Monitoring treatment response of childhood precursor B-cell acute lymphoblastic leukemia in the AIEOP-BFM-ALL 2000 protocol with multiparameter flow cytometry: predictive impact of early blast reduction on the remission status after induction

Asparagine transport through SLC1A5/ASCT2 and SLC38A5/SNAT5 is essential for BCP-ALL cell survival and a potential therapeutic target

B-cell precursor acute lymphoblastic leukaemia (BCP-ALL) blasts strictly depend on the transport of extra-cellular asparagine (Asn), yielding a rationale for L-asparaginase (ASNase) therapy. However, the carriers used by ALL blasts for Asn transport have not been identified yet. Exploiting RS4;11 cells as BCP-ALL model, we have found that cell Asn is lowered by either silencing or inhibition of the transporters ASCT2 or SNAT5. The inhibitors V-9302 (for ASCT2) and GluγHA (for SNAT5) markedly lower cell proliferation and, when used together, suppress mTOR activity, induce autophagy and cause a severe nutritional stress, leading to a proliferative arrest and a massive cell death in both the ASNase-sensitive RS4;11 cells and the relatively ASNase-insensitive NALM-6 cells. The cytotoxic effect is not prevented by coculturing leukaemic cells with primary mesenchymal stromal cells. Leukaemic blasts of paediatric ALL patients express ASCT2 and SNAT5 at diagnosis and undergo marked cytotoxicity when exposed to the inhibitors. ASCT2 expression is positively correlated with the minimal residual disease at the end of the induction therapy. In conclusion, ASCT2 and SNAT5 are the carriers exploited by ALL cells to transport Asn, and ASCT2 expression is associated with a lower therapeutic response. ASCT2 may thus represent a novel therapeutic target in BCP-ALL.

Real-World Presentation and Prognostic Effect of Allogeneic Blood Transfusion during the Intensive Induction Phase in Pediatric Acute Lymphoblastic Leukemia

Purpose: To determine associations between allogeneic blood transfusion (ABT) during the intensive induction phase of therapy and prognostic effect in a real-world cohort of pediatric patients with acute lymphoblastic leukemia (ALL). Methods: A total of 749 pediatric patients who were diagnosed with ALL were enrolled in this study by using a single-center retrospective cohort study method from February 2008 to May 2022. Results: Among the ABT patients, 711 (94.9%) children were transfused with packed red blood cells (PRBCs), 434 (57.9%) with single-donor platelets (SDPs), and 196 (26.2%) with fresh frozen plasma (FFP). Our multivariate analysis demonstrated that FFP transfusion was the unique independent factor that affected both relapse-free survival (RFS) and overall survival (OS). The transfusion of FFP was significantly associated with higher age (p < 0.001), being more likely to receive SCCLG-ALL-2016 protocol (p < 0.001), higher proportion of more than 25 blood product transfusions, more PRBC transfusion (p < 0.001), and higher D33-MRD-positive rates (p = 0.013). Generalized additive models and threshold effect analysis using piece-wise linear regression were applied to identify the cut-off value of 25 mL/kg for average FFP transfusion. K-M survival analysis further confirmed that average FFP transfusion > 25 mL/kg was an independent adverse indicator of inferior outcome in terms of RFS (p = 0.027) and OS (p = 0.033). Conclusions: In blood products, only FFP supplement is closely related to the prognosis of childhood ALL. During the intensive induction phase, the indications of FFP transfusion should be strictly grasped, and the total amount of FFP should be controlled and kept below 25 mL/kg.

Childhood Acute Lymphoblastic Leukemia: Results of the Randomized Acute Lymphoblastic Leukemia Intercontinental-Berlin-Frankfurt-Münster 2009 Trial

PURPOSE

The International Berlin-Frankfurt-Münster (BFM) study group conducted a study on pediatric acute lymphoblastic leukemia (ALL). Minimal residual disease (MRD) was assessed using flow cytometry (FCM), and the impact of early intensification and methotrexate (MTX) dose on survival was evaluated.

PATIENTS AND METHODS

We included 6,187 patients younger than 19 years. MRD by FCM refined the risk group definition previously used in the ALL intercontinental-BFM 2002 study on the basis of age, WBC count, unfavorable genetic aberrations, and treatment response measured morphologically. Patients at intermediate risk (IR) and high risk (HR) were randomly assigned to protocol augmented protocol I phase B (IB) versus IB regimen. MTX doses of 2 versus 5 g/m² every 2 weeks, four times, were evaluated in precursor B-cell-ALL (pcB-ALL) IR.

RESULTS

The 5-year event-free survival (EFS ± SE) and overall survival (OS ± SE) rates were 75.2% ± 0.6% and 82.6% ± 0.5%, respectively. Their values in risk groups were standard risk (n = 624), 90.7% ± 1.4% and 94.7% ± 1.1%; IR (n = 4,111), 77.9% ± 0.7% and 85.7% ± 0.6%; and HR (n = 1,452), 60.8% ± 1.5% and 68.4% ± 1.4%, respectively. MRD by FCM was available in 82.6% of cases. The 5-year EFS rates in patients randomly assigned to protocol IB (n = 1,669) and augmented IB (n = 1,620) were 73.6% ± 1.2% and 72.8% ± 1.2%, respectively (P = .55), while those in patients receiving MTX doses of 2 g/m² (n = 1,056) and MTX 5 g/m² (n = 1,027) were 78.8% ± 1.4% and 78.9% ± 1.4%, respectively (P = .84).

CONCLUSION

The MRDs were successfully assessed using FCM. An MTX dose of 2 g/m² was effective in preventing relapse in non-HR pcB-ALL. Augmented IB showed no advantages over the standard IB.

Clinical applicability of short form of Bruininks-Oseretsky Test of Motor Proficiency Second Edition in patients after treatment of acute lymphoblastic leukemia

Introduction

Acute lymphoblastic leukaemia (ALL) ranks among paediatrics' most common oncological malignancies. Monitoring motor performance levels associated with self-sufficiency in the everyday activities of ALL patients is extremely important during treatment. The motor development of children and adolescents with ALL is most often assessed using the Bruininks-Oseretsky Test of Motor Proficiency Second Edition (BOT-2) complete form (CF) with 53 items or the short form (SF) with 14 items. However, there is no evidence in research that BOT-2 CF and SF give comparable results in the population of patients with ALL.

Objective

This study aimed to determine the compatibility of motor proficiency levels achieved from BOT-2 SF and BOT-2 CF in ALL survivors.

