Newly diagnosed acute lymphoblastic leukemia in China (I): abnormal genetic patterns in 1346 childhood and adult cases and their comparison with the reports from Western countries

[Clinical features and prognosis of high hyperdiploid childhood acute lymphoblastic leukemia: a multicenter retrospective analysis in Fujian Province, China]

OBJECTIVES

To study the clinical features and prognosis of high hyperdiploid (HHD) childhood acute lymphoblastic leukemia (ALL).

METHODS

A retrospective analysis was performed on the medical data of 1 414 children who were newly diagnosed with ALL and were admitted to five hospitals in Fujian Province of China from April 2011 to December 2020. According to karyotype, they were divided into two groups: HHD (n=172) and non-HHD (n=1 242). The clinical features and treatment outcome were compared between the two groups, and the factors influencing the prognosis were further explored.

RESULTS

Among the 1 414 children with ALL, 172 (12.16%) had HHD. Compared with the non-HHD group, the HHD group had significantly lower proportions of children with risk factors for poor prognosis at diagnosis (age of onset ≥10 years or <1 year, white blood cell count ≥50×10⁹/L, and T-cell phenotype) or positive fusion genes (TEL-AML1, BCR-ABL1, E2A-PBX1, and MLL gene rearrangement) (P<0.05). The HHD group had a significantly higher proportion of children with minimal residual disease (MRD) <0.01% at the end of induction chemotherapy (P<0.05). The 10-year event-free survival (EFS) rate and overall survival (OS) rate in the HHD group were significantly higher than those in the non-HHD group (P<0.05). The univariate analysis showed that the number of chromosomes of 58-66, trisomy of chromosome 10, trisomy of chromosome 17, bone marrow MRD <1% on day 15 or 19 of induction chemotherapy, and bone marrow MRD <0.01% on day 33 or 46 of induction chemotherapy were associated with a higher EFS rate (P<0.05), and trisomy of chromosome 10 was associated with a higher OS rate (P<0.05). The multivariate Cox analysis showed that trisomy of chromosome 17 was closely associated with a high EFS rate (P<0.05).

CONCLUSIONS

The ALL children with HHD have few risk factors for poor prognosis at diagnosis and often have good prognosis. The number of chromosomes and trisomy of specific chromosomes are associated with prognosis in these children.

Cytogenetics and Molecular Genetics in Pediatric Acute Lymphoblastic Leukemia (ALL) and Its Correlation with Induction Outcomes

Arathi SrinivasanAims  The aim was to study cytogenetics and molecular genetic profile in pediatric B-acute lymphoblastic leukemia (ALL) and correlate it with induction outcomes. Subjects and Methods  A retrospective study of cytogenetics and molecular genetics of 98 children with B-cell ALL from January 2013 to May 2018 was done. Cytogenetics and molecular genetics were done in the bone marrow using multiplex reverse transcription polymerase chain reaction and G-banded karyotyping, respectively. Minimal residual disease (MRD) assessment was done at the end of induction by flowcytometry. Results  Of the 98 children, 83 (84.6%) had evaluable cytogenetics, with 11 (13.25%) being abnormal karyotypes. Of the 11 abnormal karyotypes, seven children (8.4%) had hyperdiploidy, one had hypodiploidy, and three had miscellaneous findings. In molecular genetics, TEL-AML1 (ETV6/RUNX1)[t(12;21)] was the most common fusion gene abnormality (12.2% [12/98]), followed by E2A-PBX1 [t(1;19)] (5%), BCR/ABL1 [t(9;22)] (3%), and MLL-AF4 [t(4;11)] (1%). All the 98 children attained morphologic remission at the end of induction. All children with hyperdiploidy (7/7) attained remission and MRD negativity, but one expired during maintenance chemotherapy of disseminated tuberculosis. The child with hypodiploidy was MRD-positive. Three (25%) children with t (12;21) were MRD-positive. All children with Ph + ALL, t(1:19), and t(4;11) were MRD-negative. Fifty-two children had no detected abnormalities, six of whom had MRD positivity (11.5%). Conclusion  Cytogenetic and molecular genetic subgrouping prognosticates ALL outcomes. Although 25% of TEL-AML + children had MRD positivity, larger studies are required to validate the same. End-of-induction MRD outcomes did not correlate with chromosomal aberrations.

Ectopic expression of a combination of 5 genes detects high risk forms of T-cell acute lymphoblastic leukemia

BACKGROUND

T cell acute lymphoblastic leukemia (T-ALL) defines a group of hematological malignancies with heterogeneous aggressiveness and highly variable outcome, making therapeutic decisions a challenging task. We tried to discover new predictive model for T-ALL before treatment by using a specific pipeline designed to discover aberrantly active gene.

RESULTS

The expression of 18 genes was significantly associated with shorter survival, including ACTRT2, GOT1L1, SPATA45, TOPAZ1 and ZPBP (5-GEC), which were used as a basis to design a prognostic classifier for T-ALL patients. The molecular characterization of the 5-GEC positive T-ALL unveiled specific characteristics inherent to the most aggressive T leukemic cells, including a drastic shut-down of genes located on the mitochondrial genome and an upregulation of histone genes, the latter characterizing high risk forms in adult patients. These cases fail to respond to the induction treatment, since 5-GEC either predicted positive minimal residual disease (MRD) or a short-term relapse in MRD negative patients.

CONCLUSION

Overall, our investigations led to the discovery of a homogenous group of leukemic cells with profound alterations of their biology. It also resulted in an accurate predictive tool that could significantly improve the management of T-ALL patients.

