

This retrospective study included children with CML, who received an allogeneic SCT at Children Cancer Hospital Egypt, 57357, from 2007 to 2017. All patients received myeloablative conditioning chemotherapy containing busulfan/cyclophosphamide followed by stem cell infusion from MRD.

RESULTS

From 121 patients diagnosed with CML, 43 had available MRD and subjected to HSCT while 78 patients continued TKI therapy. The median time to transplant from diagnosis was 13 months. At initial diagnosis, there were 39 patients in CP and 4 had blastic crises. Bone marrow harvest was the stem cell source in 32 patients, while 11 cases received mobilized peripheral blood stem cells with average stem cell dose of 4.45 × 10⁶ /kg. The probabilities of overall survival and event-free survival at 5 years were 97.4% and 79.8%, respectively. TRM at 100 days and TRM at 1-year post-transplant were 0%. The incidence of chronic GVHD was significantly higher in peripheral blood than bone marrow stem cell source (P = .004).

CONCLUSION

Considering the excellent survival rates and very low TRM, HSCT is still a valid option for pediatric patients with newly diagnosed CML with best using marrow stem cell source to avoid a significant risk of cGVHD and its related complications.

Outcome of Childhood Acute Myeloid Leukemia With FLT3-ITD Mutation: The Experience of Children's Cancer Hospital Egypt, 2007-17

INTRODUCTION

The presence of FMS-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD) mutation in pediatric acute myeloid leukemia (AML) is associated with high rates of induction failure and worse survival. Its presence places the patient into a high-risk group. We aimed to describe the outcome of pediatric AML with FLT3-ITD mutation.

PATIENTS AND METHODS

We performed a retrospective analysis of cases of AML from July 2007 till July 2017 at Children's Cancer Hospital Egypt.

RESULTS

Seventy-one patients had FLT3 gene mutation out of 687 patients with AML. Sixty-five patients had FLT3 gene mutation with allelic ratio > 0.4; 43 (66.1%) of 65 patients experienced complete remission (CR). Of the 43 patients, 16 patients maintained CR, 18 patients relapsed after first CR, 8 patients died, and 1 patient was lost to follow-up. Patients with relapsing disease died after salvage chemotherapy, except for one patient, who was alive after second CR. Allogeneic bone marrow transplantation (allo-BMT) was performed for 9 (13.8%) of 65 patients in first CR, of whom 8 were alive and in CR, and 1 patient experienced disease relapse and died. Seven patients (10.7%) were alive without allo-BMT. Three years' overall and event-free survival for patients with FLT3-ITD mutation with high allelic ratio was 26.9% and 22.8%, respectively. Three years' overall and event-free survival for patients treated with allo-BMT was 77.8% and 78.8%, respectively, versus patients treated without allo-BMT, 16.3% and 12.8%, respectively.

CONCLUSION

FLT3-ITD mutation in pediatric AML was associated with poor treatment outcomes, and the survival of relapsing patients was extremely poor. Allo-BMT in first remission was the best treatment option. Alternative donor transplants and FLT3 inhibitors are needed to improve outcome in developing countries.

Low expression of miR-204 is associated with expression of CD34 and poor performance status in denovo AML

INTRODUCTION

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. There is growing evidence that microRNAs (miRNAs) provide prognostic information in AML. MiR-204 has a tumor suppressor function, and several studies have proven its role in solid cancers. The aim of this work is to evaluate the level of expression of miR-204 in adults newly diagnosed with AML with normal karyotype and to correlate its level of expression with disease outcome and different prognostic factors.

PATIENTS AND METHODS

The study included 87 adult patients newly diagnosed with AML. Detection of miR-204 was done using RT-PCR in patients and seven age-matched controls.

RESULTS

Acute myeloid leukemia patients showed significantly lower miR-204 expression, compared to control group (P = .029). Low miR-204 expression was significantly associated with positive CD34 (P = .017), with poor performance status (PS) (P = .009), and with the presence of diabetes mellitus (DM) (P = .014). Low expression of miR-204 was also significantly associated with shorter overall survival (OS) (P = .020) and disease-free survival (DFS) (P = .013). Low miR-204 expression was identified as an independent prognostic factor for prediction of shorter OS (P = .034) and DFS (P = .027) in AML.

CONCLUSION

To the best of our knowledge; this is the first time to prove the correlation between miR-204 expression and CD34 expression. Further study of this correlation is needed to confirm the role of miR-204 in CD34-positive cells, including leukemic stem cells. This correlation may have therapeutic implications. MiR-204 can be used as a biomarker for PS in AML patients.

RAS Pathway Mutation Patterns in Patients With Juvenile Myelomonocytic Leukemia: A Developing Country Single-center Experience

INTRODUCTION

Juvenile myelomonocytic leukemia (JMML) is a rare clonal myelodysplastic/myeloproliferative neoplasm of early childhood. Historically, it was difficult to diagnose clinically, as patients present with manifestations shared with other hematologic malignancies or viral infections. It is now clear that JMML is a disease of hyperactive RAS signaling.

PATIENTS AND METHODS

We examined the bone marrow of 41 Egyptian children with JMML by direct sequencing for mutations in the RAS pathway genes.

