Minimal residual disease in acute lymphoblastic leukemia

Trends in childhood cancer: Incidence and survival analysis over 45 years of SEER data

BACKGROUND

The SEER Registry contains U.S. cancer statistics. To assess trends in incidence and survival and the impact of demographic factors among pediatric patients with cancer, we assessed nearly 5 decades (1975-2019) of data.

METHODS

All patients below the age of 20 with histology-confirmed malignancy were studied. Kaplan-Meier survival curves were generated to evaluate survival trends across treatment periods and ICCC classes. JoinPoint analysis was conducted to identify changes in incidence and survival.

RESULTS

The incidence of childhood cancer increased from 14.23 cases per 100,000 children in 1975-1979 to 18.89 in 2010-2019, with an average annual percent change of 0.73. This rise was more pronounced in several cancers, including leukemias, lymphomas, brain tumors, hepatic tumors, and gonadal germ cell tumors. Age-adjusted cancer mortality decreased from 4.9 to 2.3 per 100,000. Cancer-related mortality was consistently higher in boys than in girls, and in Black children than in White children. Survival significantly improved, with 5- and 10-year survival rates rising from 63.1% to 85.2% and from 58.8% to 82.7%, respectively. Leukemias showed a substantial increase in 5-year survival from 48.2% ± 1.7% to 85.1% ± 0.4% in 2010-2019. Lymphomas also showed significant improvement, with survival increasing from 72.9% ± 1.7% to 94.2% ± 0.3%. Despite these improvements, the survival of CNS tumors, bone tumors, and sarcomas remained suboptimal, with 5-year survival estimates of approximately 60%. Our joinpoint analysis confirmed our findings but revealed an interesting increase in the incidence of lymphomas limited to the years between 2005 and 2014.

CONCLUSION

This research elucidates advancements in survival among pediatric patients with cancer. The results offer critical perspectives on pediatric oncology, highlighting the imperative for ongoing innovation in therapeutics. Although the increase in incidence may partially stem from enhanced diagnostic capabilities and more comprehensive registration processes, the underlying causes remain unclear.

Microfluidic Affinity Selection of B-Lineage Cells from Peripheral Blood for Minimal Residual Disease Monitoring in Pediatric B-Type Acute Lymphoblastic Leukemia Patients

Assessment of minimal residual disease (MRD) is the most powerful predictor of outcome in B-type acute lymphoblastic leukemia (B-ALL). MRD, defined as the presence of leukemic cells in the blood or bone marrow, is used for the evaluation of therapy efficacy. We report on a microfluidic-based MRD (MF-MRD) assay that allows for frequent evaluation of blood for the presence of circulating leukemia cells (CLCs). The microfluidic chip affinity selects B-lineage cells, including CLCs using anti-CD19 antibodies poised on the wall of the microfluidic chip. Affinity-selected cells are released from the capture surface and can be subjected to immunophenotyping to enumerate the CLCs, perform fluorescence in situ hybridization (FISH), and/or molecular analysis of the CLCs' mRNA/gDNA. During longitudinal testing of 20 patients throughout induction and consolidation therapy, the MF-MRD performed 116 tests, while only 41 were completed with multiparameter flow cytometry (MFC-MRD) using a bone marrow aspirate, as standard-of-care. Overall, 57% MF-MRD tests were MRD(+) as defined by CLC numbers exceeding a threshold of 5 × 10-4%, which was determined to be the limit of quantitation. Above a threshold of 0.01%, MFC-MRD was positive in 34% of patients. The MF offered the advantage of the opportunity for efficiently processing small volumes of blood (2 mL), which is important in the care of pediatric patients, especially infants. The minimally invasive means of blood collection are of high value when treating patients whose MRD is typically tested using an invasive bone marrow biopsy. MF-MRD detection can be useful for stratification of patients into risk groups and monitoring of patient well-being after completion of treatment for early recognition of potential impending disease recurrence.

Liquid biopsy for assessment of RFS (recurrence-free survival) in NSCLC (non-small cell lung cancer) patients post-treatment through circulating tumour DNA detection: A meta-analysis

Background

One of the main techniques for diagnosing lung cancer is still tissue biopsy. The more recent liquid biopsy technique includes the assessment of fragments of cfDNA, ctDNA, and CTCs, which are released by tumour cells and act as biomarkers. After compiling information from the existing literature, we conducted a statistical analysis to evaluate the prognosis and recurrence of NSCLC post-treatment using ctDNA levels.

Method

Based on predefined inclusion and exclusion criteria, published studies between 2000 and 2022 from electronic databases with statistical data on ctDNA levels for NSCLC were included. Then, using PRISMA guidelines, we carried out a systematic review of those studies.

Result

A total of 7 studies were included in the analysis, and we found a correlation of ctDNA levels for determination of prognosis and recurrence after treatment in NSCLC. Meta-analysis was performed using RevMan version 5.4. A P-value of less than 0.05 was considered significant. Studies were divided into three groups: <1 week post-surgery, one week to 3 months post-surgery, and > three months post-surgery. Analysis showed that in <1-week post-surgery group, ctDNA-negative post-treatment detection had an HR of 4.85 (95 % CI: 2.41 to 9.77; p=<0.0001, I2 = 0 %) for recurrence-free survival compared to ctDNA-positive post-treatment detection. Similar findings were obtained for one week to 3 months and > three months group, with HR of 5.27 (95 % CI: 3.62 to 7.67; p=<0.00001, I2 = 11 %) and HR of 6.62 (95 % CI: 2.85 to 15.35; p=<0.0001, I2 = 64 %) respectively.

Conclusion

According to our meta-analysis, patients with NSCLC who were ctDNA negative after surgery had a significantly longer recurrence-free survival than those who were ctDNA positive. As a result, liquid biopsy used to measure ctDNA levels is a useful non-invasive technique to assess the prognosis in such patients. The early detection of recurrence may also allow timely therapeutic intervention, leading to better outcomes.

Minimal Residual Disease Detection Using Gene Scanning Analysis, Fluorescent Fragment Analysis, and Capillary Electrophoresis for IgH Rearrangement in Adult B-Lineage Acute Lymphoblastic Leukemia: A Cross-Sectional Study

OBJECTIVE

Minimal residual disease (MRD) is considered the greatest prognostic factor in acute lymphoblastic leukemia (ALL). MRD is a valuable tool for anticipating impending relapse and treatment response assessment. The objective of the present study was to investigate whether the detection of IgH gene rearrangement using polymerase chain reaction (PCR)-based GeneScan analysis could be a complementary method to monitor MRD along with the quantitative realtime PCR (qPCR).

MATERIALS AND METHODS

In this cross-sectional study, we valued the MRD levels, based on the GeneScanning analysis (GSA), and then compared the data with quantitative real-time polymerase chain reaction at different time points in peripheral blood (PB) samples of adult B-lineage ALL patients (n=35). The specific polymerase chain reaction (PCR) primers for IGH gene FR-1 and fluorescence-labeled J-primer were used and analyzed by capillary gel electrophoresis on a sequencer. The results of this study were compared with the previously reported MRD results obtained by the IGH rearrangements allele-specific oligonucleotide (ASO) -qPCR methods.

RESULTS

The total concordance rate was 86.7%, with a P<0.001. MRD results obtained by GSA and ASO-qPCR methods were concordant in all diagnostic samples and samples on the 14th and 28th days of induction therapy. The results of these 2.5 years' follow-ups demonstrated a significant correlation between the two techniques (r=0.892, P<0.001).

CONCLUSION

It seems that the PCR-based GeneScan analysis of IGH gene rearrangement detection may be a valuable molecular technique to distinguish monoclonality from polyclonality. And also, it may be a precise tool to detect the residual leukemic DNA in the PB follow-up samples of patients.