Retrospective Study of B Lymphoblastic Leukemia to Assess the Prevalence of TEL/AML1 in South India: A Study of 214 Cases and Review of Literature

Introduction Translocation t(12;21)(p13;q22), a recurrent and an invisible chromosomal abnormality, resulting in TEL/AML1 gene fusion, associated with good prognosis, has been described to be a common abnormality, in children with B-acute lymphoblastic leukemia (B-ALL).

Objectives The initial observation of very few TEL/AML1 positive patients at this center on testing by fluorescence in situ hybridization (FISH) led to study the prevalence of the abnormality, compare with the global distribution, and evaluate clinical, pathological, molecular, and cytogenetic features in TEL/AML1 positive patients.

Materials and Methods A retrospective study of all B-ALL patients tested for TEL/AML1 gene fusion during the period January 2009 to November 2020 was undertaken. Clinicopathological, molecular, cytogenetic, treatment, and follow-up details were collected. All publications dealing with TEL/AML1 gene rearrangement were reviewed post Google and PubMed search.

Results TEL/AML1gene rearrangement was assessed by FISH in 178 patients and by reverse transcription polymerase chain reaction in 36 patients and detected as the sole abnormality in 8.4% patients with additional genetic abnormalities noted on FISH evaluation. Normal karyotype was noted in 14/18 (77.7%) of these patients and 2 had complex karyotype. Complete blood count revealed hemoglobin to range from 35 to 116 g/L (median: 74 g/L), white blood count: 1.01–110×109/L (median: 7.8×109/L), platelet counts: 10–115×109/L (median: 42×109/L), blast count in peripheral smear: 0–98% (median: 41%). Immunophenotyping demonstrated 94.4% were CD34 positive, common acute lymphoblastic leukemia associated antigen (CALLA) positive with aberrant expression of CD13, CD33, CD56, singly or in combination in 58.8%.

Conclusion TEL/AML1 fusion is rare in Indian patients with B-ALL and appears to be much rarer in our region. The detection of relevant specific abnormalities is of fundamental importance in B-ALL patients and these geographic variations can be used in defining management policies.

Cytogenetic Characteristics of Childhood Acute Lymphoblastic Leukemia: A Study of 1541 Chinese Patients Newly Diagnosed between 2001 and 2014

OBJECTIVE

Cytogenetic abnormalities have been proven to be the most valuable parameter for risk stratification of childhood acute lymphoblastic leukemia (ALL). However, studies on the prevalence of cytogenetic abnormalities and their correlation to clinical features in Chinese pediatric patients are limited, especially large-scale studies.

METHODS

We collected the cytogenetics and clinical data of 1541 children newly diagnosed with ALL between 2001 and 2014 in four Chinese hospitals, and retrospectively analyzed their clinical features, prognosis and risk factors associated with pediatric ALL.

RESULTS

All of these patients had karyotyping results, and some of them were tested for fusion genes by fluorescence in situ hybridization or reverse-transcription polymerase chain reaction. Overall, 930 cases (60.4%) had abnormal cytogenetics in this study, mainly including high hyperdiploidy (HHD, n=276, 17.9%), hypodiploidy (n=74, 4.8%), t(12;21)/TEL-AML1 (n=260, 16.9%), t(1;19)/E2A-PBX1 (n=72, 4.7%), t(9;22)/BCR-ABL (n=64, 4.2%), and t(v;11q23)/MLL rearrangements (n=40, 2.6%). The distribution of each cytogenetic abnormality was correlated with gender, age, white blood cell count at diagnosis, and immunophenotype. In addition, multivariate analysis suggested that t(v;11q23)/MLL rearrangements (OR: 2.317, 95%CI: 1.219-3.748, P=0.008) and t(9;22)/BCR-ABL (OR: 2.519, 95%CI: 1.59-3.992, P<0.001) were independent risk factors for a lower event-free survival (EFS) rate in children with ALL, while HHD (OR: 0.638, 95%CI: 0.455-0.894, P=0.009) and t(12;21)/TEL-AML1 (OR: 0.486, 95%CI: 0.333-0.707, P<0.001) were independent factors of a favorable EFS.

CONCLUSION

The cytogenetic characteristics presented in our study resembled other research groups, emphasizing the important role of cytogenetic and molecular genetic classification in ALL, especially in B-ALL.

The Prenatal Origin of Childhood Leukemia: Potential Applications for Epidemiology and Newborn Screening

Childhood leukemias are heterogeneous diseases with widely differing incident rates worldwide. As circulating tumors, childhood acute leukemias are uniquely accessible, and their natural history has been described in greater detail than for solid tumors. For several decades, it has been apparent that most cases of childhood acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) initiate in utero. Circumstantial evidence in support of this contention includes the young age of onset and high rate of concordance among identical twins. "Backtracking" of leukemic somatic mutations, particularly gene translocations, to cord blood and dried blood spots collected during the perinatal period has provided molecular proof of prenatal leukemogenesis. Detection of a patient's leukemia translocation in easily accessible birth samples, such as dried blood spots, is straightforward with the knowledge of their idiosyncratic breakpoints. However, to translate these findings into population-based screening and leukemia prevention requires novel methods able to detect translocations at all possible breakpoints when present in a low frequency of cells. Several studies have attempted to screen for leukemic translocations, mainly the common ETV6-RUNX1 translocation, in cord blood samples from healthy children. Most studies have reported finding translocations in healthy children, but estimates of prevalence have varied widely and greatly exceed the incidence of leukemia, leading to concerns that technical artifact or contamination produced an artificially inflated estimate of translocation prevalence at birth. New generation techniques that capture the presence of these translocations at birth have the potential to vastly increase our understanding of the epidemiology of acute leukemias. For instance, if leukemic translocations are present at birth in a far higher proportion of children than eventually develop acute leukemia, what are the exposures and somatic molecular events that lead to disease? And could children with translocations present at birth be targeted for prevention of disease? These questions must be answered before large-scale newborn screening for leukemia can occur as a public health initiative. Here, we review the literature regarding backtracking of acute leukemias and the prevalence of leukemic translocations at birth. We further suggest an agenda for epidemiologic research using new tools for population screening of leukemic translocations.