Materials and Method

The research sample consists of n = 37 participants (18 girls, 19 boys) aged 4-21 years (10.26, ± SD 3.9) after treatment for ALL. All participants passed BOT-2 CF and were at least 6 months and a maximum of 6 years from the last dose of vincristine (VCR). We used ANOVA with repeated measures, considering the sex, intra-class correlation (ICC) for uniformity between BOT-2 SF and BOT-2 CF scores and Receiving Operating Characteristic.

Results

BOT-2 SF and BOT-2 CF assess the same underlying construct, and BOT-2 SF and CF standard scores have good uniformity: ICC = 0.78 for boys and ICC = 0.76 for girls. However, results from ANOVA showed that the participants achieved a significantly lower standard score in SF (45.1 ± 7.9) compared to CF (49.1 ± 9.4) (p < 0.001; Hays ω ² = 0.41). ALL patients performed the worst in Strength and Agility. According to the ROC analysis, BOT-2 SF obtains acceptable sensitivity (72.3%) and high specificity (91.9%) with high accuracy of 86.1%, and the fair value of the Area Under the Curve (AUC) = 0.734 CI95% (0.47-0.88) in comparison to BOT-2 CF.

Conclusions

To reduce the burden on ALL patients and their families, we recommend using BOT-2 SF instead of BOT-2 CF as a useful screening tool. BOT-SF can replicate motor proficiency with as high probability as BOT-2 CF but systematically underestimates motor proficiency.

Go with the Flow—Early Assessment of Measurable Residual Disease in Children with Acute Lymphoblastic Leukemia Treated According to ALL IC-BFM2009

Simple Summary

Monitoring of residual disease is a very important aspect of modern treatment approaches in many types of cancer. In acute leukemias in both children and adults, molecular and cytometric methods are used to assess the burden of leukemia at different points during therapy. Residual disease measured at the end of induction was shown to be the strongest predictor of outcome. Analyzing the outcomes of children with acute lymphoblastic leukemia (ALL), we aimed to establish the most informative cut-off and time point of assessment. Applying only the measurement of residual disease by flow cytometry along with genotypic findings, we managed to identify patients with a poor prognosis. Although new precise, molecular techniques as the next generation sequencing strategy are approaching daily clinical practice, flow cytometry is still a reliable, standardized method of residual disease detection. We may say ‘go with the flow’; thus, the assessment of residual disease by multiparametric flow cytometry is a proper method for the management of ALL patients according to risk-adapted therapies.

Abstract

Measurable residual disease (MRD) is a well-known tool for the evaluation of the early response to treatment in patients with acute lymphoblastic leukemia (ALL). In respect to predicting the relapse the most informative cut-off and time point of MRD measurement during therapy were evaluated in our study. Between 1 January 2013 and 31 December 2019, multiparametric flow cytometry (MFC) MRD was measured in the bone marrow of 140 children with ALL treated according to the ALL IC-BFM2009 protocol. The MRD cut-off of 0.1% and day 33, end of induction, were the most discriminatory for all patients. Patients with negative MRD on day 15 and 33 had a higher 5-year overall survival—OS (100%) and a higher relapse-free survival—RFS rate (97.6%) than those with positive levels of MRD (≥0.01%) at both time points (77.8% and 55.6%, p = 0.002 and 0.001, respectively). Most patients with residual disease below 0.1% on day 15 exhibit hyperdiploidy or ETV6-RUNX1 in ALL cells. Measurement of MRD at early time points can be used with simplified genetic analysis to better identify low and high-risk patients, allowing personalized therapies and further improvement in outcomes in pediatric ALL.

Cranial MRI in Childhood Acute Leukemia during Treatment and Follow-Up Including the Impact of Intrathecal MTX-A Single-Center Study and Review of the Literature

Due to high survival rates, long-term sequelae, especially neurotoxicity, need to be considered in childhood acute leukemias. In this retrospective analysis of morphologic changes of the brain in children treated for acute leukemias, we included 94 patients (77 ALL, 17 AML; 51 male, 43 female; median age: 5 years) from a single center. We analyzed 170 cranial MRI scans (T2, FLAIR axial) for morphologic alterations of the brain and variations of the ventricular width (GDAH). In addition, the corresponding literature was reviewed. More than 50% of all patients showed cerebral pathomorphologies (CP). They were seen more often in children with ALL (55.8%), ≤ 6 years of age (60.8%), in relapse (58.8%) or after CNS irradiation (75.0%) and included white matter changes, brain atrophy, sinus vein thrombosis and ischemic events. GDAH significantly enlarged mainly in children up to 6 years, with relapse, high-risk leukemias or ALL patients. However, GDAH can normalize again. The number of intrathecal Methotrexate applications (≤12 vs. >12) showed no correlation to morphologic alterations besides a significant increase in GDAH (−0.3 vs. 0.9 mm) between the first and last follow-up MRI in ALL patients receiving >12 ith. MTX applications. The role of ith. MTX on CP needs to be further investigated and correlated to the neurocognitive outcome of children with acute leukemias.

Clinical significance of novel subtypes of acute lymphoblastic leukemia in the context of minimal residual disease-directed therapy

We evaluate clinical significance of recently identified subtypes of acute lymphoblastic leukemia (ALL) in 598 children treated with minimal residual disease (MRD)-directed therapy. Among the 16 B-ALL and 8 T-ALL subtypes identified by next generation sequencing, ETV6-RUNX1, high-hyperdiploid and DUX4-rearranged B-ALL had the best five-year event-free survival rates (95% to 98.4%); TCF3-PBX1, PAX5alt, T-cell, ETP, iAMP21, and hypodiploid ALL intermediate rates (80.0% to 88.2%); and BCR-ABL1, BCR-ABL1-like and ETV6-RUNX1-like and KMT2A-rearranged ALL the worst rates (64.1% to 76.2%). All but three of the 142 patients with day-8 blood MRD <0.01% remained in remission. Among new subtypes, intensified therapy based on day-15 MRD≥1% improved outcome of DUX4-rearranged, BCR-ABL1-like, and ZNF384-rearranged ALL, and achievement of day-42 MRD<0.01% did not preclude relapse of PAX5alt, MEF2D-rearranged and ETV6-RUNX1-like ALL. Thus, new subtypes including DUX4-rearranged, PAX5alt, BCR-ABL1-like, ETV6-RUNX1-like, MEF2D-rearranged and ZNF384-rearranged ALL have important prognostic and therapeutic implications.