RESULTS

Mutations were detected in 33 (80%) of 41 patients. We identified 12 (29%) of 41 patients with PTPN11 mutation; 18 (44%) of 41 with RAS mutation; 9 (22%) of 41 with NRAS mutation; 9 (22%) of 41 with KRAS mutation; and 3 (7%) of 41 with CBL mutation. Eleven (92%) of the PTPN11 mutations were detected in exon 3 and 1 (8%) in exon 13. Seven of the NRAS mutations were in exon 2, and 2 were in exon 3. All KRAS mutations were in exon 2. The 3 cases with CBL mutation were homozygous mutations in exon 8. All the mutations detected in PTPN11, NRAS/KRAS, and the CBL genes were previously reported missense mutations in JMML.

CONCLUSION

Our results demonstrate that Egyptian children diagnosed with JMML have high frequency of NRAS/KRAS mutations and lower frequency of PTPN11 mutations as compared with previous studies. The concept of mutually exclusive RAS pathway mutations was clearly observed in our patients. All cancer centers in our region should start implementing molecular diagnostic methods before confirming the diagnosis of JMML and before offering hematopoietic stem cell transplantation.

HLA Haplotypes In 250 Families: The Baylor Laboratory Results And A Perspective On A Core NGS Testing Model For The 17th International HLA And Immunogenetics Workshop

Since their inception, the International HLA & Immunogenetics Workshops (IHIW) served as a collaborative platform for exchange of specimens, reference materials, experiences and best practices. In this report we present a subset of the results of human leukocyte antigen (HLA) haplotypes in families tested by next generation sequencing (NGS) under the 17th IHIW. We characterized 961 haplotypes in 921 subjects belonging to 250 families from 8 countries (Argentina, Austria, Egypt, Jamaica, Germany, Greece, Kuwait, and Switzerland). These samples were tested in a single core laboratory in a high throughput fashion using 6 different reagents/software platforms. Families tested included patients evaluated clinically as transplant recipients (kidney and hematopoietic cell transplant) and their respective family members. We identified 486 HLA alleles at the following loci HLA-A, -B, -C, -DRB1, -DRB3, -DRB4, -DRB5, -DQA1, -DQB1, -DPA1, -DPB1 (77, 115, 68, 69, 10, 6, 4, 44, 31, 20 and 42 alleles, respectively). We also identified nine novel alleles with polymorphisms in coding regions. This approach of testing samples from multiple laboratories across the world in different stages of technology implementation in a single core laboratory may be useful for future international workshops. Although data presented may not be reflective of allele and haplotype frequencies in the countries to which the families belong, they represent an extensive collection of 3rd and 4th field resolution level 11-locus haplotype associations of 486 alleles identified in families from 8 countries.

Serum RANKL, osteoprotegerin (OPG) and RANKL/OPG ratio in children with systemic lupus erythematosus

Background

Systemic lupus erythematosus (SLE) patients have lower bone mineral density (BMD) compared with healthy individuals because of general, genetic, disease and medication-related factors. The disturbance of the receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG) ratio has been reported to be associated with low BMD in many disorders in adults and children alike.

Objectives

The objectives of this study were (i) to assess serum OPG, RANKL and RANKL/OPG ratio levels in SLE children and controls, (ii) to determine whether the cumulative glucocorticoid (CGCS) dose had any effect on the concentration of serum RANKL, OPG and RANKL/OPG ratio, and (iii) to determine the relation of these parameters to BMD.

Methods

We evaluated 50 SLE children and 50 age- and sex-matched healthy controls. RANKL and OPG were assessed in serum and compared between patients and controls. For SLE patients, a univariate followed by multivariable analysis were carried out to detect the possible predictors of the changes in RANKL, OPG and RANKL/OPG ratio levels. Lumbar BMD for all patients was assessed by dual-energy X-ray absorptiometry (DXA) scan and then correlated to different probable correlated factors.

Results

RANKL, OPG and RANKL/OPG ratio were significantly higher in SLE patients ( p ≤ 0.001). Univariate analysis showed significant correlations of RANKL with CGCS ( p ≤ 0.001) and with DXA scan z-score ( p = 0.007): OPG was significantly correlated to Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) score ( p = 0.001) and anti-double-stranded DNA ( p = 0.001), whereas RANKL/OPG was significantly correlated to duration of illness and DXA z-score ( p = 0.002). The multivariable analysis showed that DXA z-score was an independent predictor of RANKL and RANKL/OPG ratio ( p = 0.019 and 0.008, respectively), whereas SLEDAI score was an independent predictor of OPG levels. BMD was negatively correlated to disease duration ( p = 0.008) and CGCS dose ( p = 0.015), but no significant correlation has been found between BMD and cumulative SLEDAI score ( p = 0.29).

Conclusions

Serum RANKL/OPG ratio is elevated in Egyptian children with SLE and is considered a risk factor for reduced bone mass in these children. Other risk factors for low BMD include high CGCS dose and disease duration, supporting that osteoporosis in SLE is multifactorial.

The periodontal stem/progenitor cell inflammatory-regenerative cross talk: A new perspective

Adult multipotent stem/progenitor cells, with remarkable regenerative potential, have been isolated from various components of the human periodontium. These multipotent stem/progenitor cells include the periodontal ligament stem/progenitor cells (PDLSCs), stem cells from the apical papilla (SCAP), the gingival mesenchymal stem/progenitor cells (G-MSCs), and the alveolar bone proper stem/progenitor cells (AB-MSCs). Whereas inflammation is regarded as the reason for tissue damage, it also remains a fundamental step of any early healing process. In performing their periodontal tissue regenerative/reparative activity, periodontal stem/progenitor cells interact with their surrounding inflammatory micro-environmental, through their expressed receptors, which could influence their fate and the outcome of any periodontal stem/progenitor cell-mediated reparative/regenerative activity. The present review discusses the current understanding about the interaction of periodontal stem/progenitor cells with their surrounding inflammatory micro-environment, elaborates on the inflammatory factors influencing their stemness, proliferation, migration/homing, differentiation, and immunomodulatory attributes, the possible underlying intracellular mechanisms, as well as their proposed relationship to the canonical and noncanonical Wnt pathways.