Anti-CD19 CAR-T cell therapy bridge to HSCT decreases the relapse rate and improves the long-term survival of R/R B-ALL patients: a systematic review and meta-analysis

Chimeric antigen receptor (CAR) T cell therapy improves the remission rate of refractory/relapsed B-acute lymphoblastic leukemia (R/R B-ALL) patients, but the relapse rate remains high. Recent studies suggest patients who underwent post-chimeric antigen receptor T cell therapy hematopoietic stem cell transplantation (post- HSCT) would achieve durable remission and better survival, but this remains controversial. To this end, we conducted a meta-analysis to assess the role of post-HSCT in R/R B-ALL. The Cochrane Library, Embase, and PubMed were used to identify relevant studies; the latest search update was on July 05, 2020. We used the Cochran Q test and I-squared statistics to test for heterogeneity among the studies analyzed. The fixed model and random model were used to combine results when appropriate. We performed all statistical analyses with Stata 12, and P < 0.05 was considered statistically significant. We included 18 studies with 758 patients in the meta-analysis. Our results indicated that post-HSCT was associated with lower relapse rate (RR: 0.40, 95% CI: 0.32-0.50, P = 0.000), better overall survival (HR: 0.37, 95% CI: 0.19-0.71, P = 0.003), better leukemia-free survival (HR: 0.20, 95% CI: 0.10-0.40, P = 0.000). However, post-HSCT did not influence OS in Caucasians, and CAR-T cells with CD28 co-stimulation factor bridged to HSCT did not influence OS. Post-HSCT decreased the relapse rate and improved the long-term survival of R/R B-ALL patients. R/R B-ALL patients would benefit from post-HSCT after CAR-T cell therapy.

Treatment response, survival, safety, and predictive factors to chimeric antigen receptor T cell therapy in Chinese relapsed or refractory B cell acute lymphoblast leukemia patients

This study aimed to evaluate treatment response, survival, safety profiles, and predictive factors to chimeric antigen receptor T cell (CAR-T) therapy in Chinese patients with relapsed or refractory B cell acute lymphoblast leukemia (R/R B-ALL). 39R/R B-ALL patients who underwent CAR-T therapy were included. Baseline data were collected from patients’ electronic medical records. Patients’ peripheral bloods, bone marrow aspirates, and biopsies were obtained for routine examination, and treatment response and survival profiles as well as adverse events were evaluated. The rates of complete remission (CR), CR with minimal residual disease (MRD) negative/positive, and bridging to hematopoietic stem-cell transplantation (HSCT) were 92.3%, 76.9%, 15.4%, and 43.6%, respectively. The median event-free survival (EFS) was 11.6 months (95% confidence interval (CI): 4.0–19.2 months) and median overall survival (OS) was 14.0 months (95% CI: 10.9–17.1 months). Bridging to HSCT independently predicted better EFS and OS, while high bone marrow blasts level independently predicted worse EFS. The incidence of cytokine release syndrome (CRS) was 97.4%, and refractory disease as well as decreased white blood cell independently predicted higher risk of severe CRS. Other common adverse events included hematologic toxicities (grade I: 5.1%, grade II: 7.7%, grade III: 17.9%, grade IV: 69.2%), neurotoxicity (28.2%), infection (38.5%), and admission for intensive care unit (10.3%). In conclusion, CAR-T therapy presents with promising treatment response, survival and safety profiles, and higher disease burden predicts worse survival as well as increased risk of severe CRS in Chinese R/R B-ALL patients.

Genetic mutational analysis of pediatric acute lymphoblastic leukemia from a single center in China using exon sequencing

Background

Acute lymphoblastic leukemia (ALL), the most common childhood malignancy, is characterized by recurring structural chromosomal alterations and genetic alterations, whose detection is critical in diagnosis, risk stratification and prognostication. However, the genetic mechanisms that give rise to ALL remain poorly understood.

Methods

Using next-generation sequencing (NGS) in matched germline and tumor samples from 140 pediatric Chinese patients with ALL, we landscaped the gene mutations and estimated the mutation frequencies in this disease.

Results

Our results showed that the top driver oncogenes having a mutation prevalence over 5% in childhood ALL included KRAS (8.76%), NRAS (6.4%), FLT3 (5.7%) and KMT2D (5.0%). While the most frequently mutated genes were KRAS, NRAS and FLT3 in B cell ALL (B-ALL), the most common mutations were enriched in NOTCH1 (23.1%), FBXW7 (23.1%) and PHF6 (11.5%) in T cell ALL (T-ALL). These mutant genes are involved in key molecular processes, including the Ras pathway, the Notch pathway, epigenetic modification, and cell-cycle regulation. Strikingly, more than 50% of mutations occurred in the high-hyperdiploid (HeH) ALL existed in Ras pathway, especially FLT3 (20%). We also found that the epigenetic regulator gene KMT2D, which is frequently mutated in ALL, may be involved in driving leukemia transformation, as evidenced by an in vitro functional assay.