The prognostic significance of hematogones in childhood B-cell acute lymphoblastic leukemia

BACKGROUND

Recent studies have demonstrated hematogones (HGs) expansion to be associated with favorable outcomes in hematological diseases, especially in patients with acute myeloid leukemia and patients undergoing hematopoietic stem cell transplantation. Acute lymphoblastic leukemia (ALL) is the most common form of cancer in children. As of now, minimal residual disease (MRD) remains the most compelling independent prognostic factor in childhood ALL. There is need for more prognostic tools for evaluating relapse risk.

PROCEDURE

The goal of this study was to assess the prognostic value of HGs on relapse-free survival (RFS) and overall survival (OS) in childhood ALL. In this prospective cohort study, a total of 122 subjects with definitive diagnosis of precursor B lymphoblastic leukemia were evaluated. Flow cytometric HG detection was performed in bone marrow aspirates after induction and consolidation therapy.

RESULTS

The median follow-up period of patients was 35.5 ± 9.4 (SD) months. Patients who had at least 1.0% HGs had a significantly better RFS (p = .023). Moreover, univariate and multivariate analyses confirmed that positive HGs were independently associated with longer RFS (unadjusted model: hazard ratio = 0.33, 95% CI = 0.12-0.91, p = .031; adjusted model: hazard ratio = 0.30, 95% CI = 0.11-0.82, p = .020).

CONCLUSIONS

Along with the role of MRD, our study shows the significance of HGs as an independent prognostic factor. The results indicate the independent prognostic value of HGs on RFS after adjustment for other prognostic factors, and can be beneficial for risk stratification and treatment modifications amongst pediatric B-cell ALL patients.

Thiotepa, busulfan and fludarabine conditioning-regimen is a promising approach for older adult patients with acute lymphoblastic leukemia treated with allogeneic stem cell transplantation

For acute lymphoblastic leukemia (ALL) patients, total body irradiation (TBI)- based conditioning regimens are the first choice specially in young population. However, several studies have shown an equivalence in clinical outcomes with thiotepa-based conditioning regimen. We performed a retrospective study to evaluate the outcome of adult ALL patients who received allogeneic hematopoietic stem cell transplantation (allo-HCT) with a thiotepa-busulfan-fludarabine (TBF) myeloablative conditioning regimen with reduced toxicity. Fifty-five patients received a TBF regimen. The median age of the patients was 51 years (range, 17 to 72.4). Most patients had a diagnosis of B-ALL (93%) with 7% having T-ALL. Two - and 5-year overall survival was 73.2% and 64%, respectively. At 2 years, leukemia-free survival and GVHD-free, relapse-free survival were 59.5% and 57.6%, and at 5 years, 53.4% and 51.8%, respectively. The 5-year non-relapse mortality was 15%. The day 180 cumulative incidence (CI) of grade II-IV acute GVHD and grade III-IV acute GVHD were 38.2% and 5.5%, respectively. At 2 years, the CI of chronic GVHD and extensive chronic GVHD was 16.9% and 1.9%, respectively. Our study results do suggest that using TBF as the conditioning regimen in adult ALL patients is a promising option with acceptable toxicity.

Targeting Apoptosis in ALL

PURPOSE OF REVIEW

While the treatment of acute lymphoblastic leukemia (ALL) has improved significantly over the last 30 years, the majority of adult patients will have their disease relapse. The BCL-2 gene was initially discovered from follicular lymphoma research; however, the BH3 family of proteins has is emerging to be crucial in patients with ALL due to their reliance on the balance of these pro-apoptotic and anti-apoptotic proteins in the BH3 family. We discuss apoptosis in ALL, the reliance mechanisms, drug development in this space, and areas for future research.

RECENT FINDINGS

The first drugs that were developed to inhibit the BCL-2 pathway include both venetoclax (BCL-2 specific inhibitor) and navitoclax (BCL-2, BCL-XL, and BCL-W). These drugs show promise and have obtained complete remissions, minimal residual disease negative status, and have been used as a bridge to allogeneic hematopoietic stem cell transplantation in acute myeloid leukemia and chronic lymphocytic leukemia. There are multiple ongoing clinical trials looking to assess the use of BCL-2 inhibition with chemotherapy, targeted therapies, and bi-specific T-cell engager therapies not only in both frontline and relapsed refractory ALL but also in consolidation and maintenance phases. There is still a large need for improvement of ALL outcomes in adult patients. Research has shown that ALL depends on the BCL-2 family of proteins for cell survival and proliferation. Targeting this pathway with BCL-2 inhibition has led to encouraging results, and future research is aimed at incorporating this targeted therapy into current treatment paradigms.

Allogeneic Hematopoietic Cell Transplantation for Adult Acute Lymphoblastic Leukemia in the Modern Era

Allogeneic hematopoietic cell transplantation (HCT) remains an important treatment for adults with acute lymphoblastic leukemia (ALL). We hypothesized that advances in ALL and transplantation have resulted in improved HCT outcomes in recent years. In this study, we evaluated the characteristics and outcomes of adult ALL patients undergoing allogeneic HCT over the last decade. Patients with ALL aged 18 years and older who underwent allogeneic HCT at Stanford University between 2008 and 2019 were included in this study. Patients were divided into 2 eras based on year of HCT: 2008 to 2013 (earlier era) and 2014 to 2019 (later era). A total of 285 patients were included: 119 patients underwent HCT in the earlier era and 166 in the later era. Patients who underwent transplantation in the later era were more likely to be Hispanic (38% versus 21%) and to have an HCT-comorbidity index ≥3 (31% versus 18%). Donor source for HCT also differed with an increase in the use of HLA-mismatched donor sources (38% versus 24%), notably umbilical cord blood in the later era (16% versus 0%). Patients in the later era were less likely to undergo transplantation with active disease (4% versus 16%); pre-HCT rates of measurable residual disease were similar across the eras (38% versus 40%). In unadjusted analyses, overall survival (OS) improved across eras, with 2-year estimates for the later and earlier eras of 73% (95% confidence interval [CI], 66%-80%) versus 55% (95% CI, 46%-64%), respectively. Multivariable analysis confirmed the association between later era and OS (hazard ratio = 0.52, 95% CI, 0.34-0.78). Finally, among patients relapsing after HCT (25% in later era and 33% in earlier era), the use of novel immunotherapies increased in the later era (44% versus 3%), as did the median OS after post-HCT relapse (16 months versus 8 months, P< .001). OS after HCT for adult ALL has improved in recent years. This is due, in part, to a significant improvement in the ability to effectively salvage adults with ALL relapsing after HCT.

DNA-thioguanine concentration and relapse risk in children and young adults with acute lymphoblastic leukemia: an IPD meta-analysis

Methotrexate/6-mercaptopurine maintenance therapy improves acute lymphoblastic leukemia (ALL) outcome. Cytotoxicity is mediated by DNA incorporation of thioguanine nucleotides (DNA-TG). We investigated the association of DNA-TG to relapse risk in 1 910 children and young adults with non-high risk ALL. In a cohort-stratified Cox regression analysis adjusted for sex, age, and white cell count at diagnosis, the relapse-specific hazard ratio (HRa) per 100 fmol/μg increase in weighted mean DNA-TG (wmDNA-TG) was 0.87 (95% CI 0.78-0.97; p = 0.013) in the 839 patients who were minimal residual disease (MRD) positive at end of induction therapy (EOI), whereas this was not the case in EOI MRD-negative patients (p = 0.76). Validation analysis excluding the previously published Nordic NOPHO ALL2008 pediatric cohort yielded a HRa of 0.92 (95% CI 0.82-1.03; p = 0.15) per 100 fmol/μg increase in wmDNA-TG in EOI MRD-positive patients. If also excluding the United Kingdom cohort, in which samples were taken non-randomly in selected patients, the HRa for the EOI MRD-positive patients was 0.82 (95% CI 0.68-0.99; p = 0.044) per 100 fmol/μg increase in wmDNA-TG. The importance of DNA-TG as a biomarker for maintenance therapy intensity calls for novel strategies to increase DNA-TG, although its clinical value may vary by protocol backbone.

