A simplified minimal residual disease polymerase chain reaction method at early treatment points can stratify children with acute lymphoblastic leukemia into good and poor outcome groups

Association of the clinical profile and overall survival of pediatric patients with acute lymphoblastic leukemia

Introduction

The clarification of etiopathology, the improvement of chemotherapy regimens and their risk stratifications, and the improvement in treatment support have increased the survival of children and adolescents affected by Acute Lymphoblastic Leukemia (ALL) past few years. This study aimed to estimate overall survival (OS) and event-free survival (EFS) in an onco-hematology treatment center in Brazil, reports the main clinical-laboratory characteristics of patients at diagnosis, verify the frequency of treatment-related adverse effects and the main causes of death.

Material and methods

Retrospective analysis involving patients diagnosed with ALL, treated with the protocol of the Brazilian Group for Treatment of Leukemias in Childhood (GBTLI), between 2010 and 2020 was carried out; the outcomes (relapse, deaths, development of new neoplasms) were analyzed SPSS® software was used for the statistical analyses, and the p-value was considered significant when less than 0.05 for all analyses.

Results

109 patients were included in the study; the median age was 5 years, with a slight predominance of males. Sixty-six patients were classified as high-risk (HR) group and 43 patients were classified as low-risk (LR) group. After 5 years of diagnosis, the OS was 71.5%, and the EFS was 65%. No statistical difference was found between the HR and LR groups for OS and EFS, while leukocyte counts were statistically associated with the outcome of death (p = 0.028). Among the patients, 28 (25.6%) died due to infection accounting 46.4% of death causes. Among the 34 patients with unfavorable outcomes (death and/or relapse), 32 had no research for the minimal residual disease at the end of remission induction, and 25 were not investigated for the presence of chromosomal abnormalities. The most reported complications and treatment-related adverse effects were increased liver transaminases (85.9%), airway infection (79.4%), oral mucositis (67.2%), febrile neutropenia (64.4%), and diarrhea (36.4%).

Conclusions

The rates of OS and EFS obtained in this cohort are similar to those obtained in the few previous similar studies in Brazil and lower than those carried out in developed countries. The unavailability of prognostic tests may have hindered risk stratification and influenced the results obtained.

Panobinostat (LBH589) increase survival in adult xenografic model of acute lymphoblastic leukemia with t(4;11) but promotes antagonistic effects in combination with MTX and 6MP

Patients diagnosed with acute lymphoblastic leukemia (ALL) bearing t(4;11)/MLL-AF4 have aggressive clinical features, poor prognosis and there is an urgent need for new therapies to improve outcomes. Panobinostat (LBH589) has been identified as a potential therapeutic agent for ALL with t(4;11) and studies suggest that the antineoplastic effects are associated with reduced MLL-AF4 fusion protein and reduced expression of HOX genes. Here, we evaluated the in vitro effects of the combination of LBH589 with methotrexate (MTX) or 6-mercaptopurine (6MP) by cell proliferation assays and Calcusyn software in ALL cell line (RS4;11); the in vivo effects of LBH589 in xenotransplanted NOD-scid IL2Rgamma^null mice measuring human lymphoblasts by flow cytometry; and the expression of HOX genes by qPCR after treatment in an adult model of ALL with t(4;11). LBH589 combination with MTX or 6MP did not promote synergistic effects in RS4;11 cell line. LBH589 treatment leads to increased overall survival and reduction of blasts in xenotransplanted mice but caused no significant changes in HOXA7, HOXA9, HOXA10, and MEIS1 expression. The LBH589, alone, showed promising antineoplastic effects in vivo and may represent a potential agent for chemotherapy in ALL patients with t(4;11).

A Nomogram for the Prediction of Progression and Overall Survival in Childhood Acute Lymphoblastic Leukemia

Background: Advances in treatment and supportive care have significantly improved the overall survival (OS) of pediatric patients with acute lymphoblastic leukemia (ALL). However, there is a large number of these patients who continue to relapse after receiving standard treatment. Accurate identification of patients at high risk of relapse and targeted therapy may significantly improve their prognosis. Therefore, the aim of this study was to identify significant prognostic factors for pediatric ALL and establish a novel nomogram for the prediction of survival.

Methods: The ALL clinical data of Phases I and II of the Therapeutic Applicable Research to Generate Effective Treatments (TARGET) project were merged and randomly divided into training and validation groups. The LASSO regression model was used to select the specific factors related to the OS of the training group and generate prognostic nomograms according to the selected characteristics. The predictive accuracy of the nomogram for OS was verified using the concordance index of the training and validation groups, the area under the receiver operating characteristic curve for prognostic diagnosis, and the calibration curve.

Results: A total of 1,000 children with ALL were included in the TARGET project. Of those, 489 patients had complete follow-up data for further analysis. The data were randomly divided into the training group (n = 345) and the validation group (n = 144). Seven clinical characteristics, namely age at diagnosis, peripheral white blood cells, bone marrow and CNS site of relapse, ETV6/RUNX1 fusion, TCF3/PBX1, and BCR/ABL1 status, were selected to construct the nomogram. The concordance indices of the training and validation groups were 0.809 (95% confidence interval: 0.766–0.852) and 0.826 (95% confidence interval: 0.767–0.885), respectively. The areas under the receiver operating characteristic curve of the 3-year, 5-year, and 10-year OS in the training group were 0.804, 0.848, and 0.885, respectively, while that of the validation group were 0.777, 0.825, and 0.863, respectively. Moreover, the calibration curves demonstrated a favorable consistency between the predicted and actual survival probabilities.

Conclusions: Independent predictors of OS in children with ALL included age at diagnosis, white blood cells, bone marrow site of relapse, CNS site of relapse, ETV6/RUNX1 fusion, TCF3/PBX1, and BCR/ABL1 status. The nomograms developed using these high-risk factors can more simply, accurately, and quantitatively predict the survival of children, and improve treatment and prognosis.

