Additional cytogenetic abnormalities in adults with Philadelphia chromosome-positive acute lymphoblastic leukaemia: a study of the Cancer and Leukaemia Group B

Reduced-intensity chemotherapy with tyrosine kinase inhibitor followed by allogeneic transplantation is effective in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

BACKGROUND/AIMS

To determine the effectiveness of tyrosine kinase inhibitor (TKI) plus reduced-intensity therapy in adult patients with newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL), this retrospective study compared treatment outcomes and induction mortality according to backbone regimen intensity.

METHODS

The data of 132 patients diagnosed with Ph-positive ALL were retrospectively collected from five centers. Patients received imatinib plus intensive chemotherapy (modified VPD, KALLA1407, or hyper-CVAD) or reduced-intensity chemotherapy (EWALL) for curative purposes. This study analyzed 117 patients, of which 35,22,46, and 14 received modified VPD, KALLA1407, hyper-CVAD, and EWALL, respectively. All patients used imatinib as a TKI.

RESULTS

The median age of the patients who received reduced-intensity chemotherapy was 64.4 years, while that of the patients with intensive regimens was 47.5 years. There was no induction death in the reduced-intensity group, while nine patients died in the intensive therapy group. Major molecular response achievement tended to be higher in the intensive chemotherapy group than in the reduced-intensity group. More patients in the intensive chemotherapy group received allogeneic stem cell transplantation (allo-SCT). There was no statistically significant difference in long-term survival between the two groups in terms of relapse-free survival and overall survival rates.

CONCLUSION

When imatinib plus reduced-intensity therapy was used as a frontline treatment, there was no inferiority in obtaining complete remission compared to imatinib plus intensive chemotherapy or significant difference in long-term survival. Since imatinib plus reduced-intensity therapy has limitations in obtaining a deep molecular response, proceeding to allo-SCT should be considered.

Impact of additional cytogenetic aberrations at diagnosis on prognosis of adults patients with Philadelphia chromosome positive acute lymphoblastic leukemia undergoing allogeneic hematopoietic cell transplantation: a retrospective analysis

Additional chromosomal abnormalities(ACAs) at diagnosis are associated with inferior prognosis in chronic myeloid leukemia. However, the prognostic significance of ACAs in adult patients with Philadelphia Chromosome Positive acute lymphoblastic leukemia (Ph + ALL) receiving TKI-targeted drugs and allogeneic hematopoietic stem cell transplantation(HSCT) is unknown. One hundred thirty-six adult patients with Ph + ALL were included in the study and retrospectively analysed, evaluating the effect of ACAs on outcomes of transplantation. ACAs are observed in 60 cases (44%). ACAs detected in more than 5% of cases were defined as major-route and encompass: +der(22), +der(9), + 8, -7 and complex karyotype. The median follow-up was 26.4 months. In the subgroup analyses of major route ACAs, three-year cumulative incidence of relapse (CIR) and progression-free survival(PFS) are statistically significant in + 8[66.7% vs.23.7%, P = 0.024; 77.8% vs. 23.7%, P = 0.0087], -7[53.8% vs. 23.7%, P = 0.035%; 61.5% vs. 32.9%, P = 0.033], and complex karyotypes[42.9% vs. 23.7%, P = 0.027; 47.6% vs. 23.7%] compared with t(9;22) sole. Additionally, the 3-year CIR for Ph + ALL with + der(22) is 44% vs. 23.7% for t(9;22) sole(P = 0.045). The 3-year overall survival (OS) in the - 7 group is 46.5%, which is statistically significant compared with the other groups(P = 0.001). In multivariate analyses, three years CIR and PFS are statistically significant in + der(22), + 8, -7 and complex karyotype compared with t(9;22) sole(P < 0.05). More importantly, Ph + ALL with - 7 was negatively associated with the rate of 3-year OS(P = 0.012). Thus, ACAs at diagnosis appear to have a significant prognostic impact on transplantation outcomes in patients with Ph + ALL.