Clinical features and outcome of pediatric acute lymphoblastic leukemia with low peripheral blood blast cell count at diagnosis

Peripheral blood (PB) blast cell count on day 8 of prednisone therapy has been considered one of the strongest predictors of outcome in children with acute lymphoblastic leukemia (ALL). However, little is known about the clinical features and prognostic impact of PB blast cell count at diagnosis in these patients. The aim of this study was to evaluate the relationship between initial PB blast cell count and clinical prognosis of pediatric ALL.The study comprised 367 patients with ALL, aged 0 to 14 years, enrolled and treated using the Chinese Children's Leukemia Group-ALL 2008 protocol between 2011 and 2015. The majority (91.6%) of patients were B-cell precursor ALL (BCP ALL), and 8.4% were T-cell ALL (T-ALL).Patients with BCP ALL in the low PB blast cell count group (<1 × 109/L) had significantly superior survival rates to those in the high count group (≥30 × 109/L). In T-ALL, the low count group showed significantly inferior survival rates compared to both the intermediate count group (1-29.9 × 109/L) and high count group. Multivariate analysis revealed that the initial white blood cell count and minimal residual disease at the end of induction therapy were independently predictive of BCP ALL outcome, while risk stratification was shown to be an independent prognostic factor for T-ALL outcome.These results indicated that low blast cell count in PB at diagnosis was associated with different clinical outcomes in patients with BCP ALL and T-ALL, although it was not an independent outcome predictor by multivariate analysis.

Minimal residual disease in acute lymphoblastic leukemia: technical aspects and implications for clinical interpretation

Minimal residual disease (MRD) monitoring has proven to be one of the fundamental independent prognostic factors for patients with acute lymphoblastic leukemia (ALL). Sequential monitoring of MRD using sensitive and specific methods, such as real-time quantitative polymerase chain reaction (qPCR) or flow cytometry (FCM), has improved the assessment of treatment response and is currently used for therapeutic stratification and early detection. Although both FCM and qPCR yield highly consistent results with sensitivities of 10^‒4, each method has several limitations. For example, qPCR is time-consuming and laborious: designing primers that correspond to the immunoglobulin (IG) and T-cell receptor (TCR) gene rearrangements at diagnosis can take 3‒4 weeks. In addition, the evolution of additional clones beyond the first or index clone during therapy cannot be detected, which might lead to false-negative results. FCM requires experienced technicians and sometimes does not achieve a sensitivity of 10^‒4. Accordingly, a next generation sequencing (NGS)-based method has been developed in an attempt to overcome these limitations. With the advent of high-throughput NGS technologies, a more in-depth analysis of IG and/or TCR gene rearrangements is now within reach, which impacts all applications of IG/TR analysis. However, standardization, quality control, and validation of this new technology are warranted prior to its incorporation into routine practice.

Correlation of Day 8 Steroid Response with Bone Marrow Status Measured on Days 14 and 35, in Patients with Acute Lymphoblastic Leukemia Being Treated with BFM Protocol

Berlin-Frankfurt-Munster (BFM) protocol is commonly used in India for treatment of acute lymphoblastic leukemia (ALL). The present study was conducted to correlate day 8 steroid response with bone marrow status (by morphology and flow cytometry) at day 14 and day 35 of treatment. It was a prospective study which included all newly diagnosed ALL patients who visited hospital between March 2013 and February 2015 i.e. 2 years. On 8th day, the number of lymphoblasts was counted in the peripheral blood. Based on the number of blasts patients were classified as good steroid responders and poor steroid responders. Following pre-induction steroids patients were given induction therapy. During this phase on day 14 and day 35 bone marrow (BM) aspiration study was done. Later day 8 steroid response, Day 14 BM status and day 35 BM status were correlated. Results showed that there was a statistically significant correlation between day 8 steroid response and day 14 BM status (both by morphology and flow cytometry). There was no statistically significant correlation between day 8 steroid response and day 35 BM status (both by morphology and flow cytometry). There was no statistically significant correlation between day 14 and day 35 BM status (both by morphology and flow cytometry). Sensitivity and specificity of morphological evaluation of BM was much lower compared to minimal residual disease assessment by flow cytometry. There is a need to incorporate flow cytometry in risk stratification of patients who are being treated with BFM 2002 protocol.

Treatment of higher risk acute lymphoblastic leukemia in young people (CCG-1961), long-term follow-up: a report from the Children's Oncology Group

Children's Cancer Group CCG-1882 improved outcome for 1-21-year old with high risk acute lymphoblastic leukemia and Induction Day 8 marrow blasts ≥25% (slow early responders, SER) with longer and stronger post induction intensification (PII). This CCG-1961 explored alternative PII strategies. We report 10-year follow-up for patients with rapid early response (RER) and for the first time details our experience for SER patients. A total of 2057 patients were enrolled, and 1299 RER patients were randomized to 1 of 4 PII regimens: standard vs. augmented intensity and standard vs. increased length. At the end of interim maintenance, 447 SER patients were randomized to idarubicin/cyclophosphamide or weekly doxorubicin in the delayed intensification phases. The 10-year EFS for RER were 79.4 ± 2.4% and 70.9 ± 2.6% (hazard ratio = 0.65, 95% CI 0.52-0.82, p < 0.001) for augmented and standard strength PII; the 10-year OS rates were 87.2 ± 2.0% and 81.0 ± 2.2% (hazard ratio = 0.64, 95% CI 0.48-0.86, p = 0.003). Outcomes remain similar for standard and longer PII, and for SER patients assigned to idarubicin/cyclophosphamide and weekly doxorubicin. The EFS and OS advantage of augmented PII is sustained at 10 years for RER patients. Longer PII for RER patients and sequential idarubicin/cyclophosphamide for SER patients offered no advantage. CCG-1961 is the platform for subsequent COG studies.

Immunophenotypic Modulation of the Blast Cells in Childhood Acute Lymphoblastic Leukemia Minimal Residual Disease Detection

Early clearance of leukemic cells during induction therapy of childhood acute lymphoblastic leukemia (ALL) is a basis for treatment optimization. Currently, the most widely used methods for the detection of minute residual malignant cells in the bone marrow and/or peripheral blood, minimal residual disease (MRD), are PCR and flow cytometry (FCM). Immunophenotypic modulation (IM) is a well known factor that can hamper the accurate FCM analysis.

AIM

To report the IM detected by 8-color FCM during the BFM-type remission induction in 24 consecutive MRD-positive samples of children with B-cell precursor ALL and the possible implications for MRD detection.

PATIENTS AND METHODS

Between 2010 and 2012 we prospectively followed up the MRD on days 15 and 33 of induction treatment in bone marrow (BM) samples and on day 8 in peripheral blood (PB). The IM was assessed by comparative analyses of the changes in the mean fluorescence intensity of 7 highly relevant antigens expressed by the leukemic cells and normal B-lymphocytes.

RESULTS

IM occurred, to different extents, in all analyzed day 15 BM and in most day 33 BM samples. Statistically significant changes in the MFI-levels of four CDs expressed by the leukemic blasts were observed: downmodulation of CD10, CD19 and CD34 and upmodulation of CD20. No changes in the expression of CD38, CD58 and CD45 were noticed.