Conclusion

Overall, this study provides further insights into the genetic basis of ALL and shows that Ras mutations are predominant in childhood ALL, especially in the high-hyperdiploid subtype in our research.

Targeted sequencing aids in identifying clonality in chronic myelomonocytic leukemia

Chronic myelomonocytic leukemia (CMML) typically shows monocytosis in the peripheral blood (PB), which must be differentiated from reactive monocytosis. To determine the clonality of CMML, we performed molecular and cytogenetic analysis in Korean patients. To investigate whether monocytes in the PB harbored clonal mutational changes, we performed single-cell sequencing after selecting monocytes, neutrophils, and lymphocytes by morphology-aided laser microdissection. Targeted sequencing was performed in 35 patients with CMML with 41 bone marrow samples. Single-cell analysis was performed in two cases. Most (94.3%) patients harbored at least one variant, in genes considered as potential therapeutic targets, while cytogenetic aberrations occurred in only 28.6% of cases. ASXL1 (54.3%), SRSF2 (37.1%), NRAS (31.4%), and TET2 (25.7%) were frequently mutated, with lower frequencies of TET2 mutation and higher frequencies of NRAS, DNMT3A (17.1%), and NPM1 (11.4%) mutations compared to in previous studies of Caucasians. Patients with SETBP1 mutation and those with more than two variants showed poorer survival than those without mutation (P < 0.001 and P = 0.007, respectively). Most (70.8%) variants were detected at diagnosis and follow-up with no significant differences in variant allele frequency, warranting sequencing during follow-up if diagnostic samples were unavailable. Single-cell analysis revealed clonal monocytes with mutations, and the same mutations were also identified in lymphocytes and neutrophils. Targeted sequencing aided in clonality detection in most patients with CMML and single-cell sequencing facilitated identification of clonal monocytes and the co-existence of mutations in non-myeloid cells, suggesting that certain mutations are acquired by pluripotent stem cells.

Genetic variants and clinical significance of pediatric acute lymphoblastic leukemia

Background

Acute lymphoblastic leukemia (ALL), the most common childhood malignancy, is characterized by molecular aberrations. Recently, genetic profiling has been fully investigated on ALL; however, the interaction between its genetic alterations and clinical features is still unclear. Therefore, we investigated the effects of genetic variants on ALL phenotypes and clinical outcomes.

Methods

Targeted exome sequencing technology was used to detect molecular profiling of 140 Chinese pediatric patients with ALL. Correlation of genetic features and clinical outcomes was analyzed.

Results

T-cell ALL (T-ALL) patients had higher initial white blood cell (WBC) count (34.8×10⁹/L), higher incidence of mediastinal mass (26.9%), more relapse (23.1%), and enriched NOTCH1 (23.1%), FBXW7 (23.1%) and PHF6 (11.5%) mutations. Among the 18 recurrently mutated genes, SETD2 and TP53 mutations occurred more in female patients (P=0.041), NOTCH1 and SETD2 mutants were with higher initial WBC counts (≥50×10⁹/L) (P=0.047 and P=0.041), JAK1 mutants were with higher minimal residual disease (MRD) level both on day 19 and day 46 (day 19 MRD ≥1%, P=0.039; day 46 MRD ≥0.01%, P=0.031) after induction chemotherapy. Multivariate analysis revealed that initial WBC counts (≥50×10⁹/L), MLLr, and TP53 mutations were independent risk factors for 3-year relapse free survival (RFS) in ALL. Furthermore, TP53 mutations, age (<1 year or ≥10 years), and MLLr were independently associated with adverse outcome in B-cell ALL (B-ALL).

Conclusions

MLLr and TP53 mutations are powerful predictors for adverse outcome in pediatric B-ALL and ALL. Genetic profiling can contribute to the improvement of prognostication and management in ALL patients.

Reassessment of the Risk-stratified GD-2008 ALL Protocol

OBJECTIVE

To explore the clinical features and outcomes of relapsed childhood acute lymphoblastic leukemia (ALL) at our center, achieve the early detection of risk factors for recurrence and assess the risk-stratified Guangdong (GD)-2008 ALL protocol.

MATERIALS AND METHODS

In total, 59 Chinese childhood ALL patients treated with the GD-2008 ALL protocol who relapsed between July 2008 and March 2015 were enrolled in this study. Their clinical features and outcomes were retrospectively analyzed and compared with those of 218 patients who achieved continuous complete remission.

RESULTS

Of the 285 study participants, 8 died of treatment-related infections or other complications before remission, 218 achieved continuous complete remission, and 59 patients relapsed, yielding a relapse rate of 20.7%. The number of relapsed patients in the standard-risk, intermediate-risk, and high-risk groups were 15 (17.0%), 27 (19.7%), and 17 (32.7%), respectively. Risk factors included age 10 years and above at first diagnosis, white blood cell (WBC) count ≥50×10/L, poor prednisone response, failure to achieve bone marrow complete remission at day 15 of induction chemotherapy. High-risk stratification and a high level (≥0.1%) of minimal residual disease at day 33 were the risk factors for relapse. Multivariate analysis showed that a high WBC at first diagnosis was an independent risk factor for relapse (P=0.000).

CONCLUSION

For the GD-2008 ALL risk stratification based on age and initial WBC, 10 years of age and WBC 50×10/L can be used as cut-offs. Patients at high risk benefited from the GD-2008 ALL protocol. In addition, the impact of minimal residual disease on prognosis should be considered.

