Detection of minimal residual disease in B-lineage acute lymphoblastic leukaemia by quantitative flow cytometry

The clinical significance of detecting minimal residual disease (MRD) in B-lineage acute lymphoblastic leukaemia (ALL) was evaluated by quantitative flow cytometry using a combination of TdT with CD10 and CD19. 53 patients with B-cell precursor ALL were followed during and after completion of treatment (median follow-up 23 months). Nine patients relapsed and MRD had been detected in six of them, 5–15 weeks before relapse despite morphological complete remission. 43 patients remain in clinical remission and in none of these was MRD detected. Disease-free survival based on the detection of MRD by flow cytometry showed a statistically significant difference between both groups ( P  < 0.0001). The absence of MRD correlates with a low relapse rate, whereas the presence of MRD predicted early relapse. This study has shown that flow cytometry can improve the morphologic assessment of bone marrow (BM) remission status in B-lineage ALL. The finding of < 5% blasts in BM aspirates did not correlate with 'true' remission in a proportion of cases as residual leukaemic blasts were detected by flow cytometry in nine samples from six patients. On the other hand, the presence of > 5% blasts assessed by morphology was not necessarily a feature of relapse in five patients as these cells were shown to have a phenotype identical to normal TdT-negative B-cell precursors. Quantitative flow cytometry was more informative than conventional morphology to assess remission status and showed a strong correlation with clinical outcome. This methodology is useful to define MRD in the majority of patients with B-lineage ALL and should be tested in prospective clinical trials.     

Cytogenetics and genomics in pediatric acute lymphoblastic leukaemia

The last five decades have witnessed significant improvement in diagnostics, treatment and management of children with acute lymphoblastic leukaemia (ALL). These advancements have become possible through progress in our understanding of the genetic and biological background of ALL, resulting in the introduction of risk-adapted treatment and novel therapeutic targets, e.g., tyrosine kinase inhibitors for BCR::ABL1-positive ALL. Further advances in the taxonomy of ALL and the discovery of new genetic biomarkers and therapeutic targets, as well as the introduction of targeted and immunotherapies into the frontline treatment protocols, may improve management and outcome of children with ALL. In this review we describe the current developments in the (cyto)genetic diagnostics and management of children with ALL, and provide an overview of the most important advances in the genetic classification of ALL. Furthermore, we discuss perspectives resulting from the development of new techniques, including artificial intelligence (AI).     

Soluble l-selectin (sCD62L) in relapsed childhood acute lymphoblastic leukaemia

Soluble l-selectin (sCD62L) plasma concentrations at diagnosis and outcome were investigated in 193 children at first relapse of acute lymphoblastic leukaemia (ALL) after treatment according to the Berlin-Frankfurt-Münster relapsed ALL multicentre trials, ALL-REZ BFM 95 and 96. sCD62L was low (< fifth paediatric reference percentile) in 63 (33%) and high (> 95th percentile) in 36 (19%) children, and was independent of remission duration, sex, BCR-ABL fusion or extramedullary disease. High sCD62L was associated with circulating blasts and T-cell phenotype. More initial adverse events occurred in children with high and low levels of sCD62L (23 out of 99) than in those with normal levels (9 out of 94, P = 0.018). Among 75 worst-prognosis patients (risk groups S3/S4, isolated bone marrow relapse occurring less than 6 months after elective cessation of front-line therapy, or T-cell phenotype with bone marrow involvement), 27 had low sCD62L and decreased event-free survival (EFS) probability (PEFS5 = 0.09 at 5 years) and duration (219 d) compared with normal sCD62L (29 out of 75, PEFS5 = 0.24, 640 d, P = 0.01). Low (44 out of 118), normal (72 out of 118), and high (19 out of 118) sCD62L non-S3/S4 patients fared similarly (average PEFS5 = 0.45, 1369 d; P = 0.5). Low sCD62L may be a marker of malignant blasts replacing normal sCD62L-producing haematopoietic cells. In children with first relapse of ALL and worst prognosis, plasma sCD62L may be useful for risk-adapted stratification.     