Adipokines in young survivors of childhood acute lymphocytic leukemia revisited: beyond fat mass

PURPOSE

This cross-sectional study evaluated the relationship between adipokines (leptin, adiponectin, visfatin, and resistin) and adiposity indexes regarding sex and cranial radiotherapy exposure among young acute lymphocytic leukemia survivors.

METHODS

A multivariate analysis of covariance (MANCOVA) was used to evaluate the joint effect of sex, cranial radiotherapy, and body mass index (BMI) z-score (model 1) or fat mass index (FMI) (model 2) on adipokines.

RESULTS

This study included 55 survivors of childhood acute lymphocytic leukemia between 15 and 23 years of age from both sexes (56.4% female); 43.6% of the sample had undergone cranial radiotherapy (18-24 Gy). The BMI z-score, the FMI, and sex (P<0.050 for all) influenced at least one adipokine, while cranial radiotherapy exposure was marginal in model 2. Parameter estimates from the MANCOVA's final model showed that the BMI z-score (β=-0.437, P=0.010) and the FMI (β=-0.209, P=0.004) negatively influenced adiponectin, while the FMI positively affected resistin (β=0.142, P=0.020). The relationship between leptin, visfatin, and the adiposity ndexes could not be established. In model 1, females presented with increased adiponectin (β=-1.014, P=0.011) and resistin (β=-1.067, P=0.002) levels; in model 2, female sex positively affected adiponectin (β=-1.515, P=0.001) and marginally influenced resistin (β=-0.707, P=0.054) levels. Cranial radiotherapy negatively determined visfatin levels in both final models (P<0.050).

CONCLUSION

Changes in body fat may be associated with adipose tissue dysfunction and should be carefully evaluated in survivors of acute lymphocytic leukemia, considering both sex and cranial radiotherapy exposure, to treat disorders that may possibly aggravate their risk for early cardiovascular disease.

Drug Resistance Biomarkers and Their Clinical Applications in Childhood Acute Lymphoblastic Leukemia

Biomarkers are biological molecules found in body fluids or tissues, which can be considered as indications of a normal or abnormal process, or of a condition or disease. There are various types of biomarkers based on their application and molecular alterations. Treatment-sensitivity or drug resistance biomarkers include prognostic and predictive molecules with utmost importance in selecting appropriate treatment protocols and improving survival rates. Acute lymphoblastic leukemia (ALL) is the most prevalent hematological malignancy diagnosed in children with nearly 80% cure rate. Despite the favorable survival rates of childhood ALL (chALL), resistance to chemotherapeutic agents and, as a consequence, a dismal prognosis develops in a significant number of patients. Therefore, there are urgent needs to have robust, sensitive, and disease-specific molecular prognostic and predictive biomarkers, which could allow better risk classification and then better clinical results. In this article, we review the currently known drug resistance biomarkers, including somatic or germ line nucleic acids, epigenetic alterations, protein expressions and metabolic variations. Moreover, biomarkers with potential clinical applications are discussed.

Comparison between flow cytometry and standard PCR in the evaluation of MRD in children with acute lymphoblastic leukemia treated with the GBTLI LLA - 2009 protocol

Minimal residual disease (MRD) monitoring is of prognostic importance in childhood acute lymphoblastic leukemia (ALL). The detection of immunoglobulin and T-cell receptor gene rearrangements by real-time quantitative PCR (RT-PCR) is considered the gold standard for this evaluation. However, more accessible methods also show satisfactory performance. This study aimed to compare MRD analysis by four-color flow cytometry (FC) and qualitative standard PCR on days 35 and 78 of chemotherapy and to correlate these data with patients' clinical characteristics. Forty-two children with a recent diagnosis of ALL, admitted to a public hospital in Brazil for treatment in accordance with the Brazilian Childhood Cooperative Group for ALL Treatment (GBTLI LLA-2009), were included. Bone marrow samples collected at diagnosis and on days 35 and 78 of treatment were analyzed for the immunophenotypic characterization of blasts by FC and for the detection of clonal rearrangements by standard PCR. Paired analyses were performed in 61/68 (89.7%) follow-up samples, with a general agreement of 88.5%. Disagreements were resolved by RT-PCR, which evidenced one false-negative and four false-positive results in FC, as well as two false-negative results in PCR. Among the prognostic factors, a significant association was found only between T-cell lineage and MRD by standard PCR. These results show that FC and standard PCR produce similar results in MRD detection of childhood ALL and that both methodologies may be useful in the monitoring of disease treatment, especially in regions with limited financial resources.

T-lymphoid/myeloid mixed phenotype acute leukemia and early T-cell precursor lymphoblastic leukemia similarities with NOTCH1 mutation as a good prognostic factor

Purpose: T-lymphoid/Myeloid Mixed phenotype acute leukemia (T/M-MPAL) is ambiguous leukemia which overlaps with early T-cell precursor lymphoblastic leukemia (ETP-ALL). We have revisited the immunophenotyping profile of T/M-MPAL and ETP-ALL to identify differences and/or similarities, as these entities represent a therapeutic challenge in clinical practice. Patients and methods: A total of 26 ETP-ALL and 10 T/M-MPAL cases were identified among 857 cases of childhood leukemia (T-ALL, n=266 and AML, n=591) before any treatment decisions. The variables analyzed were age strata, sex, clinical features, immunophenotyping, and molecular aberrations. Immunophenotyping was performed in all samples using a panel of cytoplasm and membrane antibodies to identify the lineage and blast differentiation. The mutational status of STIL-TAL1, TLX3, RUNX1, NOTCH1, FBXW7, FLT3, IL7R, RAS, KTM2A, and CDKN2A/B was tested using RT-PCR, FISH, and PCR sequencing methods. The outcomes were assessed in terms of overall survival (OS). Results: The immunophenotypes were similar in ETP-ALL and T/M-MPAL, regarding the cellular expression of CD34, CD117, CD13/CD33, and CD11b, although CD2 and HLA-DR were more frequent in T/M-MPAL (p<0.01). aMPO positivity and myelomonocyte differentiation were definitive in separating both entities. NOTCH1, FLT3-ITD, and N/KRAS mutations as well as TLX3 and KMT2A rearrangements were found in both ETP-ALL and T/M-MPAL. Thirty-one patients received ALL protocol whereas five had AML therapy. The overall 5-year survival rate (pOS) was 56.4% for patients treated using ALL protocols. No differences were observed between T/M-MPAL (pOS of 57%) and ETP-ALL (pOS of 56%) patients. The prognostic value of NOTCH1mut was associated with significantly better OS (pOS 90%) than NOTCH1 wt (pOS 37%) (p=0.017). Conclusion: This research can potentially contribute to NOTCH1 as targeted therapy and prognostic assessment of T-cell mixed phenotype leukemia.