CONCLUSIONS

Measuring the MRD by standardized 8-color flow cytometry helps improve the monitoring of the disease, leading to better therapeutic results. However, the IM of the different antigens expressed by the leukemic blasts should be taken into consideration and cautiously analyzed.

Role of peripheral blood minimum residual disease at day 8 of induction therapy in high-risk pediatric patients with acute lymphocytic leukemia

Risk stratification and treatment intensification, based on minimal residual disease (MRD) mensurement, changed the prognosis of pediatric patients with acute lymphocytic leukemia (ALL). The main aim of this study was to investigate whether peripheral blood (PB) MRD measurement at day 8 (D8) could predict the risk stratification category determined by bone marrow (BM) MRD at day 15 (D15). The study was performed prospectively, in a cohort of 40 children with B-lineage ALL, adopting the protocol of the Brazilian Cooperative Group of the Treatment Childhood Leukemia (GBTLI-2009). MRD was detected by flow cytometry (FC) using a simplifed panel that can reliably identify MRD at early phases of induction therapy. Upon diagnosis, the proportion of low and high-risk patients, was 24:16 (60%:40%). The main result of our study demonstrated the potential of D8 MRD in anticipating of week the risk stratification of high-risk patients as determined by D15 BM MRD. In these patients D8 MRD level of 1% was able to segregate high risk fast responders from high risk slow responders (p = 0.0097). This result could represent an opportunity for early treatment intensification, as already performed in some protocols.

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.

Protracted Administration of L-Asparaginase in Maintenance Phase Is the Risk Factor for Hyperglycemia in Older Patients with Pediatric Acute Lymphoblastic Leukemia

Although L-asparaginase related hyperglycemia is well known adverse event, it is not studied whether the profile of this adverse event is affected by intensification of L-asparaginase administration. Here, we analyzed the profile of L-asparaginase related hyperglycemia in a 1,176 patients with pediatric acute lymphoblastic leukemia treated according to the Japan Association of Childhood Leukemia Study ALL-02 protocol using protracted L-asparaginase administration in maintenance phase. We determined that a total of 75 L-asparaginase related hyperglycemia events occurred in 69 patients. Although 17 events (17/1176, 1.4%) developed in induction phase, which was lower incidence than those (10–15%) in previous reports, 45 events developed during the maintenance phase with protracted L-asparaginase administration. Multivariate analysis showed that older age at onset (≥10 years) was a sole independent risk factor for L-asparaginase-related hyperglycemia (P<0.01), especially in maintenance phase. Contrary to the previous reports, obesity was not associated with L-asparaginase-related hyperglycemia. These findings suggest that protracted administration of L-asparaginase is the risk factor for hyperglycemia when treating adolescent and young adult acute lymphoblastic leukemia patients.

Minimal residual disease diagnostics in acute lymphoblastic leukemia: need for sensitive, fast, and standardized technologies

Monitoring of minimal residual disease (MRD) has become routine clinical practice in frontline treatment of virtually all childhood acute lymphoblastic leukemia (ALL) and in many adult ALL patients. MRD diagnostics has proven to be the strongest prognostic factor, allowing for risk group assignment into different treatment arms, ranging from significant treatment reduction to mild or strong intensification. Also in relapsed ALL patients and patients undergoing stem cell transplantation, MRD diagnostics is guiding treatment decisions. This is also why the efficacy of innovative drugs, such as antibodies and small molecules, are currently being evaluated with MRD diagnostics within clinical trials. In fact, MRD measurements might well be used as a surrogate end point, thereby significantly shortening the follow-up. The MRD techniques need to be sensitive (≤10(-4)), broadly applicable, accurate, reliable, fast, and affordable. Thus far, flow cytometry and polymerase chain reaction (PCR) analysis of rearranged immunoglobulin and T-cell receptor genes (allele-specific oligonucleotide [ASO]-PCR) are claimed to meet these criteria, but classical flow cytometry does not reach a solid 10(-4), whereas classical ASO-PCR is time-consuming and labor intensive. Therefore, 2 high-throughput technologies are being explored, ie, high-throughput sequencing and next-generation (multidimensional) flow cytometry, both evaluating millions of sequences or cells, respectively. Each of them has specific advantages and disadvantages.

Clinical features and prognostic significance of TCF3-PBX1 fusion gene in Chinese children with acute lymphoblastic leukemia by using a modified ALL-BFM-95 protocol

For children with precursor B (pre-B) acute lymphoblastic leukemia (ALL) with TCF3-PBX1 fusion gene, their prognosis has been a controversial topic. From January 2008 to December 2012 in our hospital, 450 patients were diagnosed as ALL. Clinical characteristics of 20 patients with TCF3-PBX1 fusion gene were analyzed retrospectively, which were classified to the intermediate-risk (IR) group according to Chinese Children Leukemia Group-2008 (CCLG-2008) risk-stratification criteria and protocol based on the backbone of BFM 95 trails. Eighty five cases without TCF3-PBX1 in the same IR group were regarded as the comparison group. There were no differences in age, gender, initial white blood cell (WBC) count, status of central nerves system (CNS) at diagnosis and complete remission (CR) rates of bone marrow (BM) between the two groups (P > .05). The 5-year probability of event-free survival (EFS) rates were 84.4 ± 15.6% and 73.5 ± 15.6% in the TCF3-PBX1 group and the comparison group (P = .35), respectively. The 5-year probability of overall survival (OS) rates were 86.0 ± 17.6% and 81.8 ± 17.6% (P = .46), respectively. Relapse rates were 10.5% and 12.9% (P = 1.00), respectively. There were not cases with CNS relapse in the TCF3-PBX1 group. When intensive chemotherapy was used, the TCF3-PBX1 was associated with a favorable outcome in childhood pre-B ALL.

Improving the identification of high risk precursor B acute lymphoblastic leukemia patients with earlier quantification of minimal residual disease

The stratification of patients with acute lymphoblastic leukemia (ALL) into treatment risk groups based on quantification of minimal residual disease (MRD) after induction therapy is now well accepted but the relapse rate of about 20% in intermediate risk patients remains a challenge. The purpose of this study was to further improve stratification by MRD measurement at an earlier stage. MRD was measured in stored day 15 bone marrow samples for pediatric patients enrolled on ANZCHOG ALL8 using Real-time Quantitative PCR to detect immunoglobulin and T-cell receptor gene rearrangements with the same assays used at day 33 and day 79 in the original MRD stratification. MRD levels in bone marrow at day 15 and 33 were highly predictive of outcome in 223 precursor B-ALL patients (log rank Mantel-Cox tests both P<0.001) and identified patients with poor, intermediate and very good outcomes. The combined use of MRD at day 15 (≥1×10⁻²) and day 33 (≥5×1⁻⁵) identified a subgroup of medium risk precursor B-ALL patients as poor MRD responders with 5 year relapse-free survival of 55% compared to 84% for other medium risk patients (log rank Mantel-Cox test, P = 0.0005). Risk stratification of precursor B-ALL but not T-ALL could be improved by using MRD measurement at day 15 and day 33 instead of day 33 and day 79 in similar BFM-based protocols for children with this disease.