Adult acute myeloid leukaemia

The curability of acute myeloid leukaemia (AML) in a fraction of adult patients was demonstrated a long time ago. Currently, the probability of cure is consistently above fifty per cent in patients with de novo disease expressing favourable-risk associated cytogenetic features. Even better, the cure rate exceeds 75% in the acute promyelocytic subtype since the introduction of retinoic acid-containing regimens. In the meantime, continuing progress in supportive care systems and stem cell transplant procedures is making myeloablative therapies, when needed, somewhat less toxic—and thereby more effective—than in the recent past. Therefore, evidence is accumulating to indicate an improved therapeutic trend over the years, with the notable exception of older (>55 years) patients with adverse-risk chromosomal aberrations and/or leukemia secondary to myelodysplasia or prior cancer-related chemotherapy and/or radiotherapy. This review conveys the many facets of this progress, focusing on diagnostic subsets, risk classes, newer biological issues and conventional as well as innovative therapeutic interventions with or without autologous/allogeneic stem cell transplantation.     

Treatment of acute lymphoblastic leukaemia (ALL).

Forty-six consecutive patients with acute lymphoblastic leukaemia (ALL), having a median age of 23 years (range 14 to 64), underwent induction and consolidation chemotherapy with weekly parenteral vincristine, adriamycin, l-asparaginase and daily oral prednisone (VAAP), followed by standard central nervous system (CNS) prophylaxis. Maintenance therapy was given for 3 years and consisted of daily 6-mercaptopurine, weekly methotrexate, and monthly intrathecal chemotherapy, with drug intensification comprising either vincristine, adriamycin and l-asparaginase (VAA) or cyclophosphamide, vincristine, cytosine arabinoside and prednisone (COAP). Complete remission (CR) was achieved in 36 patients (78%) and only the FAB L1 morphology was a significant predictive factor (Chi-squared = 3.91: p < 0.05). Eight of the 10 non-responders had significant drug resistance and 3 deaths were associated with marrow hypoplasia. Median follow-up is 52 months. Median duration of CR is 28 months, median survival of all patients is 16 months, and for those who achieved CR is 44 months. There was no difference between the two maintenance arms. Significant prognostic factors for survival are French-American-British (FAB) subtype, in which the L1 is better than L2 (p = 0.05), and age (p = 0.035). Nineteen patients have experienced medullary relapse and 7 (37%) achieved subsequent CR; this is durable in a single patient who underwent allogeneic bone marrow transplantation. Eight patients (17%) had CNS disease at diagnosis; 5 achieved CR and 1 is alive and disease-free at 65+ months. There has been 1 CNS relapse. These results demonstrate that prolonged remissions and survival can be achieved with this protocol and many patients possibly cured. The level of toxicity is acceptable and the pattern of induction failure indicates that a margin exists for intensifying chemotherapy and thereby possibly further improving results.     

Thrombosis and acute lymphoblastic leukaemia

Venous thrombosis is more frequent in patients treated for acute lymphoblastic leukaemia (ALL) than other malignancies and has distinctive causes, clinical features and remedies. The reported incidence varies from 1% to 36%, depending on the chemotherapy protocol and whether the reported cases are symptomatic or detected on screening radiography. The risk is thought to arise from increased thrombin generation at diagnosis combined with reduced thrombin inhibitory capacity due to depletion of circulating anti-thrombin (AT) by asparaginase. A number of patient and treatment variables have been reported to influence the risk of thrombosis including hereditary thrombophilia, early insertion of central venous catheters and exposure to a combination of steroids and asparaginase during induction. Erwinia asparaginase is associated with a lower risk of thrombosis compared with Escherichia coli asparaginase. The majority of symptomatic thromboses are related to central venous catheters and involve the upper venous system. Central nervous system thrombosis involving the cerebral venous sinuses is a unique feature of asparaginase-related thrombosis and is reported to occur in 1-3% of patients. Conclusive evidence to support the use of anti-coagulant treatment or AT concentrates for primary prevention is lacking, as is evidence for the efficacy of AT concentrates in the management of established thrombosis. Preventative strategies are hampered by conflicting data on factors that would enable identification of those at highest risk of thrombosis.     