CD44 Expression Profile Varies According to Maturational Subtypes and Molecular Profiles of Pediatric T-Cell Lymphoblastic Leukemia

CD44 is a glycoprotein expressed in leucocytes and a marker of leukemia-initiating cells, being shown to be important in the pathogenesis of T cell acute lymphoblastic leukemia (T-ALL). In this study, we have (i) identified the aberrant antigenic pattern of CD44 and its isoform CD44v6 in T-ALL; (ii) tested the association with different T-cell subtypes and genomic alterations; (iii) identified the impact of CD44 status in T-ALL outcome. Samples from 184 patients (123 T-ALL and 61 AML; <19 years) were analyzed throughout multiparametric flow cytometry. Mutations in N/KRAS, NOTCH1, FBXW7 as well as STIL-TAL1 and TLX3 rearrangements were detected using standard molecular techniques. CD44 expression was characterized in all T-ALL and AML cases. Compared with AML samples in which the median fluorescence intensity (MFI) was 79.1 (1–1272), T-ALL was relatively low, with MFI 43.2 (1.9–1239); CD44v6 expression was rarely found, MFI 1 (0.3-3.7). T-ALL immature subtypes (mCD3/CD1a^neg) had a lower CD44 expression, MFI 57.5 (2.7–866.3), whereas mCD3/TCRγδ^pos cases had higher expressions, MFI 99.9 (16.4–866.3). NOTCH1^mut and STIL-TAL1 were associated with low CD44 expression, whereas N/KRAS^mut and FBXW7^mut cases had intermediate expression. In relation to clinical features, CD44 expression was associated with tumor infiltrations (p = 0.065). However, no association was found with initial treatment responses and overall survival prediction. Our results indicate that CD44 is aberrantly expressed in T-ALL being influenced by different genomic alterations. Unraveling this intricate mechanism is required to place CD44 as a therapeutic target in T-ALL.

Initial Diagnostic Workup of Acute Leukemia: Guideline From the College of American Pathologists and the American Society of Hematology

CONTEXT

- A complete diagnosis of acute leukemia requires knowledge of clinical information combined with morphologic evaluation, immunophenotyping and karyotype analysis, and often, molecular genetic testing. Although many aspects of the workup for acute leukemia are well accepted, few guidelines have addressed the different aspects of the diagnostic evaluation of samples from patients suspected to have acute leukemia.

OBJECTIVE

- To develop a guideline for treating physicians and pathologists involved in the diagnostic and prognostic evaluation of new acute leukemia samples, including acute lymphoblastic leukemia, acute myeloid leukemia, and acute leukemias of ambiguous lineage.

DESIGN

- The College of American Pathologists and the American Society of Hematology convened a panel of experts in hematology and hematopathology to develop recommendations. A systematic evidence review was conducted to address 6 key questions. Recommendations were derived from strength of evidence, feedback received during the public comment period, and expert panel consensus.

RESULTS

- Twenty-seven guideline statements were established, which ranged from recommendations on what clinical and laboratory information should be available as part of the diagnostic and prognostic evaluation of acute leukemia samples to what types of testing should be performed routinely, with recommendations on where such testing should be performed and how the results should be reported.

CONCLUSIONS

- The guideline provides a framework for the multiple steps, including laboratory testing, in the evaluation of acute leukemia samples. Some aspects of the guideline, especially molecular genetic testing in acute leukemia, are rapidly changing with new supportive literature, which will require on-going updates for the guideline to remain relevant.

Visfatin is a positive predictor of bone mineral density in young survivors of acute lymphocytic leukemia

Bone mass acquisition may be compromised in survivors of childhood acute lymphocytic leukemia due to various factors, including adiposity. Fat accumulation can affect bone through the direct effect of adipokines or indirectly through the state of chronic inflammation. The aim of this study was to evaluate the effect of body composition and adipokines on bone mass in survivors of acute lymphocytic leukemia. This was a cross-sectional study of 56 survivors aged between 15 and 24 years, 44.6 % of whom received cranial radiotherapy (18-24 Gy), assessed according to body fat, lean mass, and bone mineral density (dual energy X-ray absorptiometry), computed tomography scan-derived abdominal adipose tissue, and adipokines by a multiple regression analysis. Both lumbar spine L₁-L₄ (trabecular bone) and total body (cortical bone) bone mineral density were positively correlated with visfatin (p < 0.050). Lean mass index was positively correlated, while waist-to-height ratio was negatively correlated with cortical bone (p < 0.010). Low bone mineral density for chronological age was detected in 5.4 % of patients in total body, and 8.9 % at the lumbar spine. In survivors of acute lymphocytic leukemia, visfatin may play an important role in the complex relationship between body composition and bone. At present, visfatin may represent a model for further study of bone metabolism, and could possibly explain the unknown mechanisms linking bone metabolism and cancer.

Key Markers of Minimal Residual Disease in Childhood Acute Lymphoblastic Leukemia

The aim of this study was to identify key markers of minimal residual disease (MRD) in childhood Acute Lymphoblastic Leukemia (ALL). Bone marrow samples were collected at presentation from 139 patients with newly diagnosed B-lineage ALL. On the basis of the expression of CD19, CD10, and CD34 antigens by bone marrow cells, combined with the terminal deoxynucleotide transferase (TdT), CD38, CD45, CD58, CD21, CD66c, CD22, and CD33 expression patterns characterized at diagnosis, leukemia-associated immunophenotypes (LAIPs) were identified. One hundred thirty-nine patients with a median age of 4.3 years were screened with 4-color flow cytometry MRD screening, and 119 of them exhibited 1 or more LAIP suitable for further monitoring, constituting a coverage rate of 85.6%. Only 20 of the 139 (14.4%) had no LAIP identified for follow-up. The most applicable antibody combination was TdT/CD10/CD34/CD19 (87/139, 62.6%), followed by CD38/CD10/CD34/CD19 (85/139, 61.2%) and CD45/CD10/CD34/CD19 (58/139, 41.7%). We have identified a relatively effective MRD panel, combined with TdT, CD38, and CD45 as key markers, that is applicable to the majority of newly diagnosed B-lineage ALL.