Detection of KIT mutations in core binding factor acute myeloid leukemia

We have investigated the frequency and the effect of KIT mutations on the outcome of patients with CBF-AML. 69 patients (34 pediatrics and 35 adults) with CBF-AML were enrolled in the study. The frequency of KIT mutations was higher in adults compared to pediatrics (22.9% and 14.7%, p = 0.38) respectively. Leukocytosis ≥ 20 × 10⁹ /L was significantly associated with pediatrics compared to adults. t(8;21)(q22;22) was significantly associated with thrombocytopenia in adults. We conclude that no significant difference is found between KIT mutated and unmutated CBF-AML in adults and pediatrics. Children with CBF-AML present with leukocytosis. t(8;21) is associated with thrombocytopenia.

Improving patient outcomes in fibrous dysplasia/McCune-Albright syndrome: an international multidisciplinary workshop to inform an international partnership

To develop consensus on improving the management of patients, we convened an international workshop involving patients, clinicians, and researchers. Key findings included the diagnostic delay and variability in subsequent management with agreement to develop an international natural history study. We now invite other stakeholders to join the partnership.

PURPOSE

The aim of this study was develop a consensus on how to improve the management of patients with fibrous dysplasia and prioritize areas for research METHODS: An international workshop was held over 3 days involving patients, clinicians, and researchers. Each day had a combination of formal presentations and facilitated discussions that focused on clinical pathways and research.

RESULTS

The patient workshop day highlighted the variability of patients' experience in getting a diagnosis, the knowledge of general clinical staff, and understanding long-term outcomes. The research workshop prioritized collaborations that improved understanding of the contemporary natural history of fibrous dysplasia/McCune-Albright syndrome (FD/MAS). The clinical workshop outlined the key issues around diagnostics, assessment of severity, treatment and monitoring of patients.

CONCLUSIONS

In spite of advances in understanding the genetic and molecular underpinnings of fibrous dysplasia/McCune-Albright syndrome, clinical management remains a challenge. From the workshop, a consensus was reached to create an international, multi-stakeholder partnership to advance research and clinical care in FD/MAS. We invite other stakeholders to join the partnership.

Vitamin D receptor gene polymorphism in Egyptian pediatric acute lymphoblastic leukemia correlation with BMD

INTRODUCTION

We studied the frequencies of the 3' and 5'-end vitamin D receptor (VDR) gene polymorphisms and their correlation with bone mineral density (BMD) in Egyptian pediatric acute lymphoblastic leukemia (ALL) patients receiving calcium and vitamin D supplements. The purpose of this study is to find out the relation between VDR polymorphism and the response to vitamin D intake in pediatric ALL cases who receive corticosteroid therapy which predispose to osteoporosis. This study might shed the light on some genetic variants that are effect the response of individuals to vitamin D therapy.

METHODS

Forty newly diagnosed pediatrics ALL cases were studied. Three SNPs at the 3'-end of the VDR gene (BsmI rs1544410, ApaI rs739837and TaqI rs731236) and two SNPs at the 5'-end (Cdx-2 rs11568820 and GATA rs4516035) were analyzed by Allelic discrimination assay. Of those twenty-six cases with initial BMD data available were further analyzed with regards to the effect of various VDR genotypes/haplotypes on BMD.

RESULTS

The genotype frequencies at 3'-end of VDR gene were, TaqI TT 23%, Tt 54% and tt 23%, BsmI bb 19.2%, Bb 65.4% and BB 15.4% and ApaI AA 12%, Aa 27% and aa 61%. The frequencies at the 5'-end were Cdx-2 GG 34.5%, GA 54% and AA 11.5% and GATA AA 8%, AG 50% and GG 42%. Eight and four possible haplotypes were observed at the 3' and 5'-ends of the VDR gene respectively. The Tt genotype was significantly correlated with high BMD as compared to other TaqI genotypes (P = 0.0420). There was a trend towards higher BMD with the genotype Bb as compared to other BsmI genotypes. No statistical significance was found between the other VDR genotypes or haplotypes studied and BMD.

CONCLUSIONS

This is the first report on VDR gene polymorphisms in Egyptian pediatric ALL patients. The Tt genotype was associated with increased BMD. Our study showed marked genetic heterogeneity in VDR gene in Egyptian pediatric ALL patients.

Abstract B07: Prevalence of the most common fusion gene transcripts in 1080 Egyptian pediatric acute lymphoblastic leukemia patients: Children Cancer Hospital Egypt (CCHE) experience

Introduction: Childhood acute lymphoblastic leukemia (ALL) is a highly heterogeneous disease with distinct biological subgroups.

Objective: To detect the incidence of the most common fusion gene transcripts in a large cohort of de novo Egyptian pediatric precursor B-ALL as well as relapsed cases for the first time in Egypt. To compare our results with other Western and Eastern countries to see if there is ethnic variation.