Detection of MRD may predict the outcome of patients with Philadelphia chromosome-positive ALL treated with tyrosine kinase inhibitors plus chemotherapy

From 2001 to 2011, 122 patients with newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia were treated with chemotherapy + imatinib (n = 54) or + dasatinib (n = 68). One hundred fifteen (94%) achieved complete remission (CR) including 101 patients who achieved it with only 1 induction course and had at least 1 minimal residual disease (MRD) assessment; 25 patients underwent an allogeneic stem cell transplant in first CR and were excluded, leaving 76 patients as the subject of this report. MRD monitoring by multiparameter flow cytometry (MFC) and real-time quantitative polymerase chain reaction (PCR) was performed at the end of induction and at ~3-month intervals thereafter. Median age was 54 years (range, 21-84 years). There was no difference in survival by achievement of at least a major molecular response (MMR; BCR-ABL/ABL < 0.1%) at CR (P = .22). Patients achieving MMR at 3, 6, 9, and 12 months had a better survival (P = .02, .04, .05, and .01, respectively). Negative MFC at CR did not predict for improved survival (P = .2). At 3 and 12 months, negative MRD by MFC was associated with improved survival (P = .04 and .001). MRD monitoring by PCR and MFC identifies patients who benefit from treatment intensification in first CR.

Screening for coagulopathy and identification of children with acute lymphoblastic leukemia at a higher risk of symptomatic venous thrombosis: an AIEOP experience

INTRODUCTION

Venous thromboembolic events (VTEs) are frequent complications of childhood acute lymphoblastic leukemia (ALL) treatment. The aim of the study was to evaluate the rate of symptomatic VTEs in children with ALL and the predictive value of clinical and biological factors and routine monitoring of coagulation parameters in identifying children at a higher risk of this complication.

MATERIALS AND METHODS

Between September 2000 and July 2006, 2042 children (≥1 and younger than 18 y) with newly diagnosed ALL were enrolled in Italy in the AIEOP (Italian Association of Pediatric Hematology and Oncology)-BFM (Berlin-Frankfurt-Muenster) ALL 2000 trial. Patients with symptomatic VTEs (deep venous thromboses or cerebral venous thromboses) were identified after a careful review of clinical records. The impact of coagulation derangement at the onset of VTEs was evaluated by a nested case-control study.

RESULTS

Forty-eight (2.4%) children presented with a VTE. The rate of VTEs was higher in male patients (P=0.001); patients randomized to receive dexamethasone tended to have a higher rate of VTE compared with those who received prednisone (P=0.10). The coagulation derangement at the onset of VTE was not associated with VTE occurrence. The prevalence of a factor V Leiden G1691A mutation and the prothrombin G20210A variant was higher in children with VTE than that expected in the general population.

Treatment of relapsed acute lymphoblastic leukemia: approaches used by pediatric oncologists and bone marrow transplant physicians

BACKGROUND

Management of relapsed B-precursor acute lymphoblastic leukemia (ALL) is challenging and varied. We hypothesized that treatment approaches differ between pediatric oncologists and bone marrow transplant (BMT) physicians.

PROCEDURE

A survey addressing management of relapsed ALL was sent to pediatric oncologists (n = 883) and BMT (n = 86) physicians across North America.

RESULTS

A number of similarities in treatment approaches were identified including: choice of chemotherapy for re-induction/consolidation, preference for unrelated donors (URDs) in very early marrow relapse and the choice to not use URD donors in late marrow relapse. However, differences between the two disciplines were noted. For patients who relapsed 18-36 months from diagnosis, the majority of oncologists (53.7%) would retreat with chemotherapy while a majority BMT physicians (70.3%) recommended URD transplant (P < 0.001). Oncologists were also less likely to use minimal residual disease (MRD) in relapse assessment compared to BMT physicians (52% vs. 67.2%; P = 0.028) and more oncologists believed MRD testing was experimental and/or not proven in relapsed ALL (27.1% vs. 12.3%; P = 0.011).

CONCLUSIONS

This study highlights management differences in children with ALL between pediatric oncologists and BMT physicians, identifying opportunities for collaborative clinical trials.

Early Response to Dexamethasone as Prognostic Factor: Result from Indonesian Childhood WK-ALL Protocol in Yogyakarta

Early response to treatment has been shown to be an important prognostic factor of childhood acute lymphoblastic leukemia (ALL) patients in Western studies. We studied this factor in the setting of a low-income province in 165 patients treated on Indonesian WK-ALL-2000 protocol between 1999 and 2006. Poor early response, defined as a peripheral lymphoblasts count of ≥1000/μL after 7 days of oral dexamethasone plus one intrathecal methotrexate (MTX), occurred in 19.4% of the patients. Poor responders showed a higher probability of induction failures compared to good responders (53.1% versus 23.3%, P < 0.01), higher probability of resistant disease (15.6% versus 4.5%, P = 0.02), shorter disease-free survival (P = 0.034; 5-year DFS: 24.9% ± 12.1% versus 48.6% ± 5.7%), and shorter event-free survival (P = 0.002; 5-year EFS: 9.7% ± 5.3% versus 26.3% ± 3.8%). We observed that the percentage of poor responders in our setting was higher than reported for Western countries with prednisone or prednisolone as the steroids. The study did not demonstrate a significant additive prognostic value of early response over other known risk factors (age and white blood cell count) for DFS and only a moderately added value for EFS.

Detection and monitoring of normal and leukemic cell populations with hierarchical clustering of flow cytometry data

Flow cytometry is a valuable tool in research and diagnostics including minimal residual disease (MRD) monitoring of hematologic malignancies. However, its gradual advancement toward increasing numbers of fluorescent parameters leads to information rich datasets, which are challenging to analyze by standard gating and do not reflect the multidimensionality of the data. We have developed a novel method to analyze complex flow cytometry data, based on hierarchical clustering analysis (HCA) but with a new underlying algorithm, using Mahalanobis distance measure. HCA is scalable to analyze complex multiparameter datasets (here demonstrated on up to 12 color flow cytometry and on a 20-parameter synthetic dataset). We have validated this method by comparison with standard gating approaches when performed independently by expert cytometrists. Acute lymphoblastic leukemia blast populations were analyzed in diagnostic and follow-up datasets (n = 123) from three centers. HCA results correlated very well (Passing-Bablok correlation coefficient = 0.992, slope = 1, intercept = -0.01) with standard gating data obtained by the I-BFM FLOW-MRD study group. To further improve the performance in follow-up samples with low MRD levels and to automate MRD detection, we combined HCA with support vector machine (SVM) learning. HCA in combination with SVM provides a novel diagnostic tool that not only allows analysis of increasingly complex flow cytometry data but also is less observer-dependent compared with classical gating and has potential for automation.