How I Use Measurable Residual Disease in the Clinical Management of Adult Acute Lymphoblastic Leukemia

Over the last decade the use of measurable residual disease (MRD) diagnostics in adult acute lymphoblastic leukemia (ALL) has expanded from a limited number of study groups in Europe and the United States to a world-wide application. In this review, we summarize the advantages and drawbacks of the current available techniques used for MRD monitoring. Through the use of three representative case studies, we highlight the advances in the use of MRD in clinical decision-making in the management of ALL in adults. We acknowledge discrepancies in MRD monitoring and treatment between different countries, reflecting differing availability, accessibility and affordability.

Role of matrix metalloproteinase MMP-2, MMP-9 and tissue inhibitor of metalloproteinase (TIMP-1) in the clinical progression of pediatric acute lymphoblastic leukemia

BACKGROUND

Matrix metalloproteinases (MMPs) play a crucial role in cancer progression and metastasis, however their role in pediatric Acute lymphoblastic leukemia (ALL) is still unrevealed.

METHODS

The diagnostic, prognostic and predictive value of tissue inhibitor of metalloproteinase (TIMP-1), MMP-2, MMP-9 and CD34+CD38- cancer stem cells (CSCs) were assessed in bone marrow (BM) samples of 76 ALL children using Flow Cytometry analysis.

RESULTS

There was a significant increase in TIMP-1 [1.52 (0.41-10) versus 0.91(0.6-1.12); respectively, p < 0.001], and CSCs CD34⁺CD38^- [1 (0.03-18.6) versus 0.3 (0.01-1.1), p < 0.001] expression in ALL patients compared to controls. While there were no significant differences regarding MMP-2 and MMP-9 expression between the two groups. The sensitivity, specificity, area under curve (AUC) of MMP-2 were (80.3%, 53.3% and 0.568, p = 0.404), and of MMP-9 were (53.9%, 40% and 0.660, p = 0.053). While that of TIMP-1 were (78.9%, 100% and 0.892, p < 0.001), and that of CD34⁺CD38^- CSCs were (78.9%, 73.3% and 0.855, p < 0.001). Increased TIMP-1 expression associated with the high-risk disease (p < 0.001). CD34⁺CD38^- CSCs and MMP-2 overexpression associated with MRD at day-15, increased BM blast cell count at diagnosis and at day-15 (p < 0.05). TIMP-1 overexpression is associated with shorter DFS and OS rates (p = 0.009 and p = 0.048). Multivariate logistic regression analysis showed that both TIMP-1 [OR: 4.224, p = 0.046], and CD34⁺CD38^- CSCs [OR: 6.873, p = 0.005] could be potential independent diagnostic factors for pediatric ALL.

CONCLUSION

TIMP-1 and CD34⁺CD38^- CSCs could be possible useful diagnostic markers for pediatric ALL. Also, TIMP-1 is a promising prognostic marker for poor outcome of the patients.

Hematological characteristics, cytogenetic features, and post-induction measurable residual disease in thymic stromal lymphopoietin receptor (TSLPR) overexpressed B-cell acute lymphoblastic leukemia in an Indian cohort

The overexpression of cytokine receptor-like factor-2 (CRLF2) identified by anti-thymic stromal lymphopoietin receptor/TSLPR flow cytometry (FCM) has been reported as a screening tool for the identification of BCR-ABL1-like B-cell acute lymphoblastic leukemia/B-ALL with CRLF2 re-arrangement. TSLPR expression was studied prospectively in consecutive 478 B-ALLs (≤ 12 years (n = 244); 13-25 years (n = 129); > 25 years (n = 105)) and correlated with various hematological parameters and end-of-induction measurable residual disease (day 29; MRD ≥ 0.01% by 10-color FCM). TSLPR positivity in ≥ 10% leukemic cells was detected in 14.6% (n = 70) of B-ALLs. CRLF2 re-arrangement was detected in eight cases (11.4%) including P2RY8-CRLF2 (n = 6), and IgH-CRLF2 (n = 2) with a median TSLPR positivity of 48.8% and 99% leukemic cells, respectively. Recurrent gene fusions/RGF (BCR-ABL1 (17.1%); ETV6-RUNX1 (4.2%), TCF3-PBX1 (1.4%)), other BCR-ABL1-like chimeric gene fusions/CGFs (PDGFRB-rearrangement (2.9%), IgH-EPOR (1.4%)), CRLF2 extra-copies/hyperdiploidy (17.1%), and IgH translocation without a known partner (10%) were also detected in TSLPR-positive patients. CD20 positivity (52.9% vs 38.5%; p = 0.02) as well as iAMP21 (4.3% vs 0.5%; p = 0.004) was significantly more frequent in TSLPR-positive cases. TSLPR-positive patients did not show a significantly higher MRD, compared to TSLPR-negative cases (37% vs 33%). Increasing the threshold cut-off (from ≥ 10 to > 50% or > 74%) increased the specificity to 88% and 100% respectively in identifying CRLF2 translocation. TSLPR expression is not exclusive for CRLF2 translocations and can be seen with various other RGFs, necessitating their testing before its application in diagnostic algorithms. In patients with high TSLPR positivity (> 50%), the testing may be restricted to CRLF2 aberrancies, while patients with 10-50% TSLPR positivity need to be tested for both CRLF2- and non-CRLF2 BCR-ABL1-like CGFs.

Inotuzumab Ozogamicin for Relapsed/Refractory Acute Lymphoblastic Leukemia in the INO-VATE Trial: CD22 Pharmacodynamics, Efficacy, and Safety by Baseline CD22

PURPOSE

We assessed the relationship between cluster of differentiation-22 (CD22) expression and outcomes of inotuzumab ozogamicin versus standard of care (SC) in INO-VATE (NCT01564784).

PATIENTS AND METHODS

Adults with relapsed/refractory B-cell precursor CD22-positive (by local or central laboratory) acute lymphoblastic leukemia were randomized to inotuzumab ozogamicin (n = 164) or SC (n = 162). Outcomes were analyzed by baseline CD22 positivity (percentage of leukemic blasts CD22 positive, ≥90% vs. <90%) and CD22 receptor density [molecules of equivalent soluble fluorochrome (MESF), quartile analysis].

RESULTS

Most patients had high (≥90%) CD22 positivity per central laboratory. The response rate was significantly higher with inotuzumab ozogamicin versus SC. Minimal/measurable residual disease negativity, duration of remission (DoR), progression-free survival, and overall survival (OS) were significantly better with inotuzumab ozogamicin versus SC in patients with CD22 positivity ≥90%. Fewer patients had CD22 positivity <90%; for whom, response rates were higher with inotuzumab ozogamicin versus SC, but DoR and OS appeared similar. Similar trends were evident in quartile analyses of CD22 MESF and CD22 positivity per local laboratory. Among inotuzumab ozogamicin-responding patients with subsequent relapse, decrease in CD22 positivity and receptor density was evident, but not the emergence of CD22 negativity. Rates of grade ≥3 hematologic adverse events (AEs) were similar and hepatobiliary AEs rate was higher for inotuzumab ozogamicin versus SC. No apparent relationship was observed between the rates of hematologic and hepatic AEs and CD22 expression.

CONCLUSIONS

Inotuzumab ozogamicin demonstrated a favorable benefit-risk profile versus SC in patients with higher and lower CD22 expression. Patients with high CD22 expression and normal cytogenetics benefited the most from inotuzumab ozogamicin therapy.

Diagnostic, prognostic and predictive values of miR-100 and miR-210 in pediatric acute lymphoblastic Leukemia

BACKGROUND

: microRNAs are playing important roles in the diagnosis and prognosis of pediatric acute lymphoblastic leukemia (ALL).