Procedure: The study included 1080 consecutive patients with de novo precursor B-ALL and 58 relapsed cases with age ≤ 18 years that were admitted and treated at Children Cancer Hospital Egypt (CCHE) from July 2007 till December 2013. Diagnosis was established by morphological examination and immunophenotyping. All cases were subjected to cytogenetic and molecular analysis. RT-PCR was carried out to test for the most common fusion gene transcripts t(12;21) ETV6/RUNX1, t(1;19) TCF3/PBX1, t(9; 22) BCR/ABL and t(4; 11) MLL/AF4.

Results: Out of 1080 newly diagnosed cases, ETV6-RUNX1 was found in 165 (15.3%), E2A-PBX1 in 74 (6.9 %), BCR-ABL in 41 (3.9%) and MLL-AF4 in 20 (1.9 %). The incidence in relapsed cases was 6.7%, 6.7%, 1.7% and 5.1% respectively. As regards immunophenotyping, ETV6-RUNX1 was highly correlated with CALL, E2A-PBX to Pre-B and MLL-AF4 to Pro-B (p 0.0001, 0.0001, 0.0001) while BCR-ABL was not related to any phenotype. As regarding age, all fusion genes were highly correlated to the age group 1-10 years (p 0.0001, 0.007, 0.0001) except MLL-AF4 was correlated to 0-1 age group (p 0.0001). As regards total leucocytic count (TLC), E2A-PBX1 and BCR-ABL were correlated to &lt; 50x103/µl and MLL-AF4 to &gt; 100x103/µl while ETV6-RUNX1 showed no correlation.

ETV6-RUNX1 (15.3%) was much lower than that reported by United States and Western Europe that have range 19-26% with a median of 23% while it is nearly comparable with Far East range of 13.4-17.5%. BCR-ABL (3.9%) is a little bit higher than western 2% while lower than Far East 6.65%. E2A-PBX1 (6.9%) was little higher than Western 3-5% and Far East 4.9%. MLL-AF4 1.9% was comparable with both Western and Far East (2-3%). Comparison with Middle East which is of limited number of studies; ETV6-RUNX1 was higher than Iraq, Kuwait, and Jordan 12.1%, 11.7%, 12% but much lower than Saudi Arabia 21%. E2A-PBX1 was much higher than Kuwait, Iraq and Saudi Arabia (1.8%, 4.2%, and 4.2%). BCR-ABL was comparable.MLL-AF4 was comparable with Saudi Arabia (2.5%) but lower than Kuwait and Iraq (3.6%, 4.2%). About relapsed cases, ETV6-RUNX1, BCR-ABL and MLL-AF4 were much lower than Western Europe and Far East.

Conclusion: These frequency differences of molecular markers in childhood ALL confirm the Ethnic and geographic variation. Other factors may play a role such as exposure to environmental oncogenic factors and of course differences among laboratories may play part in this difference. So we should put into consideration that this frequency difference may have important implication for prognosis, drug selection and treatment outcome.

Citation Format: Dina Yassin, Sonya Soliman, Khaled Shaaban, Sherine Salem, Nayera Hamdy, Hala Reda, Iman Sidhom, Abeer Mokhles, Nesreen Aly, Amr EL Nashar, Wafaa Rashed, Mai Mahmoud, Sarah Hesham, Alaa ELHaddad. Prevalence of the most common fusion gene transcripts in 1080 Egyptian pediatric acute lymphoblastic leukemia patients: Children Cancer Hospital Egypt (CCHE) experience. [abstract]. In: Proceedings of the AACR Special Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; Sep 20-23, 2014; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(17 Suppl):Abstract nr B07.

High-dose methotrexate in Egyptian pediatric acute lymphoblastic leukemia: the impact of ABCG2 C421A genetic polymorphism on plasma levels, what is next?

PURPOSE

High-dose methotrexate (HD-MTX) is a cornerstone antineoplastic drug in most treatment protocols of pediatric acute lymphoblastic leukemia (ALL). Among the membrane efflux transporters of MTX, the human breast cancer resistant protein is the second member of the G subfamily of ATP-binding cassette (ABC) efflux pump (ABCG2). A single-nucleotide polymorphism (SNP) in ABCG2, the exchange of C to A at position 421, represents 13 % in the Middle Eastern population. We studied the effect of this SNP on the plasma levels of HD-MTX in Egyptian pediatric ALL.

METHODS

Two hundred ALL patients were recruited from Children's Cancer Hospital Egypt-57357, and all were treated according to the St Jude Total XV protocol. Determination of plasma MTX levels was done at 23, 42 and 68 h. Genotyping of C421A of ABCG2 was done by polymerase chain reaction-restriction fragment length polymorphism.

RESULTS

We found 14.5 % of the variant allele of the ABCG2 C421A SNP. The statistical association between ABCG2 421C>A SNP and the cutoff toxic plasma level of 24 h HD-MTX infusion at different time points tested was not statistically significant. There was no statistical significance between steady-state plasma concentration in patients with and without with this SNP.

CONCLUSION

To date, this is the largest study on Egyptian ALL patients for this SNP. This study shows that there is no effect of ABCG2 421C>A on plasma concentrations of HD-MTX. Replacing candidate gene association studies with genome-wide studies of HD-MTX is now mandatory and is part of our research blueprint.