Predictive and prognostic molecular biomarkers in lymphomas

Recent advances in molecular diagnostics have markedly expanded our understanding of the genetic underpinnings of lymphomas and catalysed a transformation in not just how we classify lymphomas, but also how we treat, target, and monitor affected patients. Reflecting these advances, the World Health Organization Classification, International Consensus Classification, and National Comprehensive Cancer Network guidelines were recently updated to better integrate these molecular insights into clinical practice. We summarise here the molecular biomarkers of lymphomas with an emphasis on biomarkers that have well-supported prognostic and predictive utility, as well as emerging biomarkers that show promise for clinical practice. These biomarkers include: (1) diagnostic entity-defining genetic abnormalities [e.g., B-cell acute lymphoblastic leukaemia (B-ALL) with KMT2A rearrangement]; (2) molecular alterations that guide patients' prognoses (e.g., TP53 loss frequently conferring worse prognosis); (3) mutations that serve as the targets of, and often a source of acquired resistance to, small molecular inhibitors (e.g., ABL1 tyrosine kinase inhibitors for B-ALL BCR::ABL1, hindered by ABL1 kinase domain resistance mutations); (4) the growing incorporation of molecular measurable residual disease (MRD) in the management of lymphoma patients (e.g., molecular complete response and sequencing MRD-negative criteria in multiple myeloma). Altogether, our review spans the spectrum of lymphoma types, from the genetically defined subclasses of precursor B-cell lymphomas to the highly heterogeneous categories of small and large cell mature B-cell lymphomas, Hodgkin lymphomas, plasma cell neoplasms, and T/NK-cell lymphomas, and provides an expansive summary of our current understanding of their molecular pathology.

How to Manage Philadelphia-Positive Acute Lymphoblastic Leukemia in Resource-Constrained Settings

Recent studies have indicated that more than half of adult patients newly diagnosed with Ph+ ALL can now achieve a cure. However, determining the most suitable protocol for less-resourced settings can be challenging. In these situations, we must consider the potential for treatment toxicity and limited access to newer agents and alloSCT facilities. Currently, it is advisable to use less intensive induction regimens for Ph+ ALL. These regimens can achieve high rates of complete remission while causing fewer induction deaths. For consolidation therapy, chemotherapy should remain relatively intensive, with careful monitoring of the BCR-ABL1 molecular transcript and minimal residual disease. AlloSCT may be considered, especially for patients who do not achieve complete molecular remission or have high-risk genetic abnormalities, such as IKZF1-plus. If there is a loss of molecular response, it is essential to screen patients for ABL mutations and, ideally, change the TKI therapy. The T315I mutation is the most common mechanism for disease resistance, being targetable to ponatinib. Blinatumomab, a bispecific antibody, has shown significant synergy with TKIs in treating this disease. It serves as an excellent salvage therapy, aside from achieving outstanding results when incorporated into the frontline.

Cytogenetics in the management of B-cell acute lymphoblastic leukemia: Guidelines from the Groupe Francophone de Cytogénétique Hématologique (GFCH)

Cytogenetic analysis is mandatory at initial assessment of B-cell acute lymphoblastic leukemia (B-ALL) due to its diagnostic and prognostic value. Results from chromosome banding analysis and complementary FISH are taken into account in therapeutic protocols and further completed by other techniques (RT-PCR, SNP-array, MLPA, NGS, OGM). Indeed, new genomic entities have been identified by NGS, mostly RNA sequencing, such as Ph-like ALL that can benefit from targeted therapy. Here, we have attempted to establish cytogenetic guidelines by reviewing the most recent published data including the novel 5th World Health Organization and International Consensus Classifications. We also focused on newly described cytogenomic entities and indicate alternative diagnostic tools such as NGS technology, as its importance is vastly increasing in the diagnostic setting.

Emerging molecular subtypes and therapies in acute lymphoblastic leukemia

Tremendous strides have been made in the molecular and cytogenetic classification of acute lymphoblastic leukemia based on gene expression profiling data, leading to an expansion of entities in the recent International Consensus Classification (ICC) of myeloid neoplasms and acute leukemias and 2022 WHO Classification of Tumours: Haematolymphoid Tumors, 5th edition. This increased diagnostic and therapeutic complexity can be overwhelming, and this review compares nomenclature differences between the ICC and WHO 5th edition publications, compiles key features of each entity, and provides a diagnostic algorithmic approach. In covering B-lymphoblastic leukemia (B-ALL), we divided the entities into established (those present in the revised 4th edition WHO) and novel (those added to either the ICC or WHO 5th edition) groups. The established B-ALL entities include B-ALL with BCR::ABL1 fusion, BCR::ABL1-like features, KMT2A rearrangement, ETV6::RUNX1 rearrangement, high hyperdiploidy, hypodiploidy (focusing on near haploid and low hypodiploid), IGH::IL3 rearrangement, TCF3::PBX1 rearrangement, and iAMP21. The novel B-ALL entities include B-ALL with MYC rearrangement; DUX4 rearrangement; MEF2D rearrangement; ZNF384 or ZNF362 rearrangement, NUTM1 rearrangement; HLF rearrangement; UBTF::ATXN7L3/PAN3,CDX2; mutated IKZF1 N159Y; mutated PAX5 P80R; ETV6::RUNX1-like features; PAX5 alteration; mutated ZEB2 (p.H1038R)/IGH::CEBPE; ZNF384 rearranged-like; KMT2A-rearranged-like; and CRLF2 rearrangement (non-Ph-like). Classification of T-ALL is complex with some variability in how the subtypes are defined in recent literature. It was classified as early T-precursor lymphoblastic leukemia/lymphoma and T-ALL, NOS in the WHO revised 4th edition and WHO 5th edition. The ICC added an entity into early T-cell precursor ALL, BCL11B-activated, and also added provisional entities subclassified based on transcription factor families that are aberrantly activated.