Association of germline genetic variants in RFC, IL15 and VDR genes with minimal residual disease in pediatric B-cell precursor ALL

Minimal residual disease (MRD) enables reliable assessment of risk in acute lymphoblastic leukemia (ALL). However, little is known on association between MRD status and germline genetic variation. We examined 159 Caucasian (Slavic) patients with pediatric ALL, treated according to ALL-IC-BFM 2002/2009 protocols, in search for association between 23 germline polymorphisms and MRD status at day 15, day 33 and week 12, with adjustment for MRD-associated clinical covariates. Three variants were significantly associated with MRD: rs1544410 in VDR (MRD-day15); rs1051266 in RFC (MRD-day33, MRD-week12), independently and in an additive effect with rs10519613 in IL15 (MRD-day33). The risk alleles for MRD-positivity were: A allele of VDR (OR = 2.37, 95%CI = 1.07–5.21, P = 0.03, MRD-day15); A of RFC (OR = 1.93, 95%CI = 1.05–3.52, P = 0.03, MRD-day33 and MRD-week12, P < 0.01); A of IL15 (OR = 2.30, 95%CI = 1.02–5.18, P = 0.04, MRD-day33). The risk for MRD-day33-positive status was higher in patients with risk alleles in both RFC and IL15 loci than in patients with risk alleles in one locus or no risk alleles: 2 vs. 1 (OR = 3.94, 95% CI = 1.28–12.11, P = 0.024), 2 vs. 0 (OR = 6.75, 95% CI = 1.61–28.39, P = 0.012). Germline variation in genes related to pharmacokinetics/pharmacodynamics of anti-leukemic drugs and to anti-tumor immunity of the host is associated with MRD status and might help improve risk assessment in ALL.

Oral Mucositis in Pediatric Acute Lymphoblastic Leukemia Patients: Evaluation of Microbiological and Hematological Factors

OBJECTIVE

to investigate the associations of oral microbiota, leucocytes count, neutrophil count, platelet counts and hemoglobin level, and the severity of oral mucositis in pediatric patients with acute lymphoblastic leukemia (ALL) receiving chemotherapy.

MATERIALS AND METHODS

71 prospective patients were included. Analyses of oral microbiota and blood sample were conducted on days 14 (D14) and 56 (D56) of the Brazilian GBTLI-99 treatment protocol. Herpes simplex virus (HSV) identification was performed by PCR followed by DNA sequencing analysis. Bacteria and fungi identification was obtained by standard microbiological culture tests.

RESULTS

103 episodes of mucositis occurred, being 65 at D14 and 38 at D56. Most cases positive for herpes viral DNA sequences were identified as HSV-1. At D14, we found a significant association between the severity of mucositis and presence of HSV-1 (p = 0.0347), Candida spp. (p = 0.0078), and low platelet count (p = 0.0064). At D56, we found a significant association between the severity of mucositis and the presence of HSV-1 (p = 0.0317), previous HSV-1 presence on D14 (p < 0.0001) and neutrophil count (p = 0.0211).

CLINICAL RELEVANCE

the identification of risk factors for mucositis in children and adolescents may contribute to the development of new strategies for prevention and/or treatment, reducing the complications associated with this condition.

CONCLUSIONS

the presence of HSV, platelet count, and Candida spp. presence at D14 of ALL induction treatment is associated with increased severity of mucositis in children and adolescents. At D56 of ALL treatment, mucositis severity was associated with neutrophil count, HSV presence, and previous presence of HSV (at D14).

Current Strategies for the Detection of Minimal Residual Disease in Childhood Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common cancer in children. Current treatment strategies for childhood ALL result in long-term remission for approximately 90% of patients. However, the therapeutic response is worse among those who relapse. Several risk stratification approaches based on clinical and biological aspects have been proposed to intensify treatment in patients with high risk of relapse and reduce toxicity on those with a greater probability of cure.

The detection of residual leukemic cells (minimal residual disease, MRD) is the most important prognostic factor to identify high-risk patients, allowing redefinition of chemotherapy. In the last decades, several standardized research protocols evaluated MRD using immunophenotyping by flow cytometry and/or real-time quantitative polymerase chain reaction at different time points during treatment. Both methods are highly sensitive (10⁻³ a 10⁻⁵), but expensive, complex, and, because of that, require qualified staff and frequently are restricted to reference centers.

The aim of this article was to review technical aspects of immunophenotyping by flow cytometry and real-time quantitative polymerase chain reaction to evaluate MRD in ALL.

Potential roles of microRNA-29a in the molecular pathophysiology of T-cell acute lymphoblastic leukemia

Recent evidence has shown that deregulated expression of members of the microRNA-29 (miR-29) family may play a critical role in human cancer, including hematological malignancies. However, the roles of miR-29 in the molecular pathophysiology of T-cell acute lymphoblastic leukemia (T-ALL) has not been investigated. Here, we show that lower levels of miR-29a were significantly associated with higher blast counts in the bone marrow and with increased disease-free survival in T-ALL patients. Furthermore, miR-29a levels are extremely reduced in T-ALL cells compared to normal T cells. Microarray analysis following introduction of synthetic miR-29a mimics into Jurkat cells revealed the downregulation of several predicted targets (CDK6, PXDN, MCL1, PIK3R1, and CXXC6), including targets with roles in active and passive DNA demethylation (such as DNMT3a, DNMT3b, and members of the TET family and TDG). Restoring miR-29a levels in Jurkat and Molt-4 T-ALL cells led to the demethylation of many genes commonly methylated in T-ALL. Overall, our results suggest that reduced miR-29a levels may contribute to the altered epigenetic status of T-ALL, highlighting its relevance in the physiopathology of this disease.