Outcome of risk-adapted therapy for pediatric acute lymphoblastic leukemia in Egypt

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Background: With modern risk directed therapy, >80% of children with acute lymphoblastic leukemia (ALL) in western countries are cured. The 5-year event free survival (EFS) and relapse free survival (RFS) of pediatric ALL patients in Egypt were 65% and 75% respectively in a previous study using an intensive treatment protocol for all patients. Aim: To improve cure rates of Egyptian children with ALL using risk adapted therapy. Methods: From July 2007 to December 2010, 706 patients aged 1-18 years with newly diagnosed ALL were treated at Children Cancer Hospital Egypt with a risk directed ALL protocol adopted from St Jude Total Study XV. Results: B-precursor phenotype was encountered in 75.8% and T-cell in 24.2%. Based on initial presentation and response to therapy measured by minimal residual disease (MRD), 42.6%, 45.8% and 11.6% of the patients were classified as low, intermediate and high risk respectively. The 5-year RFS and EFS were 88.2 ± 1.5% and 76.5 ± 1.7% respectively. Adverse events included 4.4% induction deaths, 2.5% failure to achieve induction remission (1.4% remained refractory), 6.8% deaths in remission, 9.2% relapses (3.1% hematological, 1.8% combined hematological and CNS, 4% isolated CNS, 0.3% isolated testicular), 0.9% abandonment of therapy and one patient had secondary myeloid leukemia. The median follow up for patients alive in CR was 43months (range 24–65). The 5-year RFS of the low, intermediate and high risk groups were 92.2 ± 2.4%, 85.3 ± 2.2% and 82.7 ± 4.8% respectively (p=0.001), while the 5-year EFS were 87.6 ± 2.5%, 78.2 ± 2.5% and 57.9 ± 5.7% respectively (p<0.001). Prognostic factors that had statistically significant unfavorable impact on both EFS and RFS by univariate analysis were age ≥10 years, TLC ≥100x109/L, T-cell phenotype, risk groups, MRD d42 ≥1% and MRD W7 ≥0.1%, while MRD d15 ≥1% had statistically significant unfavorable outcome on EFS only. By multivariate analysis, TLC and MRD W7 had prognostic significance on EFS and RFS, MRD d42 on EFS, while MRD d15 had marginal significance on EFS (p=0.055). Conclusions: Risk adapted therapy was effective in improving ALL survival among patients at our institution compared with previous trials, although the outcome remains lower than that in high income countries.

Synthesis and anti-proliferative activity of substituted-anilinoquinazolines and its relation to EGFR inhibition

4-Anilinoquinazoline is a privileged scaffold in developing small molecule inhibitors of tyrosine kinases (TK) especially epidermal growth factor receptor (EGFR). 2 series belonging to 3'-substituted-4-anilinoquinazoline scaffold were synthesized and screened in vitro on isolated and a breast cancer cell line. The research aims at exploring the activity of compounds having diverse substituents at 3' position of the aniline moiety. Generally, the meta-substituted-anilinoquinazolines exhibited significant inhibitory activity against isolated enzyme as well as MCF-7 cancer cell line. For instance, compound 10b inhibited >99% of EGFR activities at 10 µM concentration. 6 of the tested compounds exhibited range of anti-proliferative activity below 10 µM potency. In particular, compounds 6e and 10b displayed the highest activity among the tested compounds with IC50 values equal to 8.6 and 4.84 µM, respectively. Structure-based tools were utilized to rationalize EGFR-TK binding of compound 10b since it is the most active compound in the enzyme inhibition test.

Clinical significance of immunophenotypic markers in pediatric T-cell acute lymphoblastic leukemia

BACKGROUND

Cell-marker profiling has led to conflicting conclusions about its prognostic significance in T-ALL.

AIM

To investigate the prevalence of the expression of CD34, CD10 and myeloid associated antigens (CD13/ CD33) in childhood T-ALL and to relate their presence to initial clinical and biologic features and early response to therapy.

PATIENTS AND METHODS

This study included 67 consecutive patients with newly diagnosed T-ALL recruited from the Children's Cancer Hospital in Egypt during the time period from July 2007 to June 2008. Immunophenotypic markers and minimal residual disease (MRD) were studied by five-color flow cytometry.

RESULTS

The frequency of CD34 was 34.9% , CD10 33.3% , while CD13/CD33 was 18.8%. No significant association was encountered between CD34, CD10 or myeloid antigen positivity and the presenting clinical features as age, sex, TLC and CNS leukemia. Only CD10(+) expression had significant association with initial CNS involvement (p=0.039). CD34 and CD13/CD33 expression was significantly associated with T-cell maturation stages (p<0.05). No relationship was observed for age, TLC, gender, NCI risk or CNS involvement with early response to therapy illustrated by BM as well as MRD day 15 and day 42. CD34(+), CD13/CD33(+) and early T-cell stage had high MRD levels on day 15 that was statistically highly significant (p<0.01), but CD10(+) had statistically significant lower MRD level on day 15 (p=0.049). However, only CD34 retained its significance at an MRD cut-off level of 0.01%.

CONCLUSIONS

CD34, CD10, CD13/CD33 expression, as well as T-cell maturation stages, may have prognostic significance in pediatric T-ALL as they have a significant impact on early clearance of leukemic cells detected by MRD day 15.