METHODS

Expression levels of miR-100 and miR-210 were assessed in bone marrow aspirate of 85 pediatric ALL patients compared to 12 healthy control using quantitative real-time polymerase chain reaction. Data were correlated with relevant clinico-pathological features of the patients, response to treatment, disease-free survival (DFS), and overall survival (OS).

RESULTS

miR-100 was significantly downregulated in ALL patients [median: 1.21, range: 0-434.3] compared to the control group [median: 8.41, range; 0-840.3, P = 0.035]. miR-210 was significantly upregulated in ALL patients [median: 6.34, range: 1.16-1088.7] compared to the control group [median: 2.57, range: 0.11-709.2, P  = 0.025]. The sensitivity, specificity, and area under curve of miR-100 were (64.7%, 62.5%, and 0.642; respectively, P = 0.035) at a cut-off 2.6 and that of miR-210 were (60%, 58.3% and 0.650; respectively, P = 0.025) at a cut-off 3.5. miR-100 overexpression associated with shorter DFS and OS (P = 0.033 and 0.046; respectively). Patients with miR-100 lowexpression showed a significant incidence of late death ( P = 0.024). There was no significant association between miR-210 expression and DFS, OS, incidence of early or late death.

CONCLUSION

: miR-100 and miR-210 could be used as potential diagnostic markers for pediatric ALL. miR-100 is a useful prognostic and predictive biomarker for childhood ALL.

A Systematic Review of Blinatumomab in the Treatment of Acute Lymphoblastic Leukemia: Engaging an Old Problem With New Solutions

OBJECTIVE

To assess the current literature for blinatumomab in the treatment of adult and pediatric B-cell acute lymphoblastic leukemia (ALL).

DATA SOURCES

We conducted a PubMed (inception to December 11, 2020) and ClinicalTrials.gov systematic literature search using the following terms: blinatumomab, Blincyto, lymphoblastic leukemia, and bispecific T-cell engager.

STUDY SELECTION AND DATA EXTRACTION

All relevant published articles, package inserts, and meeting abstracts evaluating the use of blinatumomab in ALL were considered for inclusion.

DATA SYNTHESIS

Blinatumomab, a first-in-class bispecific T-cell engager monoclonal antibody, facilitates cytotoxic T-cell activation and subsequent eradication of CD19-positive B cells. The confirmatory phase III TOWER trial demonstrated superior overall survival (OS) with blinatumomab compared with standard chemotherapy (7.7 months vs 4.0 months) in relapsed and refractory (R/R) B-cell ALL. In the phase II BLAST trial, blinatumomab achieved a complete measurable residual disease (MRD) response in 78% of evaluable patients, with a median OS of 36.5 months. Potentially life-threatening cytokine release syndrome and neurotoxicity occurred in approximately 15% and 65% of patients, respectively.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

Following initial Food and Drug Administration approval in 2014, blinatumomab gained expanded approval in pediatric patients and in Philadelphia chromosome-positive R/R ALL. In 2018, blinatumomab became the first and only drug approved for the treatment of persistent MRD in any hematologic malignancy. Emerging data demonstrate promising efficacy with blinatumomab in specific ALL settings, including frontline therapy, as a bridge to transplantation, and in "chemotherapy-free" combination regimens.

CONCLUSIONS

Blinatumomab provides a paradigm-shifting treatment option; however, many questions surrounding optimal patient selection, sequencing, and cost-effectiveness remain.

High-throughput sequencing of immunoglobulin heavy chain for minimal residual disease detection in B-lymphoblastic leukemia

INTRODUCTION

Minimal residual disease (MRD) is a cornerstone for stratification of upfront B-lymphoblastic leukemia (B-ALL) treatment protocols to decrease relapse risk. Although its detection by flow cytometry (FC) and real-time quantitative polymerase has clinical usefulness, evidence suggests that methods with increased sensitivity could lead to improved outcomes. The aim of this study was to develop an amplicon-based assay followed by high-throughput sequencing of the immunoglobulin heavy chain variable region for MRD detection in B-ALL.

METHODS

We analyzed 84 samples, 27 from diagnosis, 5 from relapse, 40 from post-treatment samples, and 12 from healthy controls.

RESULTS

Our assay was able to identify more neoplastic clones at diagnosis than Sanger sequencing including incomplete DJ rearrangements. From the 40 MRD samples evaluated 21 were positive by our new approach on high-throughput sequencing assay, but only 15 of these were positive by FC. The remaining 19 were negative by the two techniques.

CONCLUSION

We have developed a novel approach on high-sensitive assay for MRD detection in B-ALL, which could add clinical value in the management of patients, especially in cases negative for MRD by FC.

Recent Advances in Molecular Diagnosis and Prognosis of Childhood B Cell Lineage Acute Lymphoblastic Leukemia (B-ALL)

B cell lineage acute lymphoblastic leukemia is the most common leukemia occurring in children and young adults and is the leading cause of cancer related deaths. The 5 year overall survival outcome in children with B-ALL has improved significantly in the last few decades. In the past, the discovery of various genetic alterations and targeted therapy have played a major role in decreasing disease-related deaths. In addition, numerous advances in the pathogenesis of B-ALL have been found which have provided better understanding of the genes involved in disease biology with respect to diagnostic and prognostic implications. Present review will summarize current understanding of risk stratification, genetic factors including cytogenetics in diagnosis and prognosis of B-ALL.

Prognostic factors for survival after allogeneic transplantation in acute lymphoblastic leukemia

Allogeneic stem cell transplantation (allo-SCT) offers a curative option in adult patients with acute lymphoblastic leukemia (ALL). Prognostic factors for survival after allo-SCT have not been sufficiently defined: pheno-/genotype, patients´ age, conditioning regimens and remission at allo-SCT are under discussion. We analyzed the outcome of 180 consecutive adult ALL-patients undergoing allo-SCT at our center between 1995 and 2018 to identify specific prognostic factors. In our cohort 19% were older than 55 years, 28% had Philadelphia-positive B-ALL, 24% T-ALL. 54% were transplanted in first complete remission (CR1), 13% in CR2 after salvage therapy, 31% reached no remission (8% within first-line, 23% within salvage therapy). In 66% conditioning contained total body irradiation (TBI). With a median follow-up of 10 years, we observed an overall survival of 33% at 10 years, and a progression free survival of 31%. The cumulative incidence of relapse was 41% at 10 years, the cumulative incidence of non-relapse mortality 28%. Acute graft-versus-host disease (GvHD) II°-IV° occurred in 31%, moderate/severe chronic GvHD in 27%. Survival was better in patients reaching CR before allo-SCT and in those receiving TBI. No difference between patients younger/older than 55 years and between different phenotypes was observed. Survival after allo-SCT improved considerably over the last decades.

Microfluidic Chip based direct triple antibody immunoassay for monitoring patient comparative response to leukemia treatment

We report a time and cost-efficient microfluidic chip for screening the leukemia cells having three specific antigens. In this method, the target blast cells are double sorted with immunomagnetic beads and captured by the 3rd antibody immobilized on the gold surface in a microfluidic chip. The captured blast cells in the chip were imaged using a bright-field optical microscope and images were analyzed to quantify the cells. First sorting was performed with nano size immunomagnetic beads and followed by 2nd sorting where micron size immunomagnetic beads were used. The low-cost microfluidic platform is made of PMMA and glass including micro size gold pads. The developed microfluidic platform was optimized with cultured B type lymphoblast cells and tested with the samples of leukemia patients. The 8 bone marrow samples of 4 leukemia patients on the initial diagnosis and on the 15th day after the start of the chemotherapy treatment were tested both with the developed microfluidic platform and the flow cytometry. A 99% statistical agreement between the two methods shows that the microfluidic chip is able to monitor the decrease in the number of blast cells due to the chemotherapy. The experiments with the patient samples demonstrate that the developed system can perform relative measurements and have a potential to monitor the patient response to the applied therapy and to enable personalized dose adjustment.