Comparison between qualitative and real-time polymerase chain reaction to evaluate minimal residual disease in children with acute lymphoblastic leukemia

INTRODUCTION

Minimal residual disease is an important independent prognostic factor that can identify poor responders among patients with acute lymphoblastic leukemia.

OBJECTIVE

The aim of this study was to analyze minimal residual disease using immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements by conventional polymerase chain reaction followed by homo-heteroduplex analysis and to compare this with real-time polymerase chain reaction at the end of the induction period in children with acute lymphoblastic leukemia.

METHODS

Seventy-four patients diagnosed with acute lymphoblastic leukemia were enrolled. Minimal residual disease was evaluated by qualitative polymerase chain reaction in 57 and by both tests in 44. The Kaplan-Meier and multivariate Cox methods and the log-rank test were used for statistical analysis.

RESULTS

Nine patients (15.8%) were positive for minimal residual disease by qualitative polymerase chain reaction and 11 (25%) by real-time polymerase chain reaction considering a cut-off point of 1×10(-3) for precursor B-cell acute lymphoblastic leukemia and 1×10(-2) for T-cell acute lymphoblastic leukemia. Using the qualitative method, the 3.5-year leukemia-free survival was significantly higher in children negative for minimal residual disease compared to those with positive results (84.1%±5.6% versus 41.7%±17.3%, respectively; p-value=0.004). There was no significant association between leukemia-free survival and minimal residual disease by real-time polymerase chain reaction. Minimal residual disease by qualitative polymerase chain reaction was the only variable significantly correlated to leukemia-free survival.

CONCLUSION

Given the difficulties in the implementation of minimal residual disease monitoring by real-time polymerase chain reaction in most treatment centers in Brazil, the qualitative polymerase chain reaction strategy may be a cost-effective alternative.

Subcutaneous adipose tissue plays a beneficial effect on subclinical atherosclerosis in young survivors of acute lymphocytic leukemia

Purpose

The aim of this study was to evaluate the relationship between body composition, metabolic profile, adipokines, and carotid intima-media thickness (cIMT) in young survivors of childhood acute lymphocytic leukemia (ALL).

Patients and methods

This cross-sectional study compared 55 ALL survivors, of chronological age between 15 years and 24 years, assigned into two groups according to the exposure to cranial radiation therapy (CRT; 25 irradiated and 30 nonirradiated) with 24 leukemia-free controls, and assessed body fat mass (dual-energy X-ray absorptiometry), computed tomography scan-derived abdominal adipose tissue, lipid profile, blood pressure (BP), adipokines, and cIMT by a multiple regression analysis.

Results

Treatment with CRT had an effect on all of the variables derived from the computed tomography scan: visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) (P<0.050). In a multiple linear regression model, cIMT positively correlated with exposure to CRT (P=0.029), diastolic BP (P=0.016), and leptin-to-adiponectin ratio (P=0.048), while negatively related to SAT (P=0.007).

Conclusion

In young survivors of childhood ALL, CRT modified the distribution of fat and played a critical role in determining cIMT. Leptin-to-adiponectin ratio, a biomarker of abdominal obesity and metabolic syndrome, and diastolic BP also influenced cIMT, a marker of subclinical atherosclerosis. Nonetheless, adiposity-associated vascular disease might be attenuated by SAT. Changes in body fat must be evaluated in this group of patients in the early course of survivorship in order to avoid premature cardiovascular disease associated with atherosclerosis. Yet, further research as regards the possible protective effect of SAT on vascular disease is warranted.

PLK1 expression and BI 2536 effects in childhood acute lymphoblastic leukemia

BACKGROUND

Polo-like kinase 1 (PLK1) is a conserved kinase that mediates various mitotic events. Compelling data have repeatedly demonstrated its upregulation in different neoplasia, being frequently associated with poor prognosis. However, in childhood acute lymphoblastic leukemia (ALL), no studies have yet been conducted.

PROCEDURE

PLK1 expression and association with biological features were evaluated in 65 consecutively diagnosed childhood ALL samples by quantitative real-time PCR. Moreover, the effects of a specific PLK1 inhibitor, BI 2536, was tested against a panel of nine ALL cell lines at nanomolar concentrations (10, 50, 100 nM).

RESULTS

The mRNA expression of PLK1 showed great variability in pediatric ALL, but no difference was evidenced compared to normal bone marrow. Additionally, no association was found between PLK1 mRNA expression with any clinical or biological features. Alternatively, high mRNA expression of PLK1 was present in ALL cell lines. In vitro treatment with BI 2536 strongly diminished growth, while presenting significant reduction in colony formation capacity and increased apoptosis rates. Moreover, strong G2/M arrest was detected suggesting important impaired proliferation after treatment.

CONCLUSIONS

PLK1 mRNA expression level is not associated with prognosis in childhood ALL; however, considering the great variability observed in the sample and the in vitro experiments presented herein, BI 2536 treatment might serve as a promising therapeutic to enhance the efficacy of conventional treatment modalities in some childhood ALL cases.

Increased expression of miR-221 is associated with shorter overall survival in T-cell acute lymphoid leukemia

Background

CD56 expression has been associated with a poor prognosis in lymphoid neoplasms, including T-cell acute lymphoblastic leukemia (T-ALL). MicroRNAs (miRNAs) play an important role in lymphoid differentiation, and aberrant miRNA expression has been associated with treatment outcome in lymphoid malignancies. Here, we evaluated miRNA expression profiles in normal thymocytes, mature T-cells, and T-ALL samples with and without CD56 expression and correlated microRNA expression with treatment outcome.

Methods

The gene expression profile of 164 miRNAs were compared for T-ALL/CD56⁺ (n=12) and T-ALL/CD56^- (n=36) patients by Real-Time Quantitative PCR. Based on this analysis, we decided to evaluate miR-221 and miR-374 expression in individual leukemic and normal samples.