Sheep red blood cells armed with anti-CD20 single-chain variable fragments (scFvs) fused to a glycosylphosphatidylinositol (GPI) anchor: a strategy to target CD20-positive tumor cells

Single-chain variable fragment antibodies (scFv) retain antigen specificity and offer advantages over intact antibodies as therapeutic agents. We cloned the cDNA of the V(H) and V(kappa) regions from a mouse hybridoma (HB-9645) directed against human CD20. In addition to the basic scFv construct (V(kappa)-L-V(H)), we genetically engineered a secretory signal, six histidine residues, and a 'Flu' tag to facilitate secretion, purification, and detection. A glycosyl-phosphatidylinositol (GPI) modification signal was added at the C terminus. The GPI-tagged and the non-tagged scFvs were expressed in high yields on the surface of stably transfected insect cells. The CD20-binding properties of purified non-GPI tagged scFv were examined using flow cytometry and immunocytochemistry. The non-GPI-tagged scFv selectively recognizes CD20-positive cells in a concentration-dependent manner. Double-flow cytometry analysis using fresh peripheral blood lymphocytes and WSU-FSCCL cells revealed that our scFv resolves the B-cell population better than the intact antibody. The GPI-tagged scFv was loaded onto the surface of sheep erythrocytes to form rosettes with CD20-positive cells. The genetically engineered anti-CD20 scFv and GPI-tagged derivative have binding specificity for the CD20 antigen. The scFvs described here has potential uses as an in vivo tumor-imaging agent and as a carrier vehicle for targeted delivery of cytocidal agents to CD20-positive cancer cells.

Bcl-2 antisense oligonucleotides are effective against systemic but not central nervous system disease in severe combined immunodeficient mice bearing human t(14;18) follicular lymphoma

The t(14;18) is present in 85-90% of follicular lymphomas. It results in overexpression of the Bcl-2 protein, which inhibits apoptosis and plays a role in lymphomagenesis. Bcl-2 antisense oligonucleotides (ODNs) down-regulate Bcl-2 expression and inhibit growth of the follicular lymphoma cell line WSU-FSCCL. In this study, we have established a human lymphoma xenograft model in severe combined immunodeficient (SCID) mice using the WSU-FSCCL cell line. s.c., i.v., or i.p. injection of WSU-FSCCL cells into SCID mice results in the development of disseminated tumors, with the liver, spleen, bone marrow, and lymph nodes as major sites of disease. Tumors were fatal in 7-14 weeks, depending on cell inoculum and route of administration. Immunohistochemistry, flow cytometry, and cytogenetic analysis confirmed the human B-cell origin of tumor cells in the xenograft. Phosphorothioate ODNs against the translation initiation site of bcl-2 mRNA in the antisense and mismatched antisense sequences were administered i.v. or i.p. to the xenograft models three times a week for 2 weeks, starting on day 7 after tumor injections. Antisense-treated animals had significantly longer survival (mean, 11.6 weeks) compared with 7.6 weeks for the control group and 7.5 weeks for the mismatched antisense-treated animals (P = 0.002 and 0.004, respectively). More significantly, a pathological examination showed no tumor in the liver, spleen, or bone marrow of the antisense group. However, subsequent experiments showed that the central nervous system was involved, causing mice to die although other sites were disease free. We conclude that bcl-2 antisense ODN therapy is effective against systemic FSCCL disease in SCID mice xenografts; however, it does not prevent disease dissemination into the central nervous system causing animal death.

A new tubulin polymerization inhibitor, auristatin PE, induces tumor regression in a human Waldenstrom's macroglobulinemia xenograft model

Waldenstrom's macroglobulinemia (WM) is an uncommon lymphoproliferative disease which remains incurable with current treatment protocols. We have previously established a permanent WM cell line, WSU-WM, which grows as a xenograft in severe combined immune deficient (SCID) mice. In this study, we investigated the anti-tumor effects of auristatin PE (a structural modification of the marine, shell-less mollusk peptide constituent dolastatin 10). WSU-WM cells were cultured in RPMI-1640 at a concentration of 2x10(5) cells/ml using 24-well plates. Auristatin PE or dolastatin 10 were added to triplicate wells and cell count and viability were assessed after 24, 48 and 72 h. Results showed that both agents were active against WSU-WM, and were able to induce complete growth inhibition at 100 pg/ml. The efficacy of these agents in vivo was evaluated using the WSU-WM SCID mouse xenograft model. Auristatin PE and dolastatin 10 were given i.v. via tail vein at 2.0 mg/kg and 0.2 mg/kg, respectively. The agents were given every second day for three injections which represent the maximum tolerated doses. Tumor growth inhibition (T/C), tumor growth delay (T-C), and log10 kill for auristatin PE and dolastatin 10 were 0%, 18 days, 2.83 and 67%, 2 days, 0.06, respectively. Based on these animal results, dolastatin 10 was inactive while auristatin PE was highly active. We therefore focused further investigation on auristatin PE to understand some of its mechanisms of action. Using two flow cytometry assays, propidium iodide for cell cycle analysis and 7-amino actinomycin D (7AAD) to detect apoptosis, we were able to demonstrate that auristatin PE at 10 pg/ml after 24 h arrested 50% of WSU-MW cells in G2M. Concomitantly, 31% of auristatin PE-treated cells entered apoptosis. By 72 h, greater than 75% of the cells became apoptotic. The activity of auristatin PE should be evaluated in other tumor types and in clinical trials.