Abrupt cessation of immunosuppression in a patient with persistent acute lymphoblastic leukaemia following allogeneic transplantation

A 20-year-old man with acute lymphoblastic leukaemia (ALL) in second complete remission underwent sibling donor transplant. Post-transplant there was haematological and immunophenotypic evidence of persisting disease. Cyclosporine was abruptly discontinued and following this the leukaemic clone disappeared. Discontinuation of immunosuppression may be of benefit in leukaemia which persists following transplant.     

Mutation analysis of CD95 (APO-1/Fas) in childhood B-lineage acute lymphoblastic leukaemia

The CD95 system plays an important role in lymphocyte homeostasis, has been implicated in the development of lymphoid malignancies, exerts a tumour suppressor function, and contributes to drug-induced cytotoxicity. We hypothesized that mutations of CD95 may occur in childhood B-lineage acute lymphoblastic leukaemia (ALL), a disease known for its constitutive resistance towards CD95-mediated apoptosis. We investigated 32 primary B-lineage ALL of childhood and five B-lineage ALL cell lines. All primary leukaemias expressed CD95 and bcl-2 to a variable degree. Most of the leukaemias were resistant towards CD95-mediated apoptosis. However, using SSCP analysis, no mutations in the coding and proximal promoter region could be detected. We conclude that the resistance towards CD95-mediated apoptosis observed in most de novo B-lineage ALL is not caused by mutations of the CD95 death receptor.     

Adult acute lymphoblastic leukaemia in Denmark. A national population‐based retrospective study on acute lymphoblastic leukaemia in Denmark 1998–2008

Since July 2008, children and adults 1–45 years, diagnosed with acute lymphoblastic leukaemia (ALL) in Denmark have been treated according to the common Nordic Society for Paediatric Haematology and Oncology ALL2008 protocol. To explore whether this strategy will improve survival compared with historical controls, we performed a retrospective national population‐based study of adult ALL between 1998 and 2008. Patients were identified through the Danish Patobank and the Danish Cancer Registry; data was collected from patient files, and included 277 patients (median age, 47 years, range 15–91 years). The 5‐year projected event‐free survival (pEFS_5y) and overall survival (pOS_5y) for the whole cohort was 27·5% [95% confidence interval (CI) 22·4–33·6] and 34·1% (95% CI 28·7–40·4), respectively. No patient above 65 years survived beyond 5 years from diagnosis. For patients receiving curatively intended treatment, the pEFS_5y and pOS_5y were 36·6% and 44·1%, respectively, with a significantly higher pOS_5y for patients 15–35 years compared with patients 36–65 years (50·7% vs. 38·9%, P = 0·006). Cox multiple regression analysis identified age (Hazard Ratio = 1·7, P < 0·006) as a statistically significant predictor of EFS. The cure rates, not least for the elderly, are unacceptably low, and call for new strategies in the treatment of adult ALL in all age groups.     

Clinical implications of cytogenetic classification in adult acute lymphoblastic leukaemia patients

Cytogenetic analysis performed on pretreated unstimulated, bone marrow/peripheral blood samples of 46 adult patients with acute lymphoblastic leukaemia (ALL) showed sufficient metaphases in 39 patients and insufficient metaphases in 7 patients. G-banded karyotype analysis of these 39 patients revealed nonrandom clonal chromosome abnormalities in 31 patients and apparently normal karyotypes in 8 patients. Numerical abnormalities involving chromosome trisomies and structural abnormalities involving different types of chromosomal translocations and deletions were encountered in varying percentages. These patients were grouped into various cytogenetic subsets on the basis of their karyotype pattern and followed-up to evaluate their prognosis. Patients with apparently normal karyotypes showed good prognosis and those with 6q^– showed intermediate prognosis. But all other patients with hyperdiploid, pseudodiploid and hypodiploid karyotypes were associated with poor prognosis. Cytogenetic classification of ALL patients is thus of clinical importance, as it helps the early identification of clinically important prognostic groups.Abbreviation ALL acute lymphoblastic leukaemia     

Philadelphia positive acute lymphoblastic leukaemia of childhood

On current chemotherapeutic regimens, children with Philadelphia positive acute lymphoblastic leukaemia show a heterogeneous response to treatment. A few respond quickly to treatment and achieve long-term remission. Some fail to achieve remission after induction and the majority respond slowly to treatment. Relapse on treatment is common and remission is sustained in a proportion of cases only after allogeneic stem cell transplantation (allo-SCT). The use of imatinib along with conventional cytoreductive therapy, prior to allo-SCT appears to be the most promising strategy. The future lies in the molecular evaluation of response to treatment and combination targeted chemotherapy.     