Results

miR-221 and miR-374 were expressed at significantly higher levels in T-ALL/CD56⁺ than in T-ALL/CD56^- cells and in leukemic blasts compared with normal thymocytes and peripheral blood (PB) T-cells. Age at diagnosis (15 or less vs grater than 15 years; HR: 2.19, 95% CI: 0.98-4.85; P=0.05), miR-221 expression level (median value as cut off in leukemic samples; HR: 3.17, 95% CI: 1.45-6.92; P=0.004), and the expression of CD56 (CD56^-vs CD56⁺; HR: 2.99, 95% CI: 1.37-6.51; P=0.006) were predictive factors for shorter overall survival; whereas, only CD56 expression (HR: 2.73, 95% CI: 1.03-7.18; P=0.041) was associated with a shorter disease-free survival rate.

Conclusions

miR-221 is highly expressed in T-ALL and its expression level may be associated with a poorer prognosis.

Cranial radiotherapy predisposes to abdominal adiposity in survivors of childhood acute lymphocytic leukemia

Background

Advances in treatment of acute lymphocytic leukemia increased the likelihood of developing late treatment-associated effects, such as abdominal adiposity, increasing the risk of cardiovascular disease in this population. Cranial radiotherapy is one of the factors that might be involved in this process. The aim of this study was to determine the effect of cranial radiotherapy on adiposity indexes in survivors of acute lymphocytic leukemia.

Methods

A comparative cross-sectional study of 56 acute lymphocytic leukemia survivors, chronological age between 15 and 24 years, assigned into two groups according to the exposure to cranial radiotherapy (25 irradiated and 31 non-irradiated), assessed according to body fat (dual energy X-ray absorptiometry), computed tomography scan-derived abdominal adipose tissue, lipid profile, and insulin resistance.

Results

Cranial radiotherapy increased body fat and abdominal adipose tissue and altered lipid panel. Yet, lipids showed no clinical relevance so far. There were significantly more obese patients among those who received cranial radiotherapy (52% irradiated versus 22.6% non-irradiated), based on dual energy X-ray absorptiometry body fat measurements. Nonetheless, no association was observed between cranial radiotherapy and body mass index, waist circumference, waist-to-height ratio or insulin resistance.

Conclusions

Adolescent and young adult survivors of childhood acute lymphocytic leukemia showed an increase in body fat and an alteration of fat distribution, which were related to cranial radiotherapy. Fat compartment modifications possibly indicate a disease of adipose tissue, and cranial radiotherapy imports in this process.

Gene expression pattern contributing to prognostic factors in childhood acute lymphoblastic leukemia

The present study evaluated the expression profile of 19 genes previously reported in microarray studies and associated with resistance or sensitivity to vincristine (RPLP2, CD44, TCFL5, KCNN1, TRIM24), prednisolone (F8A, CDK2AP1, BLVRB, CD69), daunorubicin (MAP3K12, SHOC2, PCDH9, EGR1, KCNN4) and l-asparaginase (GPR56, MAN1A1, CLEC11A, IGFBP7, GATA3). We studied 140 bone marrow samples at diagnosis from children with acute lymphoblastic leukemia (ALL) treated according to the Brazilian Childhood Leukemia Treatment Group (GBTLI) ALL-99 protocol. The expression profiles of the genes listed above were analyzed by real-time quantitative polymerase chain reaction (PCR) and then related to the clinical and biological prognostic factors. The results showed significant associations (p ≤ 0.05) between the expression levels of genes GPR56, BLVRB, IGFBP7 and white blood cell (WBC) count at diagnosis; GATA3, MAN1A1, CD44, MAP3K12, CLEC11A, SHOC2 and CD10 B-lineage ALL; TCFL5 and bone marrow status at day 14; MAP3K12 and TRIM24 and bone marrow status at day 28; and CD69, TCFL5 and TRIM24 genes and ETV6/RUNX1 positive ALL. The up-regulation of SHOC2 was also associated with better 5-year event-free survival (EFS) in univariate and multivariate analysis (p = 0.02 and p = 0.03, respectively). These findings highlight genes that could be associated with clinical and biological prognostic factors in childhood ALL, suggesting that these genes may characterize and play a role in the treatment outcome of some ALL subsets.

Monoclonal B-cell lymphocytosis (MBL, CD4+/CD8 weak T-cell large granular lymphocytic leukemia (T-LGL leukemia) and monoclonal gammopathy of unknown significance (MGUS): molecular and flow cytometry characterization of three concomitant hematological disorders

The diagnosis of T-cell large granular lymphocytic leukemia in association with other B-cell disorders is uncommon but not unknown. However, the concomitant presence of three hematological diseases is extraordinarily rare. We report an 88-year-old male patient with three simultaneous clonal disorders, that is, CD4+/CD8(weak) T-cell large granular lymphocytic leukemia, monoclonal gammopathy of unknown significance and monoclonal B-cell lymphocytosis. The patient has only minimal complaints and has no anemia, neutropenia or thrombocytopenia. Lymphadenopathy and hepatosplenomegaly were not present. The three disorders were characterized by flow cytometry analysis, and the clonality of the T-cell large granular lymphocytic leukemia was confirmed by polymerase chain reaction. Interestingly, the patient has different B-cell clones, given that plasma cells of monoclonal gammopathy of unknown significance exhibited a kappa light-chain restriction population and, on the other hand, B-lymphocytes of monoclonal B-cell lymphocytosis exhibited a lambda light-chain restriction population. This finding does not support the antigen-driven hypothesis for the development of multi-compartment diseases, but suggests that T-cell large granular lymphocytic expansion might represent a direct antitumor immunological response to both B-cell and plasma-cell aberrant populations, as part of the immune surveillance against malignant neoplasms.