Integrative genomic analyses reveal mechanisms of glucocorticoid resistance in acute lymphoblastic leukemia

Identification of genomic and epigenomic determinants of drug resistance provides important insights for improving cancer treatment. Using agnostic genome-wide interrogation of mRNA and miRNA expression, DNA methylation, SNPs, CNAs and SNVs/Indels in primary human acute lymphoblastic leukemia cells, we identified 463 genomic features associated with glucocorticoid resistance. Gene-level aggregation identified 118 overlapping genes, 15 of which were confirmed by genome-wide CRISPR screen. Collectively, this identified 30 of 38 (79%) known glucocorticoid-resistance genes/miRNAs and all 38 known resistance pathways, while revealing 14 genes not previously associated with glucocorticoid-resistance. Single cell RNAseq and network-based transcriptomic modelling corroborated the top previously undiscovered gene, CELSR2. Manipulation of CELSR2 recapitulated glucocorticoid resistance in human leukemia cell lines and revealed a synergistic drug combination (prednisolone and venetoclax) that mitigated resistance in mouse xenograft models. These findings illustrate the power of an integrative genomic strategy for elucidating genes and pathways conferring drug resistance in cancer cells.

Characterizing Deformability of Drug Resistant Patient-Derived Acute Lymphoblastic Leukemia (ALL) Cells Using Acoustic Tweezers

The role of cell mechanics in cancer cells is a novel research area that has resulted in the identification of new mechanisms of therapy resistance. Single beam acoustic (SBA) tweezers are a promising technology for the quantification of the mechanical phenotype of cells. Our previous study showed that SBA tweezers can be used to quantify the deformability of adherent breast cancer cell lines. The physical properties of patient-derived (primary) pre-B acute lymphoblastic leukemia (ALL) cells involved in chemotherapeutic resistance have not been widely investigated. Here, we demonstrate the feasibility of analyzing primary pre-B ALL cells from four cases using SBA tweezers. ALL cells showed increased deformability with increasing acoustic pressure of the SBA tweezers. Moreover, ALL cells that are resistant to chemotherapeutic drugs were more deformable than were untreated ALL cells. We demonstrated that SBA tweezers can quantify the deformability of nonadherent leukemia cells and discriminate this mechanical phenotype in chemotherapy-resistant leukemia cells in a contact- and label-free manner.

Synergistic action of dual IGF1/R and MEK inhibition sensitizes childhood acute lymphoblastic leukemia (ALL) cells to cytotoxic agents and involves downregulation of STAT6 and PDAP1

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Dual insulin-like growth factor 1 receptor (IGF1/R) + mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEK) inhibition synergistically sensitize apoptosis-resistant acute lymphoblastic leukemia (ALL) cells.

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Dual IGF1/R + MEK inhibition potentiates chemotherapy-induced killing of ALL cells.

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Signal transducer and activator of transcription 6 (STAT6) and platelet-derived growth factor-associated protein 1 (PDAP1) are downregulated differentially by this synergistic action.

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STAT6 and PDAP1 are predicted to act in a putative STAT6–ERK–nuclear factor kappa beta (NF-κB) survival network.

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Targeting this network may be useful for sensitizing ALL to chemotherapy agents.

Heterogeneous upregulation of multiple prosurvival pathways underlies resistance to damage-induced apoptosis in acute lymphoblastic leukemia (ALL) cells despite normal p53 responses. Here, we show that the dual combination of insulin-like growth factor 1 (IGF1)/IGF1 receptor (IGF1/R) and mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEK) inhibition using AG1024 + U0126 can sensitize apoptosis-resistant ALL cells to ionizing radiation-induced DNA damage irrespective of effect of single pathway inhibition in vitro. This AG1024 + U0126 combination also significantly potentiates the ability of the core chemotherapy compounds vincristine, dexamethasone, and daunorubicin to kill ALL cells in vitro. Evidence of the synergistic action of AG1024 + U0126 in samples with variable basal levels of phosphorylated IGF1/Rβ and ERK1/2 suggested additional targets of this drug combination. Consistent with this, gene expression profiling identified 32 “synergy genes” differentially targeted by IGF1/R + MEK inhibition and, among these, Signal transducer and activator of transcription 6 (STAT6) and platelet-derived growth factor-associated protein 1 (PDAP1) were the most differentially downregulated cluster. Pearson correlation analysesrevealed that STAT6 and PDAP1 display significant expression codependency and a common expression pattern linked with other key “synergy” genes, supporting their predicted role in an STAT6–ERK–nuclear factor kappa beta (NF-κB) network. Knockdown studies revealed that loss of STAT6, but not PDAP1, impinges on the cell cycle, causing reduced numbers of viable cells. In combination with daunorubicin, STAT6 loss has an additive effect on cell killing, whereas PDAP1 loss is synergistic, indicating an important role of PDAP1 in the cellular response to this anthracycline. Inhibition of STAT6 or PDAP1 may therefore represent a potential novel therapeutic strategy for resistant ALL by enhancing sensitivity to chemotherapy.

The lncRNA CASC15 regulates SOX4 expression in RUNX1-rearranged acute leukemia

BACKGROUND

Long non-coding RNAs (lncRNAs) play a variety of cellular roles, including regulation of transcription and translation, leading to alterations in gene expression. Some lncRNAs modulate the expression of chromosomally adjacent genes. Here, we assess the roles of the lncRNA CASC15 in regulation of a chromosomally nearby gene, SOX4, and its function in RUNX1/AML translocated leukemia.

RESULTS

CASC15 is a conserved lncRNA that was upregulated in pediatric B-acute lymphoblastic leukemia (B-ALL) with t (12; 21) as well as pediatric acute myeloid leukemia (AML) with t (8; 21), both of which are associated with relatively better prognosis. Enforced expression of CASC15 led to a myeloid bias in development, and overall, decreased engraftment and colony formation. At the cellular level, CASC15 regulated cellular survival, proliferation, and the expression of its chromosomally adjacent gene, SOX4. Differentially regulated genes following CASC15 knockdown were enriched for predicted transcriptional targets of the Yin and Yang-1 (YY1) transcription factor. Interestingly, we found that CASC15 enhances YY1-mediated regulation of the SOX4 promoter.

CONCLUSIONS

Our findings represent the first characterization of this CASC15 in RUNX1-translocated leukemia, and point towards a mechanistic basis for its action.

Acute lymphoblastic leukemia: a comprehensive review and 2017 update

Acute lymphoblastic leukemia (ALL) is the second most common acute leukemia in adults, with an incidence of over 6500 cases per year in the United States alone. The hallmark of ALL is chromosomal abnormalities and genetic alterations involved in differentiation and proliferation of lymphoid precursor cells. In adults, 75% of cases develop from precursors of the B-cell lineage, with the remainder of cases consisting of malignant T-cell precursors. Traditionally, risk stratification has been based on clinical factors such age, white blood cell count and response to chemotherapy; however, the identification of recurrent genetic alterations has helped refine individual prognosis and guide management. Despite advances in management, the backbone of therapy remains multi-agent chemotherapy with vincristine, corticosteroids and an anthracycline with allogeneic stem cell transplantation for eligible candidates. Elderly patients are often unable to tolerate such regimens and carry a particularly poor prognosis. Here, we review the major recent advances in the treatment of ALL.

Minimal Residual Disease and Childhood Leukemia: Standard of Care Recommendations From the Pediatric Oncology Group of Ontario MRD Working Group

Minimal residual disease (MRD) is an independent predictor of relapse risk in children with leukemia and is widely used for risk-adapted treatment. This article summarizes current evidence supporting the use of MRD, including clinical significance, current international clinical practice, impact statement, and recommended indications. The proposed MRD recommendations have been endorsed by the MRD Working Group of the Pediatric Oncology Group of Ontario and provide the foundation for a strategy that aims at equitable access to MRD evaluation for children with leukemia.