MicroRNA-9 suppresses cancer proliferation and cell cycle progression in acute lymphoblastic leukemia with inverse association of neuropilin-1

Acute lymphoblastic leukemia (ALL) is one of the most common and most malign childhood cancers. In this work, we investigated the expression and function of human mature microRNA-9 (miR-9) in ALL. In ALL in vitro cell lines and in situ clinical specimens, gene expression of miR-9 was tested by qRT-PCR. MiR-9 was overexpressed in CEM/C1 and Molt-3 cells to investigate its possible anti-cancer effects on ALL in vitro proliferation, cell-cycle progression, and in vivo explant growth. The possible downstream target of miR-9, neuropilin-1 (NRP1), was examined by dual-luciferase activity assay, qRT-PCR, and Western blot. NRP1was upregulated in miR-9-overexpressed CEM/C1 and Molt-3 cells to investigate the functional involvement of NRP1 in miR-9-mediated regulation on ALL in vitro proliferation and cell-cycle progression. MiR-9 was downregulated in ALL cell lines and leukemic T-cells of ALL patients. Lentivirus-mediated miR-9 overexpression inhibited ALL in vitro proliferation, cell-cycle progression, and in vivo explant growth. NRP1 was confirmed be the downstream target of miR-9, and inversely modulated by miR-9 in ALL. NRP1 upregulation reversed the anti-cancer regulations of miR-9 on ALL in vitro proliferation and cell-cycle progression. MiR-9 is downregulated in ALL. Overexpressing miR-9 may inhibit ALL development, possible through its downstream target of NRP1.

Analysis of common cytogenetic abnormalities in New Zealand pediatric ALL shows ethnically diverse carriage of ETV6-RUNX1, without a corresponding difference in survival

BACKGROUND

The frequency of common cytogenetic abnormalities in pediatric acute lymphoblastic leukemia (ALL) is known to vary by geographic location and ethnic origin. This study aimed to determine the frequency of hypodiploidy, ETV6-RUNX1, BCR-ABL1, and MLL rearrangement within New Zealand's pediatric ALL population and to assess whether the frequency of these ALL prognostic markers varies according to ethnicity.

PROCEDURE

The New Zealand Children's Cancer Registry provided information for all registered pediatric ALL patients that were diagnosed between 2000 and 2009, with medical records available for 246 patients. Each patient's medical record was reviewed to determine the frequency of hypodiploidy, ETV6-RUNX1, BCR-ABL1, MLL rearrangement, and cell lineage. Chi-square tests for independence were undertaken to compare the frequencies of cytogenetic abnormalities according to prioritized ethnicity.

RESULTS

The frequency of cytogenetic ALL abnormalities in the New Zealand pediatric population were consistent with international reference values. A low frequency of ETV6-RUNX1 was evident for Maori pediatric ALL patients (5.4%, P = 0.018), when compared to Pacific peoples (21.1%) and non-Maori/non-Pacific peoples (27.4%). This has not impacted on outcome, however, with equivalent 5-year overall survival being observed in Maori (89.4%) compared to Pacific peoples (92.0%) and non-Maori/non-Pacific peoples (90.2%).

CONCLUSIONS

A lower frequency of the favorable prognostic marker ETV6-RUNX1 was observed in Maori pediatric ALL patients. This did not translate into poorer survival. Future research into biological and nonbiological prognostic factors in this patient population may assist in explaining this finding.

Genomic Profiling of Adult and Pediatric B-cell Acute Lymphoblastic Leukemia

Genomic landscapes of 92 adult and 111 pediatric patients with B-cell acute lymphoblastic leukemia (B-ALL) were investigated using next-generation sequencing and copy number alteration analysis. Recurrent gene mutations and fusions were tested in an additional 87 adult and 93 pediatric patients. Among the 29 newly identified in-frame gene fusions, those involving MEF2D and ZNF384 were clinically relevant and were demonstrated to perturb B-cell differentiation, with EP300-ZNF384 inducing leukemia in mice. Eight gene expression subgroups associated with characteristic genetic abnormalities were identified, including leukemia with MEF2D and ZNF384 fusions in two distinct clusters. In subgroup G4 which was characterized by ERG deletion, DUX4-IGH fusion was detected in most cases. This comprehensive dataset allowed us to compare the features of molecular pathogenesis between adult and pediatric B-ALL and to identify signatures possibly related to the inferior outcome of adults to that of children. We found that, besides the known discrepancies in frequencies of prognostic markers, adult patients had more cooperative mutations and greater enrichment for alterations of epigenetic modifiers and genes linked to B-cell development, suggesting difference in the target cells of transformation between adult and pediatric patients and may explain in part the disparity in their responses to treatment.

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The genomic landscapes of adult and pediatric B-ALL were defined by next-generation sequencing of patient samples.

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MEF2D and ZNF384 fusions could perturb B-cell differentiation or induce leukemia in mice and exhibited clinical relevance.

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Adult patients showed greater enrichment for alterations of genes linked to epigenetic modification and B-cell development.

This study comprehensively addressed the genomic signatures of adult versus pediatric B-ALL. The identification of distinct MEF2D and ZNF384 fusions expands the existing knowledge about molecular subtypes of B-ALL in both age groups. RNA-seq data allowed most of the B-ALL cases to be clustered into 8 subgroups related to genetic abnormalities. Notably, adult patients have more cooperative sequence variation mutations than pediatric patients, especially in genes involved in epigenetic regulation and B-cell development. These findings may improve our understanding of leukemogenesis in B-ALL, leading to a more precise genetic classification and the further development of targeted therapy in this disease.