Isolated relapse in the oral cavity of a child with t-lineage acute lymphoblastic leukemia

Despite high cure rates, approximately 20% of patients with acute lymphoblastic leukemia (ALL) have disease relapse. Isolated recurrence in oral cavity is extremely unusual. The aim of this paper is to report a case of an isolated relapse occurred in a child with T-lineage ALL. Clinical picture included swelling and pain in the right upper gingiva of the oral cavity, with no other clinical or hematological alterations. Diagnosis was confirmed by biopsy and immunohistochemical staining. Bone marrow aspiration was normal. Five months later leukemic infiltration of the bone marrow was detected and systemic chemotherapy was reintroduced. This case report highlights the relevance of dental care during and after chemotherapy, not only to treat lesions in the oral cavity resulting from the disease itself or from treatment side effects, but also to detect unusual sites of ALL relapse.

Differential miRNA expression in childhood acute lymphoblastic leukemia and association with clinical and biological features

The present study aimed to analyze the expression profile of the microRNAs previously described as associated with childhood ALL, miR-92a, miR-100, miR-125a-5p, miR-128a, miR-181b, miR-196b and let-7e, and their association with biological/prognostic features in 128 consecutive samples of childhood acute lymphoblastic leukemia (ALL) by quantitative real-time PCR. A significant association was observed between higher expression levels of miR-196b and T-ALL, miR-100 and patients with low white blood cell count at diagnosis and t(12;21) positive ALL. These findings suggest a potential activity of these microRNAs in pediatric ALL biology.

IGFBP7 participates in the reciprocal interaction between acute lymphoblastic leukemia and BM stromal cells and in leukemia resistance to asparaginase

The interaction of acute lymphoblastic leukemia (ALL) blasts with bone marrow (BM) stromal cells (BMSCs) has a positive impact on ALL resistance to chemotherapy. We investigated the modulation of a series of putative asparaginase-resistance/sensitivity genes in B-precursor ALL cells upon coculture with BMSCs. Coculture with stromal cells resulted in increased insulin-like growth factor (IGF)-binding protein 7 (IGFBP7) expression by ALL cells. Assays with IGFBP7 knockdown ALL and stromal cell lines, or with addition of recombinant rIGFBP7 (rIGFBP7) to the culture medium, showed that IGFBP7 acts as a positive regulator of ALL and stromal cells growth, and significantly enhances in-vitro resistance of ALL to asparaginase. In these assays, IGFBP7 function occurred mainly in an insulin- and stromal-dependent manner. ALL cells were found to contribute substantially to extracellular IGFBP7 levels in the conditioned coculture medium. Diagnostic BM plasma from children with ALL had higher levels of IGFBP7 than controls. IGFBP7, in an insulin/IGF-dependent manner, enhanced asparagine synthetase expression and asparagine secretion by BMSCs, thus providing a stromal-dependent mechanism by which IGFBP7 protects ALL cells against asparaginase in this coculture system. Importantly, higher IGFBP7 mRNA levels were associated with lower leukemia-free survival (Cox regression model, P=0.003) in precursor B-cell Ph(-) ALL patients (n=147) treated with a contemporary polychemotherapy protocol.

Prospective evaluation of HSV, Candida spp., and oral bacteria on the severity of oral mucositis in pediatric acute lymphoblastic leukemia

BACKGROUND

Oral mucositis is a common collateral effect among the secondary complications resulting from chemotherapy. The objective of this study was to prospectively evaluate the association of HSV-1, Candida spp., and oral bacteria on the severity of oral mucositis in pediatric acute lymphoblastic leukemia (ALL).

PROCEDURE

Seventy-one prospective patients were included. Analyses of oral microbiota were conducted on days 14 (D14) and 56 (D56) of the Brazilian GBTLI-99 treatment protocol. Herpes simplex virus (HSV) identification was performed by PCR followed by DNA sequencing analysis. Bacteria and fungi identification was obtained by standard microbiological culture tests.

RESULTS

HSV-1 was found in 10.37% of individual patient samples. One sample was positive for HSV-4. On D14, we found an association between the severity of mucositis and the presence of HSV (p = 0.0347) and Candida spp. (p = 0.0078). At D56, we found an association between the severity of mucositis and the presence of HSV on D14 (p < 0.0001) and HSV presence (p = 0.0317).

CONCLUSION

The presence of HSV, mainly HSV-1, and Candida spp. was associated with mucositis severity in pediatric ALL. No association could be found between bacterial CFU and severity of mucositis.

Detection of clonal immunoglobulin and T-cell receptor gene rearrangements in childhood acute lymphoblastic leukemia using a low-cost PCR strategy

BACKGROUND

Immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements function as specific markers for minimal residual disease (MRD), which is one of the best predictors of outcome in childhood acute lymphoblastic leukemia (ALL). We recently reported on the prognostic value of MRD during the induction of remission through a simplified PCR method. Here, we report on gene rearrangement frequencies and offer guidelines for the application of the technique.

PROCEDURE

Two hundred thirty-three children had DNA extracted from bone marrow. Ig and TCR gene rearrangements were amplified using consensus primers and conventional PCR. PCR products were submitted to homo/heteroduplex analysis. A computer program was designed to define combinations of targets for clonal detection using a minimum set of primers and reactions.

RESULTS

At least one clonal marker could be detected in 98% of the patients, and two markers in approximately 80%. The most commonly rearranged genes in precursor B-cell ALL were IgH (75%), TCRD (59%), IgK (55%), and TCRG (54%). The most commonly rearranged genes for T-ALL were TCRG (100%) and TCRD (24%). The sensitivity of primers was limited to the detection of 1 leukemic cell among 100 normal cells.

CONCLUSIONS

We propose that eight PCR reactions per ALL subtype would allow for the detection of two markers in most cases. In addition, these reactions are suitable for MRD monitoring, especially when aiming the selection of patients with high MRD levels (≥ 10(-2)) at the end of induction therapy. Such an approach would be very useful in centers with limited financial resources.

Prognostic significance of minimal residual disease detected by a simplified flow cytometric assay during remission induction chemotherapy in children with acute lymphoblastic leukemia

Purpose

Our study attempted to determine the prognostic significance of minimal residual disease (MRD) detected by a simplified flow cytometric assay during induction chemotherapy in children with B-cell acute lymphoblastic leukemia (B-ALL).