Proposal for the standardization of flow cytometry protocols to detect minimal residual disease in acute lymphoblastic leukemia

Minimal residual disease is the most powerful predictor of outcome in acute leukemia and is useful in therapeutic stratification for acute lymphoblastic leukemia protocols. Nowadays, the most reliable methods for studying minimal residual disease in acute lymphoblastic leukemia are multiparametric flow cytometry and polymerase chain reaction. Both provide similar results at a minimal residual disease level of 0.01% of normal cells, that is, detection of one leukemic cell in up to 10,000 normal nucleated cells. Currently, therapeutic protocols establish the minimal residual disease threshold value at the most informative time points according to the appropriate methodology employed. The expertise of the laboratory in a cancer center or a cooperative group could be the most important factor in determining which method should be used. In Brazil, multiparametric flow cytometry laboratories are available in most leukemia treatment centers, but multiparametric flow cytometry processes must be standardized for minimal residual disease investigations in order to offer reliable and reproducible results that ensure quality in the clinical application of the method. The Minimal Residual Disease Working Group of the Brazilian Society of Bone Marrow Transplantation (SBTMO) was created with that aim. This paper presents recommendations for the detection of minimal residual disease in acute lymphoblastic leukemia based on the literature and expertise of the laboratories who participated in this consensus, including pre-analytical and analytical methods. This paper also recommends that both multiparametric flow cytometry and polymerase chain reaction are complementary methods, and so more laboratories with expertise in immunoglobulin/T cell receptor (Ig/TCR) gene assays are necessary in Brazil.

Leukemias in Children

Childhood cancers are rare but an important cause of morbidity and mortality in children younger than 15 y of age. Common childhood malignancies include leukemias (commonest, 30-40%), brain tumors (20%) and lymphoma (12%) followed by neuroblastoma, retinoblastoma and tumors arising from soft tissues, bones and gonads. Leukemias, the commonest childhood cancer, arise from clonal proliferation of abnormal hematopoietic cells leading to disruption of normal marrow function and marrow failure. The various clinical manifestations of leukemia result from unregulated proliferation of the malignant clone and bone marrow failure. There are two main subtypes, the commoner, acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). A small proportion may have chronic myeloid leukemia (CML) and juvenile myelomonocytic leukemia (JMML). A systematic approach is necessary for diagnosis. Treatment should be initiated as early as possible to avoid complications. A timely referral to a cancer center must be done if facilities for diagnosis/treatment, management of complications and provision for supportive care are not available at the treating center.

Leukemias in Children

Childhood cancers are rare but an important cause of morbidity and mortality in children younger than 15 y of age. Common childhood malignancies include leukemias (commonest, 30-40%), brain tumors (20%) and lymphoma (12%) followed by neuroblastoma, retinoblastoma and tumors arising from soft tissues, bones and gonads. Leukemias, the commonest childhood cancer, arise from clonal proliferation of abnormal hematopoietic cells leading to disruption of normal marrow function and marrow failure. The various clinical manifestations of leukemia result from unregulated proliferation of the malignant clone and bone marrow failure. There are two main subtypes, the commoner, acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). A small proportion may have chronic myeloid leukemia (CML) and juvenile myelomonocytic leukemia (JMML). A systematic approach is necessary for diagnosis. Treatment should be initiated as early as possible to avoid complications. A timely referral to a cancer center must be done if facilities for diagnosis/treatment, management of complications and provision for supportive care are not available at the treating center.

Quantitative detection of the human cervical cancer oncogene for monitoring the minimal residual disease in acute leukemia

The human cervical cancer oncogene (HCCR) has been shown to be over-expressed in some solid tumors, and its function is involved in negative regulation of p53 tumor suppressor gene. However, the roles of HCCR in leukemia remain unclear. The present study is to investigate whether the expression levels of HCCR mRNA are associated with clinical prognosis in patients with acute leukemia (AL) and to explore the potential use as a biomarker for monitoring minimal residual disease (MRD) in AL. The mRNA levels of HCCR1 and HCCR2 were quantified by real-time reverse transcription polymerase chain reaction in bone marrow samples from 80 adult de novo AL patients and 20 normal healthy donors. The expressions of HCCR1 and HCCR2 were significantly higher in patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) than those in healthy donors (P < 0.01), but there was no significant difference between AML and ALL (P > 0.05). Besides white blood cell count, we did not find any significant correlation between HCCR expression and clinical characteristics, such as age, sex, CD34 antigen expression, and response to chemotherapy. HCCR was monitored in 12 cases during remission and/or relapse. Significant reductions of both HCCR1 and HCCR2 mRNA levels were observed in patients who had achieved complete remission after chemotherapy but not in patients with non-responsive. However, an increased HCCR expression was detected in these patients who relapsed. Our findings suggest that HCCR gene is over-expressed in AL patients and may be as a useful biomarker for monitoring MRD in AL.

Peripheral blood 8 colour flow cytometry monitoring of hairy cell leukaemia allows detection of high-risk patients

Although purine analogues have significantly improved the outcome of hairy cell leukaemia (HCL) patients, 30-40% relapse, illustrating the need for minimal residual disease (MRD) markers that can aid personalized therapeutic management. Diagnostic samples from 34 HCL patients were used to design an 8-colour flow cytometry (8-FC) tube for blood MRD (B/RD) analysis (188 samples) which was compared to quantitative IGH polymerase chain reaction (Q-PCR) on 83 samples and to qualitative consensus IGH PCR clonality analysis on 165 samples. Despite heterogeneous HCL phenotypes at diagnosis, discrimination from normal B lymphocytes was possible in all cases using a single 8-FC tube, with a robust sensitivity of detection of 10(-4) , comparable to Q-PCR at this level, but preferable in terms of informativeness, simplicity and cost. B/RD assessment of 15 patients achieving haematological complete remission after purine analogues was predictive of a clinically significant relapse risk: with a median follow-up of 95 months; only one of the nine patients with reproducible 8-FC B/RD levels below 10(-4) (B/RD(neg) ) relapsed, compared to 5/6 in the B/RD(pos) group (P = 0.003). These data demonstrate the clinical interest of a robust 8-FC HCL B/RD strategy that could become a surrogate biomarker for therapeutic stratification and new drug assessment, which should be evaluated prospectively.

Immunophenotypic, Cytogenetic and Clinical Features in Chinese Adult Acute Lymphoblastic Leukaemia (ALL) Patients

Introduction: This study sought to investigate the immunophenotypic subtype profiles of 110 Chinese adult patients with acute lymphoblastic leukaemia (ALL) and its association to cytogenetics and the clinical features. Materials and Methods: A total of 110 adult patients with ALL were immunophenotyped by CD45/SSC double parameters and 4 colour flow cytometry. Seventy-three cases were also subjected to karyotype analysis by R-banding technology. The clinical and laboratory data of 110 ALL patients were retrospectively analysed. Results: Of all the patients, 21.8% were identified as T-ALL, 78.2% as B-ALL. Abnormal karyotypes were detected in 37 out of 73 (50.7%) cases and the most common cytogenetic abnormality was the Philadelphia (Ph) chromosome, which was found in 23.3% (17/73) of the cases. Myeloid antigen (MyAg) expression was documented in 47.3% of the 110 adult ALL cases analysed and CD13 was the most commonly expressed MyAg in ALL patients (32.1 %). No difference was observed in the expression of MyAg between the groups of patients with T-ALL (45.8%) and B-ALL (47.7%). Our data showed that older age, higher CD34 positivity and lower proportion of patients with splenomegaly were found to be correlated with MyAg+ ALL, and that patients with Ph+ B-ALL were older, presented with higher haemoglobin level and higher CD34 expression. No statistical difference was noted in complete remission (CR) rate, relapse rate, induction mortality or total death rate among My+ and My-, Ph+ and Ph-, or B-ALL and T-ALL patients. Conclusion: Our results indicate that the distribution of ALL in Chinese adult patients was similar with the general distribution pattern in the other countries, and the expression of MyAg in patients with T-ALL and B-ALL was comparable. Both the expression of MyAg and the presence of Ph chromosome in adult ALL were significantly associated with median age and CD34 expression while not with the response to induction treatment. Key words: Biological characteristics, Cytogenetics, Immunophenotype

Flow cytometry in hematological disorders

Flow cytometry with its rapidly increasing applications is being used essentially in all fields of diagnostic medicine. In hematological disorders it is most commonly used in diagnosis, characterization, prognostication and even selecting target therapy of acute leukemia and to some extent lymphomas. It is increasingly finding place in other fields of hematology i.e., non-malignant disorders of all blood cell types including RBCs and platelets along with leukocytes. In this review the authors have discussed some of these applications with an emphasis on disorders specific to pediatric patients.