Minimal residual disease in peripheral blood at day 15 identifies a subgroup of childhood B-cell precursor acute lymphoblastic leukemia with superior prognosis

BACKGROUND

Most minimal residual disease-directed treatment interventions in current treatment protocols for acute lymphoblastic leukemia are based on bone marrow testing, which is a consequence of previous studies showing the superiority of bone marrow over peripheral blood as an investigational material. Those studies typically did not explore the prognostic impact of peripheral blood involvement and lacked samples from very early time points of induction.

DESIGN AND METHODS

In this study, we employed real-time quantitative polymerase chain reaction analysis to examine minimal residual disease in 398 pairs of blood and bone marrow follow-up samples taken from 95 children with B-cell precursor acute lymphoblastic leukemia treated with the ALL IC-BFM 2002 protocol.

RESULTS

We confirmed the previously published poor correlation between minimal residual disease in blood and marrow at early treatment time points, with levels in bone marrow being higher than in blood in most samples (median 7.9-fold, range 0.04-8,293-fold). A greater involvement of peripheral blood at diagnosis was associated with a higher white blood cell count at diagnosis (P=0.003) and with enlargement of the spleen (P=0.0004) and liver (P=0.05). At day 15, a level of minimal residual disease in blood lower than 10(-4) was associated with an excellent 5-year relapse-free survival in 78 investigated patients (100% versus 69 ± 7%; P=0.0003). Subgroups defined by the level of minimal residual disease in blood at day 15 (high-risk: ≥ 10(-2), intermediate-risk: <10(-2) and ≥ 10(-4), standard-risk: <10(-4)) partially correlated with bone marrow-based stratification described previously, but the risk groups did not match completely. No other time point analyses were predictive of outcome in peripheral blood, except for a weak association at day 8.

CONCLUSIONS

Minimal residual disease in peripheral blood at day 15 identified a large group of patients with an excellent prognosis and added prognostic information to the risk stratification based on minimal residual disease at day 33 and week 12.

Xenografts of highly resistant leukemia recapitulate the clonal composition of the leukemogenic compartment

Clonal evolution of the leukemogenic compartment may contribute to alter the therapeutic response in acute lymphoblastic leukemia (ALL). Using xenotransplantation of primary leukemia cells, we evaluated the phenotypic and genetic composition of de novo resistant very high risk precursor B-cell ALL, a subgroup defined by the persistence of minimal residual disease despite intensive chemotherapy. Analysis of copy number alterations (CNAs) showed that the xenografted leukemia, even when reconstituted from 100 cells, remained highly related to the diagnostic sample, with minor changes in CNAs, mostly deletions, emerging in most cases in the first passage into mice. At the single-cell level, the pattern of monoallelic and biallelic deletions of the CDKN2A locus revealed distinct leukemia subpopulations, which were reproducibly tracked in xenografts. In most very high risk ALL cases, the predominant diagnostic clones were reconstituted in xenografts, as shown by multiplex polymerase chain reaction analysis of immunoglobulin and T-cell receptor loci. In other cases, the pattern in CNAs and immunoglobulin and T-cell receptor rearrangement was less concordant in xenografts, suggesting the outgrowth of subclones. These results unequivocally demonstrate the existence of clonally closely related but distinct subsets of leukemia initiating cells in ALL, which has important implications for drug development and preclinical disease modeling.

Prospective comparison of two flow cytometry methodologies for monitoring minimal residual disease in a multicenter treatment protocol of childhood acute lymphoblastic leukemia

BACKGROUND

Minimal residual disease (MRD) is a powerful prognostic indicator in childhood acute lymphoblastic leukemia (ALL). Multiparametric flow cytometry (FC) is a rapid and sensitive methodology for detection of MRD, applicable for most patients and is being incorporated in multicenter treatment protocols. The influence of different techniques and of individual interpretation of data on the interlaboratory variability in FC-MRD determinations has not been described.

METHODS

We compared FC-MRD of identical bone marrow samples processed as either Ficoll separated mononuclear cells or lyse and wash nucleated cells (NC) in two central laboratories of a national multicenter childhood ALL study. A total of 290 samples at diagnosis and 494 follow-up samples (Day-15 n = 261; Day-33 n = 233) were analyzed. A group of 52 paired list mode data (LMD) of D-15 and D-33 samples was blindly reanalyzed by both laboratories.

RESULTS

Pearson correlations for all samples of D-15 (n = 261) and D-33 (n = 233) were 0.875 and 0.82, respectively (P < 0.001), being lower for T-ALL 0.716 and 0.719, respectively. Quantitative concordance defined as less than 0.5 log difference in MRD measured by the two methodologies was 80.8% at D-15 but only in 57.9% at D-33. Reanalysis of LMD revealed that data interpretation explained half of the discordance.

CONCLUSIONS

FC-MRD analysis of childhood ALL is a robust method during the earliest phases of induction therapy in a multicentric setting. Standardization of data analysis could improve about half of the discordance between different technical approaches.

Pro-apoptotic activity of α-bisabolol in preclinical models of primary human acute leukemia cells

Background

We previously demonstrated that the plant-derived agent α-bisabolol enters cells via lipid rafts, binds to the pro-apoptotic Bcl-2 family protein BID, and may induce apoptosis. Here we studied the activity of α-bisabolol in acute leukemia cells.

Methods

We tested ex vivo blasts from 42 acute leukemias (14 Philadelphia-negative and 14 Philadelphia-positive B acute lymphoid leukemias, Ph^-/Ph⁺B-ALL; 14 acute myeloid leukemias, AML) for their sensitivity to α-bisabolol in 24-hour dose-response assays. Concentrations and time were chosen based on CD34⁺, CD33⁺my and normal peripheral blood cell sensitivity to increasing α-bisabolol concentrations for up to 120 hours.

Results

A clustering analysis of the sensitivity over 24 hours identified three clusters. Cluster 1 (14 ± 5 μM α-bisabolol IC₅₀) included mainly Ph^-B-ALL cells. AML cells were split into cluster 2 and 3 (45 ± 7 and 65 ± 5 μM IC₅₀). Ph⁺B-ALL cells were scattered, but mainly grouped into cluster 2. All leukemias, including 3 imatinib-resistant cases, were eventually responsive, but a subset of B-ALL cells was fairly sensitive to low α-bisabolol concentrations. α-bisabolol acted as a pro-apoptotic agent via a direct damage to mitochondrial integrity, which was responsible for the decrease in NADH-supported state 3 respiration and the disruption of the mitochondrial membrane potential.