Methods

A total of 98 patients were newly diagnosed with precursor B-ALL from June 2004 to December 2008 at the Asan Medical Center (Seoul, Korea). Of those, 37 were eligible for flow cytometric MRD study analysis on day 14 of their induction treatment. The flow cytometric MRD assay was based on the expression intensity of CD19/CD10/CD34 or aberrant expression of myeloid antigens by bone marrow nucleated cells.

Results

Thirty-five patients (94.6%) had CD19-positive leukemic cells that also expressed CD10 and/or CD34, and 18 (48.6%) had leukemic cells with aberrant expression of myeloid antigens. Seven patients with ≥1% leukemic cells on day 14 had a significantly lower relapse-free survival (RFS) compared to the 30 patients with lower levels (42.9% [18.7%] vs. 92.0% [5.4%], P=0.004). Stratification into 3 MRD groups (≥1%, 0.1-1%, and <0.1%) also showed a statistically significant difference in RFS (42.9% [18.7%] vs. 86.9% [8.7%] vs. 100%, P=0.013). However, the MRD status had no significant influence on overall survival. Multivariate analysis demonstrated that the MRD level on day 14 was an independent prognostic factor with borderline significance.

Conclusion

An MRD assay using simplified flow cytometry during induction chemotherapy may help to identify patients with B-ALL who have an excellent outcome and patients who are at higher risk for relapse.

Low mRNA expression of the apoptosis-related genes CASP3, CASP8, and FAS is associated with low induction treatment response in childhood acute lymphoblastic leukemia (ALL)

BACKGROUND

Defects in apoptosis signaling have been considered to be responsible for treatment failure in many types of cancer, although with controversial results. The objective of the present study was to assess the expression profile of key apoptosis-related genes in terms of clinical and biological variables and of the survival of children with acute lymphoblastic leukemia (ALL).

PROCEDURE

The levels of mRNA expression of the apoptosis-related genes CASP3, CASP8, CASP9, FAS, and BCL2 were analyzed by quantitative real-time PCR in consecutive samples from 139 consecutive children with ALL at diagnosis treated by the Brazilian protocol (GBTLI-ALL 99). Gene expression levels and clinical and biological features were compared by the Mann-Whitney test. Event-free survival (EFS) was calculated by Kaplan-Meier plots and log-rank test.

RESULTS

A significant correlation was detected between CASP3, CASP8, CASP9, and FAS expression levels (P < 0.01) in ALL samples. Higher levels of BCL2 were significantly associated with white blood cell (WBC) count <50,000/mm(3) at diagnosis (P = 0.01) and low risk group classification (P = 0.008). Lower expression levels of CASP3, CASP8 and FAS gene were associated with a poor response at day 7 according the GBTLI-ALL 99 protocol (P = 0.03, P = 0.02 and P = 0.008, respectively). There was a relationship between FAS gene expression lower than the 75th percentile and lower 5-year EFS (P = 0.02).

CONCLUSION

These findings suggest an association between lower expression levels of the pro-apoptotic genes and a poor response to induction therapy at day 7 and prognosis in childhood ALL.

Vascular endothelial growth factor (VEGF) and endothelial nitric oxide synthase (NOS3) polymorphisms are associated with high relapse risk in childhood acute lymphoblastic leukemia (ALL)

BACKGROUND

Angiogenesis has been shown as an important process in hematological malignancies. It consists in endothelial proliferation, migration, and tube formation following pro-angiogenic factors releasing, specially the vascular endothelial growth factor (VEGF), which angiogenic effect seems to be dependent on nitric oxide (NO). We examined the association among functional polymorphisms in these two angiogenesis related genes: VEGF (-2578C>A, -1154G>A, and -634G>C) and NOS3 (-786T>C, intron 4 b>a, and Glu298Asp) with prognosis of childhood acute lymphoblastic leukemia (ALL).

METHODS

The genotypes were determined and haplotypes estimated in 105 ALL patients that were divided in 2 groups: high risk (HR) and low risk of relapse (LR) patients. In addition, event-free survival curves according to genotypes were assessed.

RESULTS

The group HR compared to the LR showed a higher frequency of the alleles -2578C and -634C and the haplotype CGC for VEGF (0.72 vs. 0.51, p<0.008; 0.47 vs. 0.26, p<0.008; and 42.1 vs. 14.5, p<0.006; respectively) and a lower frequency of the haplotype CbGlu (0.4 vs. 8.8,p<0.006), for NOS3.

CONCLUSION

Polymorphisms of VEGF and NOS3 genes are associated with high risk of relapse, therefore may have a prognostic impact in childhood ALL.

mRNA expression profile of multidrug resistance genes in childhood acute lymphoblastic leukemia. Low expression levels associated with a higher risk of toxic death

BACKGROUND

Increased activity of multidrug resistance (MDR) genes has been associated with treatment failure in acute leukemias, although with controversial reports. The objective of the present study was to assess the expression profile of the genes related to MDR: ABCB1, ABCC1, ABCC3, ABCG2, and LRP/MVP in terms of the clinical and biological variable and the survival of children with acute lymphoblastic leukemia (ALL).

PROCEDURE

The levels of mRNA expression of the drug resistance genes ABCB1, ABCC1, ABCC3, ABCG2, and LRP/MVP were analyzed by quantitative real-time PCR using the median values as cut-off points, in consecutive samples from 140 children with ALL at diagnosis.

RESULTS

Expression levels of the ABCG2 gene in the patient group as a whole (P = 0.05) and of the ABCG2 and ABCC1 genes in patients classified as being at high risk were associated with higher rates of 5-year event-free survival (EFS) (P = 0.04 and P = 0.01). Expression levels of the ABCG2 gene below the median were associated with a greater chance of death related to treatment toxicity for the patient group as a whole (P = 0.009) and expression levels below the median of the ABCG2 and ABCC1 genes were associated with a greater chance of death due to treatment toxicity for the high-risk group (P = 0.02 and P = 0.03, respectively).

CONCLUSION

The present data suggest a low participation of the drug efflux genes in treatment failure in patients with childhood ALL. However, the low expression of some of these genes may be associated with a higher death risk related to treatment toxicity.