BET inhibition as a single or combined therapeutic approach in primary paediatric B-precursor acute lymphoblastic leukaemia

Paediatric B-precursor ALL is a highly curable disease, however, treatment resistance in some patients and the long-term toxic effects of current therapies pose the need for more targeted therapeutic approaches. We addressed the cytotoxic effect of JQ1, a highly selective inhibitor against the transcriptional regulators, bromodomain and extra-terminal (BET) family of proteins, in paediatric ALL. We showed a potent in vitro cytotoxic response of a panel of primary ALL to JQ1, independent of their prognostic features but dependent on high MYC expression and coupled with transcriptional downregulation of multiple pro-survival pathways. In agreement with earlier studies, JQ1 induced cell cycle arrest. Here we show that BET inhibition also reduced c-Myc protein stability and suppressed progression of DNA replication forks in ALL cells. Consistent with c-Myc depletion and downregulation of pro-survival pathways JQ1 sensitised primary ALL samples to the classic ALL therapeutic agent dexamethasone. Finally, we demonstrated that JQ1 reduces ALL growth in ALL xenograft models, both as a single agent and in combination with dexamethasone. We conclude that targeting BET proteins should be considered as a new therapeutic strategy for the treatment of paediatric ALL and particularly those cases that exhibit suboptimal responses to standard treatment.

Developments in the immunophenotypic analysis of haematological malignancies

Immunophenotyping is the method by which antibodies are used to detect cellular antigens in clinical samples. Although the major role is in the diagnosis and classification of haematological malignancies, applications have expanded over the past decade. Immunophenotyping is now used extensively for disease staging and monitoring, to detect surrogate markers of genetic aberrations, to identify potential immuno-therapeutic targets and to aid prognostic prediction. This expansion in applications has resulted from developments in antibodies, methodology, automation and data handling. In this review we describe recent advances in both the technology and applications for the analysis of haematological malignancies. We highlight the importance of the expanding repertoire of testing capability for diagnostic, prognostic and therapeutic applications. The impact and significance of immunophenotyping in the assessment of haematological neoplasms are evident.

Genome-wide association study identifies germline polymorphisms associated with relapse of childhood acute lymphoblastic leukemia

With the use of risk-directed therapy for childhood acute lymphoblastic leukemia (ALL), outcome has improved dramatically in the past 40 years. However, a substantial portion of patients, many of whom have no known risk factors, experience relapse. Taking a genome-wide approach, in the present study, we evaluated the relationships between genotypes at 444 044 single nucleotide polymorphisms (SNPs) with the risk of relapse in 2535 children with newly diagnosed ALL after adjusting for genetic ancestry and treatment regimen. We identified 134 SNPs that were reproducibly associated with ALL relapse. Of 134 relapse SNPs, 133 remained prognostic after adjusting for all known relapse risk factors, including minimal residual disease, and 111 were significant even among patients who were negative for minimal residual disease after remission induction therapy. The C allele at rs7142143 in the PYGL gene was associated with 3.6-fold higher risk of relapse than the T allele (P = 6.7 × 10(-9)). Fourteen of the 134 relapse SNPs, including variants in PDE4B and ABCB1, were also associated with antileukemic drug pharmacokinetics and/or pharmacodynamics. In the present study, we systematically identified host genetic variations related to treatment outcome of childhood ALL, most of which were prognostic independent of known risk factors for relapse, and some of which also influenced outcome by affecting host dis-position of antileukemic drugs. All trials are registered at www.clinicaltrials.gov or www.cancer.gov (COG P9904: NCT00005585; COG P9905: NCT00005596; COG P9906: NCT00005603; St Jude Total XIIIB: NCI-T93-0101D; and St Jude Total XV: NCT00137111).

Molecular biology strategies to detect residual disease

The prognostic significance of minimal residual disease (MRD) has been demonstrated for a variety of hematologic malignancies. PCR based assays are among the most important methods for identifying MRD. They are aimed at detecting genetic abnormalities of residual leukemic cells with high specificity and sensitivity and represent an important diagnostic tool to assess the quality of therapeutic response, for clinical risk assessment, and for clinical management. In the present review technical aspects of different MRD detection methods are discussed which depend on the available targets regularly present in the respective leukemia type and subtype. As such fusion transcripts, gene mutations, and clonal rearrangements of antigen-receptor genes may be available for detection. Emphasis is given on discussing benefits and limitations of MRD detection and quantification in CML, AML and ALL.

A new method for high speed, sensitive detection of minimal residual disease

Investigations of rare cell types in peripheral blood samples, such as tumor, fetal, and endothelial cells, represent an emerging field with several potentially valuable medical applications. Peripheral blood is a particularly attractive body fluid for the detection of rare cells as its collection is minimally invasive and can be repeated throughout the course of the disease. Because the number of rare cells in mononuclear cells can be very low (1 in 10 million), a large number of cells must be quickly screened, which places demanding requirements on the screening technology. While enrichment technology has shown promise in managing metastatic disease, enrichment can cause distortions of cell morphology that limit pathological identification, and the enrichment targeting adds additional constraints that can affect sensitivity. Here, we describe a new approach for detecting rare leukemia cells that does not require prior enrichment. We have developed an immunocytochemical assay for identification of leukemia cells spiked in peripheral blood samples, and a high-speed scanning instrument with high numerical aperture and wide field of view to efficiently locate these cells in large sample sizes. A multiplex immunoassay with four biomarkers was used to uniquely identify the rare cells from leukocytes and labeling artifacts. The cytometer preserves the cell morphology and accurately locates labeled rare cells for subsequent high resolution imaging. The sensitivity and specificity of the approach show promise for detection of a low number of leukemia cells in blood (1 in 10 million nucleated cells). The method enables rapid location of rare circulating cells (25 M cells/min), no specific enrichment step, and excellent imaging of cellular morphology with multiple immunofluorescent markers. The cell imaging is comparable to other imaging approaches such as laser scan cytometry and image flow cytometry, but the cell analysis rate is many orders of magnitude faster making this approach practical for detection of rare cells.

CASP8AP2 is a promising prognostic indicator in pediatric acute lymphoblastic leukemia

The prognostic significance of caspase 8 associated protein 2 (CASP8AP2) in pediatric ALL is controversial. We determined a cut-off of CASP8AP2 expression in bone marrow samples of 39 newly diagnosed patients, and found a significantly poor bone marrow relapse-free survival (p=0.019) in low-expression group and verified it in another cohort of 106 patients (p=0.002). Furthermore, as an independent prognostic factor, CASP8AP2 expression was correlated to minimal residual disease (MRD), and incorporating it with MRD would help to identify patients at greater risk of bone marrow relapse. We also developed an algorithm comprised of clinical risk and CASP8AP2 expression, which could predict bone marrow relapse more accurately.