A six gene expression signature defines aggressive subtypes and predicts outcome in childhood and adult acute lymphoblastic leukemia

Abnormal gene expression in cancer represents an under-explored source of cancer markers and therapeutic targets. In order to identify gene expression signatures associated with survival in acute lymphoblastic leukemia (ALL), a strategy was designed to search for aberrant gene activity, which consists of applying several filters to transcriptomic datasets from two pediatric ALL studies. Six genes whose expression in leukemic blasts was associated with prognosis were identified:three genes predicting poor prognosis (AK022211, FASTKD1 and STARD4) and three genes associated with a favorable outcome (CAMSAP1, PCGF6 and SH3RF3). Combining the expression of these 6 genes could successfully predict prognosis not only in the two discovery pediatric ALL studies, but also in two independent validation cohorts of adult patients, one from a publicly available study and one consisting of 62 newly recruited Chinese patients. Moreover, our data demonstrate that our six gene based test is particularly efficient in stratifying MLL or BCR.ABL negative patients. Finally, common biological traits characterizing aggressive forms of ALL in both children and adults were found, including features of dormant hematopoietic stem cells, suggesting new therapeutic strategies.

Fighting against hematological malignancy in China: from unique system to global impact

During recent decades, substantial progress has been made in clinical strategies for treating hematological malignancies. Not only did China benefit from the global progression in the management of acute promyelocytic leukemia, risk-stratification-directed strategies for acute or chronic leukemia and haploidentical hematopoietic stem cell transplantation, the unique system developed by Chinese doctors has also become inspiration for refining global clinical practice. The multicenter trials and collaborations adhering to international standards might further strengthen the global impact and lead the way in specific fields of research worldwide.

Effects of plant-derived anti-leukemic drugs on individualized leukemic cell population profiles in Egyptian patients

Leukemias are a group of cancer types that originate from blood-forming tissues. In this disease, an abnormally large number of immature white blood cells is produced by the bone marrow. The relationship between treatments with plant-derived drugs and leukemia-associated immunophenotypes (LAIPs) of clinically isolated leukemia cells has yet to be established. The aim of the present study was to develop a preliminary clinical prognostic map for commonly expressed LAIPs in patients clinically diagnosed with leukemia, as well as to assess the potential involvement of LAIPs in the response rate to 10 natural products of plant origin. An increased expression of LAIPs, including CD4, CD14, CD33 and CD34, was considered a surrogate marker of the desired response of leukemia cells to treatment with plant-derived drugs. By contrast, the increased expression of the LAIPs, MPO and DR, was associated with poor prognostic outcomes following treatment with the plant-derived drugs. The results showed that 5 of the 10 plant-derived drugs tested induced the expression of several desirable LAIPs biomarkers. These findings clearly highlight the potential treatment efficacy of certain plant-derived drugs against leukemic cell types.

Cytogenetic Profile of De Novo B lineage Acute Lymphoblastic Leukemia: Determination of Frequency, Distribution Pattern and Identification of Rare and Novel Chromosomal Aberrations in Indian Patients

BACKGROUND

Chromosomal aberrations identified in acute lymphoblastic leukemia (ALL) have an important role in disease diagnosis, prognosis and management. Information on karyotype and associated clinical parameters are essential to physicians for planning cancer control interventions in different geographical regions.

MATERIALS AND METHODS

In this study, we present the overall frequency and distribution patterns of chromosomal aberrations in both children and adult de novo B lineage ALL Indian patients using conventional cytogenetics, interphase FISH and multiplex RT-PCR.

RESULTS

Among the 215 subjects, cytogenetic results were achieved in 172 (80%) patients; normal karyotype represented 37.2% and abnormal 62.8% with a distribution as follows: 15.3% hypodiploidy; 10.3% hyperdiploidy; 15.8% t(9;22); 9.8% t(1;19); 3.7% t(12;21); 2.8% t(4;11); 2.8% complex karyotypes. Apart from these, we observed several novel, rare and common chromosomal rearrangements. Also, FISH studies using LSI extra-signal dual-color probes revealed additional structural or numerical changes.

CONCLUSIONS

These results demonstrate cytogenetic heterogeneity of ALL and confirm that the incidence of chromosomal abnormalities varies considerably. To the best of our knowledge, this is one of the largest reported series of cytogenetic investigations in Indian B-lineage ALL cases. In addition, ongoing cytogenetic studies are warranted in larger groups of B-lineage ALL cases to identify newly acquired chromosomal abnormalities that may contribute to disease diagnosis and management.

Acute lymphoblastic leukemia in low and middle-income countries: disease characteristics and treatment results

PURPOSE OF REVIEW

Acute lymphoblastic leukemia is the most common pediatric cancer. The cure rate of this disease is over 80% in developed countries utilizing protocols with very tolerable toxicity. Several factors contributed to this success, including the implementation of large collaborative clinical trials and the better understanding of disease biology allowing for risk-stratified treatment. We will review the current state of the treatment of acute lymphoblastic leukemia in low-income and medium-income countries.

RECENT FINDINGS

The picture differs from country to country, but recent advances have been made in many countries and the cure rates have improved significantly. Tackling problems such as access to care, abandonment of treatment and toxicity of protocols and the development of centers of excellence are critical for continued improvement. Twinning with programs in developed countries and the creation of regional collaborative groups will allow the implementation of risk-directed therapy and better supportive care.

SUMMARY

The experience in low-income countries shows that a structured approach to the treatment of acute lymphoblastic leukemia results in improved survival.