Treatment of a de novo fludarabine resistant-CLL xenograft model with bryostatin 1 followed by fludarabine

WSU-CLL is a de novo fludarabine resistant cell line established from a patient with advanced chronic lymphocytic leukemia (CLL) refractory to chemotherapy including fludarabine (Flud). Our previous studies indicate that bryostatin 1 (Bryo 1) induces differentiation of WSU-CLL and increases the ratio of dCK/5'-NT activity and Bax/Bcl-2. This study tests the hypothesis that Bryo 1-differentiated cells are more susceptible to Flud than the parent WSU-CLL cells. Flud, given sequentially after Bryo 1, in vitro and in vivo animal studies resulted in significantly higher rates of growth inhibition and improved animal survival. Flud at 100 to 600 nM exhibited a dose-dependent growth inhibitory effect on the WSU-CLL cell line. The sequential exposure to Bryo 1 (10 nM for 72 h) followed by Flud (100 nM) resulted in significantly higher rates of growth inhibition than either the reverse addition of these two agents or each agent alone, but was not significantly different than the concurrent addition of Bryo 1 + Flud. Using 7-amino-actinomycin D staining and flow cytometry, apoptosis was seen in 40.8% of cells treated with Bryo 1 (10 nM, 72 h) followed by Flud, compared with Flud (100 nM, 72 h) followed by Bryo 1 (18.1%). To demonstrate that Bryo 1 enhancement of Flud efficacy was not restricted to in vitro culture, we used the WSU-CLL xenograft model in mice with severe combined immune deficiency (SCID). Bryo 1 + Flud at the maximum tolerated doses (75 microg/kg i.p. and 200 mg/kg i.v., respectively) were administered to mice in different combinations. The survival in days, the tumor growth inhibition ratio (T/C), the tumor growth delay (T-C) in days, log10 kill, as well as mean tumor weight (mtw) of mice treated with Bryo 1 followed by Flud, were significantly better than control and other groups. T/C%, T-C, log10 kill and mtw were as follows: Bryo 1 (36.8%, 10 days, 0.8, 375 mg); Flud (100%, 0. 0 day, 0.0, 1130 mg); Bryo 1 + Flud (14.3%, 12 days, 0.95, 288 mg); Bryo 1 followed by Flud (4.6%, 17 days, 1.35, 35 mg); Flud followed by Bryo (40.3%, 10 days, 0.80, 175 mg). We conclude that: i) Bryo 1 sensitizes WSU-CLL cells to Flud and enhances apoptosis; ii) the sequential treatment with Bryo 1 followed by Flud resulted in higher anti-tumor activity compared with either agent alone, in combination, or the reverse addition of these agents and iii) these results are comparable to those of Bryo 1 followed by 2-CdA suggesting common pathway(s) of interaction between Bryo 1 and purine analogues.

Potentiation of 2-chlorodeoxyadenosine activity by bryostatin 1 in the resistant chronic lymphocytic leukemia cell line (WSU-CLL): association with increased ratios of dCK/5'-NT and Bax/Bcl-2

The activities of 2-chlorodeoxyadenosine (2-CdA) metabolizing enzymes, deoxycytidine kinase (dCK) and cytosolic 5'-nucleotidase (5'-NT) were measured in control and bryostatin 1 treated CLL cells using an EBV-negative WSU-CLL cell line. This cell line was established from a patient with CLL resistant to fludarabine. The results revealed a significant increase in dCK activity in bryostatin 1 treated cells at 48 and 72 h compared with the control. 5'-NT activity decreased significantly at 48 h. The ratio of dCK to 5'-NT activity was significantly increased in bryostatin 1 treated WSU-CLL cells after 48 h. WSU-CLL cells treated with bryostatin 1 exhibited an increase in the percentage of apoptotic and dead cells from control levels of 16% to 40%. This percentage was further increased to 67% following the addition of 11.2 microM 2-CdA to WSU-CLL cells pretreated with bryostatin 1. Results from Western blot analysis indicate that WSU-CLL cells express high levels of Bcl-2, Bcl-xL and c-myc, and a low level of Bax. p53 in untreated WSU-CLL cells is undetectable. WSU-CLL cells treated with bryostatin 1 showed a significant increase in the ratio of Bax to Bcl-2. To demonstrate that the bryostatin 1 mediated enhancement of 2-CdA efficacy was not restricted to in vitro cell culture, we have studied the tumor growth delay of WSU-CLL xenografts treated with placebo, bryostatin 1, 2-CdA, and bryostatin 1 followed by 2-CdA. SCID mice given bryostatin 1 at 75 microg x kg(-1) x d(-1) for 5 days followed by 30 mg x kg(-1) x d(-1) 2-CdA for 5 days in two cycles, had significantly improved tumor growth delay (P = 0.05). We conclude that bryostatin 1 is not only capable of inducing apoptosis by itself, but also sensitizes de novo resistant WSU-CLL cells to the chemo-therapeutic effects of 2-CdA. The bryostatin 1-induced increased ratio of dCK/5'-NT activity and an increased ratio of Bax/Bcl-2 are at least two mechanisms through which this natural compound is able to potentiate the anti-tumor activity of 2-CdA in otherwise resistant CLL cells.