Conclusion

Our study provides the first evidence that α-bisabolol is a pro-apoptotic agent for primary human acute leukemia cells.

Multiparameter flow cytometry in the diagnosis and management of acute leukemia

CONTEXT

Timely and accurate diagnosis of hematologic malignancies is crucial to appropriate clinical management. Acute leukemias are a diverse group of malignancies with a range of clinical presentations, prognoses, and preferred treatment protocols. Historical classification systems relied predominantly on morphologic and cytochemical features, but currently, immunophenotypic, cytogenetic, and molecular data are incorporated to define clinically relevant diagnostic categories. Multiparameter flow cytometry provides rapid and detailed determination of antigen expression profiles in acute leukemias which, in conjunction with morphologic assessment, often suggests a definitive diagnosis or a narrow differential. Many recurrent molecular or cytogenetic aberrations are associated with distinct immunophenotypic features, and therefore flow cytometry is an important tool to direct further testing. In addition, detection of specific antigens may have prognostic or therapeutic implications even within a single acute leukemia subtype. After initial diagnosis, a leukemia's immunophenotypic fingerprint provides a useful reference to monitor response to therapy, minimal residual disease, and recurrence.

OBJECTIVE

To provide an overview of the application of flow cytometric immunophenotyping to the diagnosis and management of acute leukemias, including salient features of those entities described in the 2008 World Health Organization classification.

DATA SOURCES

Published articles pertaining to flow cytometry, acute leukemia classification, and experiences of a reference flow cytometry laboratory.

CONCLUSION

Immunophenotypic evaluation is essential to accurate diagnosis and classification of acute leukemia. Multiparameter flow cytometry provides a rapid and effective means to collect this information, as well as providing prognostic information and a modality for minimal residual disease evaluation.

Automated pattern-guided principal component analysis vs expert-based immunophenotypic classification of B-cell chronic lymphoproliferative disorders: a step forward in the standardization of clinical immunophenotyping

Immunophenotypic characterization of B-cell chronic lymphoproliferative disorders (B-CLPD) is becoming increasingly complex due to usage of progressively larger panels of reagents and a high number of World Health Organization (WHO) entities. Typically, data analysis is performed separately for each stained aliquot of a sample; subsequently, an expert interprets the overall immunophenotypic profile (IP) of neoplastic B-cells and assigns it to specific diagnostic categories. We constructed a principal component analysis (PCA)-based tool to guide immunophenotypic classification of B-CLPD. Three reference groups of immunophenotypic data files-B-cell chronic lymphocytic leukemias (B-CLL; n = 10), mantle cell (MCL; n = 10) and follicular lymphomas (FL; n = 10)--were built. Subsequently, each of the 175 cases studied was evaluated and assigned to either one of the three reference groups or to none of them (other B-CLPD). Most cases (89%) were correctly assigned to their corresponding WHO diagnostic group with overall positive and negative predictive values of 89 and 96%, respectively. The efficiency of the PCA-based approach was particularly high among typical B-CLL, MCL and FL vs other B-CLPD cases. In summary, PCA-guided immunophenotypic classification of B-CLPD is a promising tool for standardized interpretation of tumor IP, their classification into well-defined entities and comprehensive evaluation of antibody panels.

Matrix-assisted autologous chondrocyte implantation into a 14cm(2) cartilage defect, caused by steroid-induced osteonecrosis

Modern chemotherapy protocols have improved the prognosis for acute lymphoblastic leukaemia (ALL), one of the most common paediatric malignancies, but their high-dose corticosteroids lead to osteonecrosis in up to 9% of ALL patients. A 13.5-year-old female patient developed massive osteonecrosis of the right knee after successful ALL treatment. She presented at the age of 17.5 years as a candidate for knee arthroplasty after conservative treatment had failed. Magnetic Resonance Imaging (MRI) revealed severe osteonecrosis, with the cartilage layer of the medial femoral condyle completely detached from the bone. We preferred to attempt a two-step biological reconstruction in this young patient, with arthroscopy of the right knee joint and removal of the dissected cartilage layer of the medial condyle. Matrix-assisted autologous chondrocyte implantation (MACI) was performed with harvested chondrocytes after imaging had indicated vital bone remodelling. Rehabilitation was according to MACI guidelines and after 5.5 years, the patient shows continuous clinical improvement and is satisfied with the result. The Lysholm score improved from 45 to 99 and Tegner's activity score from 1 to 4. MRI follow-up showed a solid cartilage layer covering the medial condyle as a result of bone and chondral regeneration. Even if this approach had failed, bone remodelling would have still provided better conditions for knee arthroplasty.

CD11b is a therapy resistance- and minimal residual disease-specific marker in precursor B-cell acute lymphoblastic leukemia

A consistently increased mRNA expression of the adhesion receptor CD11b is a hallmark of the reported genomewide gene expression changes in precursor B-cell acute lymphoblastic leukemia (PBC-ALL) after 1 week of induction therapy. To investigate its clinical relevance, CD11b protein expression in leukemic blasts has been prospectively measured at diagnosis (159 patients) and during therapy (53 patients). The initially heterogeneous expression of CD11b inversely correlated with cytoreduction rates measured at clinically significant time points of induction therapy in the ALL-Berlin-Frankfurt-Münster 2000 protocol. CD11b positivity conferred a 5-fold increased risk of minimal residual disease (MRD) after induction therapy (day 33) and of high-risk group assignment after consolidation therapy (day 78). In the multivariate analysis CD11b expression was an independent prognostic factor compared with other clinically relevant parameters at diagnosis. During therapy, CD11b expression increased early in most ALL cases and remained consistently increased during induction/consolidation therapy. In more than 30% of MRD-positive cases, the CD11b expression on blast cells exceeded that of mature memory B cells and improved the discrimination of residual leukemic cells from regenerating bone marrow. Taken together, CD11b expression has considerable implications for prognosis, treatment response monitoring, and MRD detection in childhood PBC-ALL.