Expression of Ik6 and Ik8 Isoforms and Their Association with Relapse and Death in Mexican Children with Acute Lymphoblastic Leukemia

Expression of the 6 and 8 dominant-negative Ikaros isoforms in pediatric patients with acute lymphoblastic leukemia has been associated with a high risk of relapse and death; due to these isoforms disrupting the differentiation and proliferation of lymphoid cells. The aim of this study was to know the frequency of Ik6 and Ik8 in 113 Mexican ALL-children treated within the National Popular Medical Insurance Program to determine whether there was an association with relapse-free survival, event-free survival and overall survival, and to assess its usefulness in the initial stratification of patients. The expression of these isoforms was analyzed using specific primer sets and nested RT-PCR. The detected transcripts were classified according to the isoforms’s sizes reported. A non-expected band of 300 bp from one patient was analyzed by sequencing. Twenty-six patients expressed Ik6 and/or Ik8 and one of them expressed a variant of Ik8 denominated Ik8-deleted. Although the presence of them was not statistically associated with lower relapse free survival (p = 0.432), event free survival (p = 0.667) or overall survival (p = 0.531), inferior overall survival was observed in patients that expressed these isoforms and showed high or standard risk by age and white blood-cell count at diagnosis. Of the 26 patients Ik6+ and/or Ik8+, 14 did not present adverse events; from them 6 were exclusively Ik6+ and/or Ik8+, and 8 were positive for the other Ikaros isoforms (Ik1, Ik2, Ik5, Ik3A, Ik4, Ik4A, Ik7). In the patients studied, the expression of Ik6 and Ik8 did not constitute an independent prognostic factor for relapse or death related to disease; therefore, they could not be used in the initial risk stratification.

Clinical characteristics of acute lymphoblastic leukemia in male and female patients: A retrospective analysis of 705 patients

The aim of the present study was to compare the clinical characteristics of acute lymphoblastic leukemia (ALL) that occurred in male and female patients at one institution in Southern China. The medical electronic records of Nanfang Hospital, affiliated to Southern Medical University, were searched for patients with a definite diagnosis of ALL that were diagnosed between January 1, 2001 and December 31, 2012. The clinical data of the patients were collected and analyzed. A total of 705 eligible patients were identified. The gender ratio of male to female patients was 1.84:1. The average ages at the time of diagnosis were 16.43 and 19.54 years for male and female patients, respectively (P=0.007). No significant differences were identified in the seasonal occurrence distribution, blood group distribution or ratio for the presence of the Ph chromosome between males and females. However, a higher incidence of T-cell type ALL was identified in males (P=0.023). The present study reveals that ALL demonstrates a male predominance, but similar clinical characteristics of ALL are present in males and females in Southern China.

Sequential and hierarchical chromosomal changes and chromosome instability are distinct features of high hyperdiploid pediatric acute lymphoblastic leukemia

BACKGROUND

Pathogenesis of the non-random accumulation of extra chromosomes in the low and high hyperdiploid (HeL, HeH) pre-B pediatric acute lymphoblastic leukemia (B-pALL) is largely unknown, and has been clarified with respect only to tetrasomic chromosomes. We analyzed the hierarchy of changes in chromosome number and chromosomal instability, as well as clonal heterogeneity and evolution, in the untreated bone marrow cell samples from 214 B-pALL patients.

PROCEDURE

Applying relocation, 2 × 4 color interphase fluorescence in situ hybridization was used to detect copy number alterations (CNAs) of the most commonly involved chromosomes, 4, 6, 10, 14, 17, 18, 21, and X. This approach allowed us to acquire a dataset correlated for all eight parameters.

RESULTS

Based on chromosome number, an average of 6.9 and 10.2, whereas according to unique constellation 15.3 and 26.7 subclones could be identified in the HeL and HeH subgroups, respectively. Cluster analysis revealed the order of CNAs to chromosomes was highly conserved, and network analysis indicated changes in chromosome number were sequential for 80-90% of all numerical aberrations. Significant chromosome instability was revealed in both subgroups of leukemia.

CONCLUSIONS

Data generated using this new approach indicate that chromosomal instability, which causes heterogeneity in the subclonal landscape, and the sequential changes to chromosome numbers, are both determining factors in the pathomechanism of the hyperdiploid B-pALL. These new observations could prompt research into the mitotic machinery of leukemic cells to identify new therapeutic targets for treating this disease.

Parental occupational pesticide exposure and the risk of childhood leukemia in the offspring: findings from the childhood leukemia international consortium

Maternal occupational pesticide exposure during pregnancy and/or paternal occupational pesticide exposure around conception have been suggested to increase risk of leukemia in the offspring. With a view to providing insight in this area we pooled individual level data from 13 case-control studies participating in the Childhood Leukemia International Consortium (CLIC). Occupational data were harmonized to a compatible format. Pooled individual analyses were undertaken using unconditional logistic regression. Using exposure data from mothers of 8,236 cases, and 14,850 controls, and from fathers of 8,169 cases and 14,201 controls the odds ratio (OR) for maternal exposure during pregnancy and the risk of acute lymphoblastic leukemia (ALL) was 1.01 [95% confidence interval (CI) 0.78, 1.30] and for paternal exposure around conception 1.20 (95% 1.06, 1.38). For acute myeloid leukemia (AML), the OR for maternal exposure during pregnancy was 1.94 (CI 1.19, 3.18) and for paternal exposure around conception 0.91 (CI 0.66, 1.24.) based on data from 1,329 case and 12,141 control mothers, and 1,231 case and 11,383 control fathers. Our finding of a significantly increased risk of AML in the offspring with maternal exposure to pesticides during pregnancy is consistent with previous reports. We also found a slight increase in risk of ALL with paternal exposure around conception which appeared to be more evident in children diagnosed at the age of 5 years or more and those with T cell ALL which raises interesting questions on possible mechanisms.