Molecular epidemiology of acute lymphoblastic leukemia in Egypt

We have characterized immunophenotypically defined acute lymphoblastic leukemia (ALL) in Egypt for rearrangements of the antigen receptor genes, and correlated this with rearrangements of ALL-1 and the presence of p53 mutations. Thirty-nine cases were analyzed for rearrangements of the immunoglobulin (Ig) and T-cell receptor (TCR) genes. All precursor B-cell ALLs (12 cases) contained rearranged Ig heavy-chain (JH) region which was biallelic in 92% of these tumors. In addition to JH rearrangements, TCR delta, beta and gamma rearrangements were observed in 80, 40 and 30% of these cases, respectively. TCR genes were invariably rearranged in T-cell ALLs (11 cases). A small fraction (2/11) of T-cell ALL showed concurrent IgJH rearrangement which was monoallelic. Simultaneous rearrangement of IgJH and TCR genes was also observed in both cases of biphenotypic ALL (coexpressing B and T markers). We observed marked heterogeneity in the pattern of rearrangement of antigen receptor genes in mixed-lineage leukemias (ALL coexpressing myeloid-associated markers), including the retention of germline configuration in two cases. Rearrangements of the ALL-1 gene were confined to the leukemias that demonstrated lineage infidelity. Mutations in p53 were infrequent and were present in only three of 47 ALL cases (6%) analyzed; two of these were mixed-lineage leukemias. These results suggest that mixed-lineage and biphenotypic leukemias accumulate pathogenetic lesions that are distinct from B- and T-cell ALL, and that ALL in developing countries includes molecular entities similar to those in developed countries.

Mutations in the coding region of c-myc occur independently of mutations in the regulatory regions and are predominantly associated with myc/Ig translocation

Constitutive expression of c-myc resulting from a chromosomal translocation, which juxtaposes c-myc to an immunoglobulin gene, is a pivotal lesion in Burkitt's lymphomas. This deregulated expression of c-myc is associated with mutations in the regulatory regions, i.e. the first exon and the first intron of c-myc in tumors where the chromosomal breakpoint is not itself within the regulatory region. Until recently it was widely believed that the c-myc protein in these tumors is wild type. We have demonstrated that in a fraction of Burkitt's lymphomas from Africa and from the continental USA, and in mouse plasmacytomas, the c-myc gene carries mutations in the coding region. We now show that, occasionally, such mutations are also present in multiple myelomas--tumors which do not carry translocations or amplifications of c-myc. We also show that the frequency of the c-myc coding region mutations in BL is independent of the frequency of mutations in the regulatory region. These results suggest that the mechanisms that induce missense mutations involving the coding region of c-myc may be different from those that lead to mutations in the regulatory regions.

Mutations in the coding region of c-myc occur frequently in acquired immunodeficiency syndrome-associated lymphomas

We have analyzed 30 cases of high- and intermediate-grade acquired immunodeficiency syndrome-associated non-Hodgkin's lymphoma (AIDS-NHL) for mutations in the c-myc coding region. In addition, in these same tumors, we have sought the presence of mutations in a regulatory region within the first c-myc intron defined by the binding to a factor that inhibits c-myc transcription (MYC intron factor, or mif). Mutations in the c-myc coding region were present in 10 of 16 small noncleaved cell lymphoma (SNCL), but in only 3 of 14 other histologic subtypes tested (0/3 large non-cleaved cell, 2/8 immunoblastic, and 1/3 anaplastic large cell lymphomas). Nineteen of the AIDS-NHLs analyzed contained a c-myc rearrangement and in 10 of these the c-myc gene was mutated in its coding region. In contrast, we could detect a mutation in the coding region in only 2 of 8 AIDS-NHL without a c-myc rearrangement. Mutations in the mif region were detected in 5 of 16 SNCL. Among AIDS-NHL carrying mutations in the c-myc coding region, only 4 carried mutations in the regulatory region. These results suggest that the mutations in the coding region of the c-myc protein may either be a consequence of the translocations involving c-myc, or may be necessary only in tumors where c-myc is deregulated as a result of a c-myc/lg translocation.

Molecular characterization of scl rearrangements in T-cell all from India and egypt

SCL gene rearrangement is the most common molecular lesion (25%) identified so far in T-cell acute lymphoblastic leukemia (T-ALL). Since the frequency of T-ALL appears to be relatively higher in developing countries, we wished to determine as to what fraction of T-ALL from this population harbor SCL rearrangements. We show in this study that although the overall frequency of SCL/SIL rearrangements in T-ALL is similar to the Western countries this is at the expense of increased type A rearrangements. Whether the paucity of type B rearrangements reflects a difference in disease etiology in this part of the world is to be determined.

Hyperparathyroid bone disease in chronic renal failure

Much has been learnt over the past 80 years of the pathogenesis and management of hyperparathyroid bone disease in uraemia. Clinically it has changed from a rare disorder of childhood and adolescence to a common and difficult problem in patients maintained on dialysis programmes. Whereas effective treatments are now available for hyperparathyroid bone disease, these are not curative and there is clearly much more work to be done before a full understanding of its pathogenesis, and the best methods of treatment and prevention, can be reached.

Double-blind controlled trial of prostacyclin in cerebral infarction

Thirty-two patients with acute cerebral infarction received either prostacyclin or placebo intermittently for 65 hours. Pulse and blood pressure were not altered by prostacyclin. After infusion there was no change in infarct volume or cerebral blood flow in either group. After normalisation for starting values, age and site of cerebral infarction there was a greater than 10% improvement in speech in the prostacyclin group, but minimal changes in neurological score or disability status. Age is related to neurological score at 14 days after stroke by decreasing improvement by 6.8% for each additional 10 years. This study has not been able to demonstrate that prostacyclin is effective in the treatment of ischaemic stroke, but due to the sample size the chance of proving this statistically (the power) was small. Similarly any conclusion that prostacyclin is not effective may be wrong because of the Type II error probability being high.