Targeted therapy with the T-cell-engaging antibody blinatumomab of chemotherapy-refractory minimal residual disease in B-lineage acute lymphoblastic leukemia patients results in high response rate and prolonged leukemia-free survival

PURPOSE

Blinatumomab, a bispecific single-chain antibody targeting the CD19 antigen, is a member of a novel class of antibodies that redirect T cells for selective lysis of tumor cells. In acute lymphoblastic leukemia (ALL), persistence or relapse of minimal residual disease (MRD) after chemotherapy indicates resistance to chemotherapy and results in hematologic relapse. A phase II clinical study was conducted to determine the efficacy of blinatumomab in MRD-positive B-lineage ALL.

PATIENTS AND METHODS

Patients with MRD persistence or relapse after induction and consolidation therapy were included. MRD was assessed by quantitative reverse transcriptase polymerase chain reaction for either rearrangements of immunoglobulin or T-cell receptor genes, or specific genetic aberrations. Blinatumomab was administered as a 4-week continuous intravenous infusion at a dose of 15 μg/m2/24 hours.

RESULTS

Twenty-one patients were treated, of whom 16 patients became MRD negative. One patient was not evaluable due to a grade 3 adverse event leading to treatment discontinuation. Among the 16 responders, 12 patients had been molecularly refractory to previous chemotherapy. Probability for relapse-free survival is 78% at a median follow-up of 405 days. The most frequent grade 3 and 4 adverse event was lymphopenia, which was completely reversible like most other adverse events.

CONCLUSION

Blinatumomab is an efficacious and well-tolerated treatment in patients with MRD-positive B-lineage ALL after intensive chemotherapy. T cells engaged by blinatumomab seem capable of eradicating chemotherapy-resistant tumor cells that otherwise cause clinical relapse.

Molecular diagnosis and risk-adjusted therapy in pediatric hematologic malignancies: a primer for pediatricians

Progress in the care of the hematologic malignancies of childhoond has been one of the proudest success stories in modern pediatrics. The cure rates of these diseases have improved from essentially zero in the 1950's and early 1960's to cure rates that range from 65%-90% in modern centers. While the largest improvements have been made in the most common (and the lower risk subtypes) of Acute Lymphoblastic Leukemia (ALL), there has also been significant progress in both the higher risk forms of ALL (i.e. Philadelphia chromosome positive, Ph+ ALL) and in Acute Myeloid Leukemia (AML). This progress has been achieved by the careful and stepwise identification of clinical, cytogenetic, molecular, and most recently response-based prognostic criteria, that now allow oncologists to focus the intensity of the therapy more closely to what is required to cure individual subgroups of patients.

CONCLUSION

Pediatricians need to be familiar with the changes in diagnostic and therapeutic approaches, because these changes have impact on: the laboratory tests that should be ordered at the time of specialist referral; counseling of patients and their families; and with the advent of "shared care models" pediatricians will need to be more involved in the general, supportive, and long-term care of these patients.

Improved prognosis for older adolescents with acute lymphoblastic leukemia

PURPOSE

The prognosis for older adolescents and young adults with acute lymphoblastic leukemia (ALL) has been historically much worse than that for younger patients. We reviewed the outcome of older adolescents (age 15 to 18 years) treated in four consecutive Total Therapy studies to determine if recent improved treatment extended to this high-risk group.

PATIENTS AND METHODS

Between 1991 and 2007, 963 pediatric patients, including 89 older adolescents, were enrolled on Total Therapy studies XIIIA, XIIIB, XIV, and XV. In the first three studies, treatment selection was based on presenting clinical features and leukemic cell genetics. In study XV, the level of residual disease was used to guide treatment, which featured intensive methotrexate, glucocorticoid, vincristine, and asparaginase, as well as early triple intrathecal therapy for higher-risk ALL.

RESULTS

The 89 older adolescents were significantly more likely to have T-cell ALL, the t(4;11)(MLL-AF4), and detectable minimal residual disease during or at the end of remission induction; they were less likely to have the t(12;21)(ETV6-RUNX1) compared with younger patients. In the first three studies, the 44 older adolescents had significantly poorer event-free survival and overall survival than the 403 younger patients. This gap in prognosis was abolished in study XV: event-free survival rates at 5 years were 86.4% ± 5.2% (standard error) for the 45 older adolescents and 87.4% ± 1.7% for the 453 younger patients; overall survival rates were 87.9% ± 5.1% versus 94.1% ± 1.2%, respectively.

CONCLUSION

Most older adolescents with ALL can be cured with risk-adjusted intensive chemotherapy without stem-cell transplantation.

Recent research advances in childhood acute lymphoblastic leukemia

Recent progress in risk-adapted treatment for childhood acute lymphoblastic leukemia has secured 5-year event-free survival rates of approximately 80% and 5-year survival rates approaching 90%. With improved systemic and intrathecal chemotherapy, it is now feasible to omit safely in all patients prophylactic cranial irradiation, which was once a standard treatment. As high-resolution, genome-wide analyses of leukemic and normal host cells continue to identify novel subtypes of lymphoblastic leukemia and provide new insights into leukemogenesis, we can look forward to the time when all cases of this disease will be classified according to specific genetic abnormalities, some of which will yield "druggable" targets for more effective and less toxic treatments. Meanwhile, it is sobering to consider that a significant fraction of leukemia survivors will develop serious health problems within 30 years of their initial diagnosis. This underlines the need to introduce early countermeasures to reduce late therapy-related effects. The ultimate challenge is to gain a clear understanding of the factors that give rise to childhood leukemia in the first place, and enable preventive strategies to be devised and implemented.

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.

Prognostic factors in adult acute lymphoblastic leukaemia

Treatment of acute lymphoblastic leukaemia (ALL) in adults presents a formidable challenge. While overall results have improved over the past 3 decades, the long-term survival for patients aged less than 60 years is only in the range of 30-40% and is 10-15% if between 60 and 70 years and <5% for those over 70 years. The historic lack of clear-cut biological prognostic factors has led to over- or under-treatment of some patients. Response to initial therapy is an important prognosticator of outcome based on disease biology, as well as pharmacogenetics, which include the patient's response to drugs given. The more widespread availability of allogeneic transplantation and reduced-intensity regimens for older patients have opened up this curative modality to a greater number of patients. Hopefully, those options, as well as novel cytogenetic and molecular markers, will enable a better selection of patients who undergo intensive therapies and finally break the 30-40% cure barrier for adults with ALL.

NCI First International Workshop on the Biology, Prevention, and Treatment of Relapse after Allogeneic Hematopoietic Stem Cell Transplantation: report from the Committee on Disease-Specific Methods and Strategies for Monitoring Relapse following Allogeneic Stem Cell Transplantation. Part I: Methods, acute leukemias, and myelodysplastic syndromes

Relapse has become the major cause of treatment failure after allogeneic stem cell transplantation. Outcome of patients with clinical relapse after transplantation generally remains poor, but intervention prior to florid relapse improves outcome for certain hematologic malignancies. To detect early relapse or minimal residual disease, sensitive methods such as molecular genetics, tumor-specific molecular primers, fluorescein in situ hybridization, and multiparameter flow cytometry (MFC) are commonly used after allogeneic stem cell transplantation to monitor patients, but not all of them are included in the commonly employed disease-specific response criteria. The highest sensitivity and specificity can be achieved by molecular monitoring of tumor- or patient-specific markers measured by polymerase chain reaction-based techniques, but not all diseases have such targets for monitoring. Similar high sensitivity can be achieved by determination of donor chimerism, but its specificity regarding detection of relapse is low and differs substantially among diseases. Here, we summarize the current knowledge about the utilization of such sensitive monitoring techniques based on tumor-specific markers and donor cell chimerism and how these methods might augment the standard definitions of posttransplant remission, persistence, progression, relapse, and the prediction of relapse. Critically important is the need for standardization of the different residual disease techniques and to assess the clinical relevance of minimal residual disease and chimerism surveillance in individual diseases, which in turn, must be followed by studies to assess the potential impact of specific interventional strategies.