Secondary acute lymphoblastic leukaemia is constitutional and probably not related to prior therapy

Very little is known about secondary acute lymphoblastic leukaemia (s‐ALL). This retrospective analysis studied a cohort of s‐ALL patients treated at a single centre between 1994 and 2013, while comparing therapy‐associated ALL (t‐ALL) and antecedent malignancy ALL (am‐ALL) patients. Thirty‐two patients with s‐ALL were identified. The overall incidence was 9·4% among ALL adults while T‐cell s‐ALL was rare (12% of s‐ALLs). The median time interval between two malignant diagnoses was 5·3 years (range: 0·1–28). In contrast to previous reports, most of the s‐ALLs were CD10 +  and without KMT2A (MLL) abnormalities. The overall survival (OS) rates of the entire cohort at 12 and 24 months from ALL diagnosis was 49% and 25%, respectively. Most patients (n = 23, 72%) received prior chemo‐/radio‐therapy for their first malignancy (t‐ALL) and only 9 (28%) did not (am‐ALL). No significant difference was found in the incidence of B‐/T‐ lineage ALL, extramedullary disease, blood count, and the rate of Philadelphia‐positive ALL, nor in the rates of complete remission (P = 0·55) and OS (P = 0·97). This similarity, together with high incidence of family malignancy in both groups, raise the possibility that s‐ALL patients may have an inherent predisposition to malignancies and a history of previous therapy may be of lesser importance in the pathogenesis of s‐ALL.     

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.     

ADAMTSL5 and CDH11: putative epigenetic markers for therapeutic resistance in acute lymphoblastic leukemia

Background and objectives: DNA hypermethylation has been linked to poor treatment outcome in childhood acute lymphoblastic leukemia (ALL). Genes differentially methylated in the chemoresponsive pre-B-ALL compared to chemoresistant pre-B-ALL cases provide potential prognostic markers.

Methods: DNA methylation profiles of five B-ALL childhood patients who achieved morphological complete remission (chemoresponsive) and five B-ALL patients who did not (chemoresistant) after induction treatments as well as four normal controls were compared on 27?000 CpG sites microarray chips. Subsequently, methylation-specific polymerase chain reaction (MSP) on selected hypermethylated genes was conducted on an additional 37 chemoresponsive and 9 chemoresistant B-ALL samples and 2 normal controls.

Results: Both methods were found to be highly correlated. Unsupervised principal component analysis showed that the chemotherapy-responsive and -resistant B-ALL patients could be segregated from one another. Selection of segregated genes at high stringency identified two potential genes (CDH11 and ADAMTSL5). MSP analysis on the larger cohort of samples (42 chemoresponsive, 14 chemoresistant B-ALL samples and 6 normal controls) revealed significantly higher rates of hypermethylation in chemoresistant samples for ADAMTSL5 (93 vs. 38%; p?=?0.0001) and CDH11 (79% vs. 40%, p?Conclusion: Chemoresistant B-ALL patients are associated with increased methylation in ADAMTSL5 and CDH11. These findings need to be validated in a larger group of patients, and the functional biological and prognostic significance of differential methylation needs to be studied further.     