Tetracycline-regulated mouse models of cancer

Genetically engineered mouse models (GEMMs) have proven essential to the study of mammalian gene function in both development and disease. However, traditional constitutive transgenic mouse model systems are limited by the temporal and spatial characteristics of the experimental promoter used to drive transgene expression. To address this limitation, considerable effort has been dedicated to developing conditional and inducible mouse model systems. Although a number of approaches to generating inducible GEMMs have been pursued, several have been restricted by toxic or undesired physiological side effects of the compounds used to activate gene expression. The development of tetracycline (tet)-dependent regulatory systems has allowed for circumvention of these issues resulting in the widespread adoption of these systems as an invaluable tool for modeling the complex nature of cancer progression.

A 50-year journey to cure childhood acute lymphoblastic leukemia

The 50th anniversary of Seminars in Hematology coincides with the 50th anniversary of St. Jude Children's Research Hospital, and both milestones are inexorably linked to studies contributing to the cure of childhood acute lymphoblastic leukemia (ALL). We thought it fitting, therefore, to mark these events by traveling back in time to point out some of the achievements, institutions, study groups, and individuals that have made cure of childhood ALL a reality. In many instances, progress was driven by new ideas, while in others it was driven by new experimental tools that allowed more precise assessment of the biology of leukemic blasts and their utility in selecting therapy. We also discuss a number of contemporary advances that point the way to exciting future directions. Whatever pathways are taken, a clear challenge will be to use emerging genome-based or immunologic-based treatment options in ways that will enhance, rather than duplicate or compromise, recent gains in outcome with classic cytotoxic chemotherapy. The theme of this journey serves as a reminder of the chief ingredient of any research directed to a catastrophic disease such as ALL. It is the audacity of a small group of investigators who confronted a childhood cancer with the goal of cure, not palliation, as their mindset.

Management of adult and paediatric acute lymphoblastic leukaemia in Asia: resource-stratified guidelines from the Asian Oncology Summit 2013

Survival for adults and children with acute lymphoblastic leukaemia has risen substantially in recent years because use of improved risk-directed treatments and supportive care has widened. In nearly all developed countries, multidisciplinary panels of leukaemia experts have formulated clinical practice guidelines in which standard treatment approaches are recommended on the basis of current evidence. However, those guidelines do not take into account resource limitations in low-income countries, including financial and technical challenges. In Asia, huge disparities in economy and infrastructure exist between countries, and even among different regions in some large countries. At a consensus session held as part of the 2013 Asian Oncology Summit in Bangkok, Thailand, a panel of experts summarised recommendations for management of adult and paediatric acute lymphoblastic leukaemia. Strategies were developed for Asian countries on the basis of available financial, skill, and logistical resources and were stratified in a four-tier system according to the resources available in a particular country or region (basic, limited, enhanced, and maximum).

Prognostic significance of monitoring leukemia-associated immunophenotypes by eight-color flow cytometry in adult B-acute lymphoblastic leukemia

Minimal residual disease (MRD) is of the most important factor for predicting prognosis and guiding treatment of acute lymphoblastic leukemia (ALL). In this study, we investigated the prognostic significance of leukemia-associated immunophenotypes (LAIPs) as assessment of index of MRD in 125 adult B-lineage ALL (B-ALL) patients by eight-color flow cytometry. The LAIPs could be identified in 96% and 81.6% of patients with the sensitivity of 10(-4) and 10(-5), respectively. MRD-negative status could clearly predict a favorable 2-year relapse-free survival (RFS) and overall survival (OS) at the end of induction of complete remission and one cycle of consolidation treatment. Moreover, we identified a group of cases with MRD of 0.001% to <0.01%, which showed significantly higher 2-year relapse rate than those with undetectable one. In multivariate analysis, MRD status was associated with RFS or OS independently. Furthermore, MRD assessed by LAIPs and RQ-PCR assay for patients with BCR-ABL fusion gene yielded concordant results in 89.7% of cases. In conclusion, MRD evaluated by eight-color flow cytometry could provide an important tool to assess treatment response and prognosis precisely in adult B-ALL.

Newly diagnosed acute lymphoblastic leukemia in China (II): prognosis related to genetic abnormalities in a series of 1091 cases

The molecular characterization of cytogenetic abnormalities has not only provided insights into the mechanisms of leukemogenesis but also led to the establishment of new treatment strategies targeting these abnormalities and thereby further improve the prognosis of patients. We analyzed the prognosis of 1091 Chinese patients with newly diagnosed acute lymphoblastic leukemia (ALL) and explored the prognostic impacts of a large number of cytogenetic/molecular abnormalities. It was demonstrated that, in both B- and T-ALL settings, the prognosis was negatively correlated to the age as reported to date. For childhood T-ALL patients, it was also documented that the HOX11 expression represented a favorable prognostic factor as it was in adult ones. We identified CRLF2 overexpression as an intermediate-risk marker and Ik6 variant of IKZF1 gene as a high-risk one when stratifying pediatric B-ALL cases according to cytogenetic/molecular risks. We also found that Ik6 variant and CRLF2 overexpression had an important role in dictating the prognosis of Ph-negative patients, which may be useful markers in guiding the treatment of ALL in the future, with tyrosine kinase inhibitors on the other hand reversing the fate of Ph-positive ALL patients.