Long-term results of St Jude Total Therapy Studies 11, 12, 13A, 13B, and 14 for childhood acute lymphoblastic leukemia

We analyzed the long-term outcome of 1011 patients treated in five successive clinical trials (Total Therapy Studies 11, 12, 13A, 13B, and 14) between 1984 and 1999. The event-free survival improved significantly (P=0.003) from the first two trials conducted in the 1980s to the three more recent trials conducted in the 1990s. Approximately 75% of patients treated in the 1980s and 80% in the 1990s were cured. Early intensive triple intrathecal therapy, together with more effective systemic therapy, including consolidation and reinduction treatment (Studies 13A and 13B) as well as dexamethasone (Study 13B), resulted in a very low rate of isolated central nervous system (CNS) relapse rate (<2%), despite the reduced use of cranial irradiation. Factors consistently associated with treatment outcome were age, leukocyte count, immunophenotype, DNA index, and minimal residual disease level after remission induction treatment. Owing to concerns about therapy-related secondary myeloid leukemia and brain tumors, in our current trials we reserve the use of etoposide for patients with refractory or relapsed leukemia undergoing hematopoietic stem cell transplantation, and cranial irradiation for those with CNS relapse. The next main challenge is to further increase cure rates while improving quality of life for all patients.

Long-term results of the pediatric oncology group studies for childhood acute lymphoblastic leukemia 1984-2001: a report from the children's oncology group

From 1984 to 2001, the Pediatric Oncology Group (POG) conducted 12 acute lymphoblastic leukemia (ALL) studies. Ten-year event-free survival (EFS) for patients >12 months of age with B-precursor ALL on acute leukemia in children 14, 15 and 16 series were 66.7+/-1.2%, 68.1+/-1.4% and 73.2+/-2.1%, respectively. Intermediate dose methotrexate (ID MTX; 1 g/m(2)) improved outcomes for standard risk patients (10-year EFS 77.5+/-2.7% vs 66.3+/-3.1% for oral MTX). Neither MTX intensification (2.5 g/m(2)) nor addition of cytosine arabinoside/daunomycin/teniposide improved outcomes for higher risk patients. Intermediate dose mercaptopurine (1 g/m(2)) failed to improve outcomes for either group. Ten-year EFS for patients with T-cell ALL, POG 8704 and 9404 were 49.1+/-3.1% and 72.2+/-4.7%, respectively. Intensive asparaginase (10-year EFS 61.8 vs 42.7%) and high-dose MTX (5 g/m(2)) (10-year EFS 78.0 vs 65.8%) improved outcomes. There was a non-significant improvement in EFS for infants (10-year EFS 17.7+/-7.2-31.9+/-8.3%). Prognostic indicators for B-precursor ALL were age and WBC at diagnosis, gender, central nervous system disease, DNA index and cytogenetic abnormalities. Only gender was prognostic in T-cell ALL. In infants, WBC and MLL translocation were linked to inferior outcome.

Detection of residual B precursor lymphoblastic leukemia by uniform gating flow cytometry

BACKGROUND

Residual disease (RD) is an important prognostic factor in acute lymphoblastic leukemia (ALL). Flow cytometry (FC)-based RD detection is easy to perform, but interpretation requires expert analysis due to individual differences among patients.

PROCEDURE

We focused at the design of standardized and reproducible RD monitoring in ALL. RD was investigated by a uniform gating strategy, which was designed internationally and tested in one center by Ig/TCR rearrangements.

RESULTS

For each gate, positivity cutoff value was assigned using quantification of non-leukemic background. Comparing to Ig/TCR at 0.1% level, 80 of 103 specimens were correctly diagnosed by FC. The predictive value of FC RD at day 15 was then analyzed. In B lineage ALL, day 15 FC significantly correlated with Ig/TCR results at day 33 and/or week 12 (P < 0.01). No significant correlation was found in T lineage ALL.

CONCLUSIONS

Thus, FC with preset uniform gating at day 15 predicts PCR-detectable MRD in B precursor ALL. Presented data may be used to define new polychromatic cytometric diagnostics of MRD including semiautomatic assessment. Pediatr Blood Cancer 2010; 54:62-70. (c) 2009 Wiley-Liss, Inc.

Long-term results of the Italian Association of Pediatric Hematology and Oncology (AIEOP) Studies 82, 87, 88, 91 and 95 for childhood acute lymphoblastic leukemia

We analyzed the long-term outcome of 4865 patients treated in Studies 82, 87, 88, 91 and 95 for childhood acute lymphoblastic leukemia (ALL) of the Italian Association of Pediatric Hematology and Oncology (AIEOP). Treatment was characterized by progressive intensification of systemic therapy and reduction of cranial radiotherapy. A progressive improvement of results with reduction of isolated central nervous system relapse rate was obtained. Ten-year event-free survival increased from 53% in Study 82 to 72% in Study 95, whereas survival improved from 64 to 82%. Since 1991, all patients were treated according to Berlin-Frankfurt-Muenster (BFM) ALL treatment strategy. In Study 91, reduced treatment intensity (25%) yielded inferior results, but intensification of maintenance with high-dose (HD)-L-asparaginase (randomized) allowed to compensate for this disadvantage; in high-risk patients (HR, 15%), substitution of intensive polychemotherapy blocks for conventional BFM backbone failed to improve results. A marked improvement of results was obtained in HR patients when conventional BFM therapy was intensified with three polychemotherapy blocks and double delayed intensification (Study 95). The introduction of minimal residual disease monitoring and evaluation of common randomized questions by AIEOP and BFM groups in the protocol AIEOP-BFM-ALL 2000 are expected to further ameliorate treatment of children with ALL.

Response to glucocorticoids and toxicity in childhood acute lymphoblastic leukemia: role of polymorphisms of genes involved in glucocorticoid response

BACKGROUND

Glucocorticoids (GCs) play a fundamental role in the treatment of pediatric acute lymphoblastic leukemia (ALL), but therapy with these agents often results in a number of severe side effects. The aim of our study was to evaluate the association between polymorphisms of genes encoding for proteins involved in the pharmacokinetics/pharmacodynamics of these drugs and the occurrence of side effects, in particular infections, in a small population of ALL children.

PROCEDURE

Common polymorphisms of NR3C1, ABCB1, glutathione-S-transferase (GST)-M1, GST-P1, GST-T1, and IL-10 genes were analyzed in 36 pediatric patients with ALL, treated according to the AIEOP-BMF ALL 2000 study protocol. Toxicities occurring during the induction and reinduction periods were assessed and their association with genotypes was evaluated.

RESULTS

In univariate analysis, the risk of severe infections was increased in subjects with the GST-M1 null genotype, while patients with the GST-M1 normal genotype had significantly more moderate degree infections. The results were confirmed by multivariate analysis. Selection from the reference models of independent variables based on Akaike Information Criteria (AIC) scores maintained the GST-M1 genotype variable in the model to predict severe infections, and the ABCB1 C3435T and GST-M1 genotype variables in the model for moderate infections.

CONCLUSIONS

GST-M1 genotype may influence the severity of infections in ALL children during GC administration.