Prognostic factors in elderly acute lymphoblastic leukaemia

A retrospective study was performed on 46 unselected acute lymphoblastic leukaemia (ALL) elderly patients aged 60 years or more. Only 50% of these patients were included in the EORTC cooperative clinical trials, thus confirming the important selection bias in most of the published series on elderly ALL patients. 43% of the elderly patients achieved a complete remission (CR). The median survival was 10 months and the 5-year overall survival was only 7.6±4%. In multivariate analysis, W.H.O. performance status and peripheral blast counts at day 7 were found to significantly influence achievement of CR and survival. In patients with W.H.O. performance status 2, 35% died during induction treatment versus 4% in patients with W.H.O. performance status <2. Patients >70 years old showed a marked drop of the CR rate (27%) compared to those aged 60–69 (67%), and a very high death rate during the induction period (38% versus 4%). This suggests that ALL protocol treatments should be proposed until 70 years in patients with good-performance status, whereas less intensive treatment should be offered to elderly patients with performance status 2 and/or age 70. Peripheral blast counts at day 7 may help to adjust the treatment during induction phase.     

Intraocular relapse of childhood acute lymphoblastic leukaemia

Relapse of childhood acute lymphoblastic leukaemia (ALL) involving the eye is a rare but challenging problem. Twenty cases occurred in patients treated on the Medical Research Council United Kingdom Acute Lymphoblastic Leukaemia XI and ALL97 trials between 1991 and 2001, representing 2.2% of ALL relapses. Seventeen occurred as a first relapse, either in isolation or combined with relapse at another site, and three occurred as a second relapse. All patients with intraocular disease at first relapse were treated with both chemotherapy and radiotherapy, but the doses and protocols used varied. Eleven of these 17 patients are alive and in complete remission with a median follow up of 4 years 2 months from relapse. All 11 children that were treated with a full chemotherapy relapse protocol, together with local radiotherapy have survived. Patients treated with chemotherapy of shorter duration and intensity, despite radiotherapy and/or bone marrow transplantation, did poorly with only one survivor, currently in chronic relapse. Consequently, we suggest that children with eye relapse of ALL be treated with an intensive relapse chemotherapy protocol with local ocular radiotherapy, whether the relapse occurs in isolation or in combination with relapse at another site.     

Time to platelet recovery predicts outcome of patients with de novo acute lymphoblastic leukaemia who have achieved a complete remission

Survival in acute leukaemia depends on the achievement of complete remission (CR). However, CR is not a clear-cut phenomenon and certain variables of its definition could more accurately characterize the quality of the remission. Because platelet recovery > 100 x 10(9)/l is an essential component of CR in acute leukaemia, we hypothesized that time to platelet recovery (TPR) might be predictive of overall survival (OS) or disease-free survival (DFS) in acute lymphoblastic leukaemia (ALL). We analysed TPR in 249 patients with ALL who entered CR after one course of induction chemotherapy and correlated TPR with DFS and OS. TPR was significantly associated with both DFS and OS if it occurred within a maximum of about 60 d from start of therapy. Furthermore, during that time period, the relative risk of death increased with increasing TPR. Although presence of the Philadelphia chromosome was the single most important adverse feature at diagnosis, the effect of TPR on survival continued to be significant within this patient subgroup. This effect was so pronounced that Philadelphia chromosome-positive patients with a TPR of 12 d had a better outcome than Philadelphia chromosome-negative patients with a TPR of 48 d. Thus, a short TPR seems to be able to override adverse characteristics in the outcome of ALL patients treated with chemotherapy. We conclude that a quicker TPR predicts longer DFS and OS in patients with ALL. As platelet counts are obtained almost daily in patients undergoing chemotherapy, TPR can readily be utilized to assess the prognosis of these patients.     

Down syndrome and acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia in children with Down syndrome (ALL-DS) is characterised by unique clinical and biological features. Notable among these are an absence of ALL in DS patients <1 year of age; a lower incidence of favourable and unfavourable chromosomal translocations; heightened sensitivity to methotrexate; and an increased propensity to infections. Although children with ALL-DS have historically fared less well than their non-DS counterparts (ALL-NDS), recent data indicate that outcomes in ALL-DS are now comparable with ALL-NDS with risk-adapted therapies, after adjusting for biological differences between the ALL-DS and ALL-NDS populations. Given the increased risk of ALL-DS patients for treatment-related toxicities, further intensification of therapy may not yield continued improvements in survival. Future investigations in the ALL-DS population should focus on maintaining excellent outcomes while reducing treatment-related complications through novel treatment strategies, such as the integration of targeted noncytotoxic agents.