Clinical Application of Biomarkers for Hematologic Malignancies

Over the last decade, significant advancements have been made in the molecular mechanisms, diagnostic methods, prognostication, and treatment options in hematologic malignancies. As the treatment landscape continues to expand, personalized treatment is much more important.

With the development of new technologies, more sensitive evaluation of residual disease using flow cytometry and next generation sequencing is possible nowadays. Although some conventional biomarkers preserve their significance, novel potential biomarkers accurately detect the mutational landscape of different cancers, and also, serve as prognostic and predictive biomarkers, which can be used in evaluating therapy responses and relapses. It is likely that we will be able to offer a more targeted and risk-adapted therapeutic approach to patients with hematologic malignancies guided by these potential biomarkers. This chapter summarizes the biomarkers used (or proposed to be used) in the diagnosis and/or monitoring of hematologic neoplasms.;

Bortezomib-based Anthracycline-free Induction for Pediatric Relapsed ALL as a Bridge to Immunotherapy

BACKGROUND

Immunotherapy may lead to durable remissions in patients with relapsed and refractory acute lymphoblastic leukemia (R/R ALL). Patients receiving immunotherapy with a lower disease burden tend to have improved long-term outcomes and less toxicity. Thus, an induction protocol to achieve lower disease burden is required. Bortezomib added to a 4-drug induction was shown to lead to high rates of remission in R/R ALL patients. Inclusion of anthracyclines in this protocol may preclude most patients, having maximized the cumulative dose of anthracyclines. Thus, our goal was to evaluate anthracycline-free bortezomib-based induction for patients with R/R ALL.

PROCEDURE

We conducted a retrospective analysis of patients treated with bortezomib-based protocols for R/R ALL between 2011 and 2019 at our center. Data regarding toxicity and response rate was collected and analyzed.

RESULTS

Eighteen children with R/R ALL were treated with bortezomib-based induction, 13 of them without anthracyclines. Eleven patients did not complete the induction course: 6 due to toxicity, and 5 due to physician decision to proceed to immunotherapy early. Two events of treatment-related mortality occurred. There was no significant difference in toxicity between patients who treated with anthracycline and those who were not. Ten patients achieved complete remission, with 4 patients having polymerase-chain-reaction minimal residual disease below 10-4. Fifteen patients proceeded directly to immunotherapy: 11 patients received CD19 chimeric-antigen receptor-T-cells, 2 blinatumomab and 2 hematopoietic stem cell transplant.

CONCLUSION

Anthracyclines can be safely omitted from bortezomib-based therapies in patients with R/R ALL, when planning to proceed to immunotherapy.

Unusual B-Lymphoid Blastic Crisis as Initial Presentation of Chronic Myeloid Leukemia Imposes Diagnostic Challenges

Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder, characterized by reciprocal translocation t(9,22) (q34; q11), leading to increased myeloid proliferation. Most cases are diagnosed in the chronic phase (CP). However, a minority of cases can be present in the blastic phase (BP). In most patients with CML-BP, the blasts have a myeloid phenotype, however, in 20–30% of cases, the blasts have a lymphoid phenotype, mostly a B-cell phenotype. It is challenging to differentiate CML B-lymphoblastic phase (CML-BLP) from Ph + primary B-acute lymphoblastic leukemia (B-ALL) especially when the CML-BLP is the initial presentation of the disease, which is uncommon. We report here an unusual case of CML-BLP as an initial presentation of the disease without typical CML morphological findings. This case demonstrates diagnostic challenges and emphasizes the importance of an integrated approach using morphology, multiparametric flow cytometry, cytogenetic studies, and molecular studies to render an accurate diagnosis.

Cytogenetic aberrations in adult acute lymphoblastic leukemia-A population-based study

Cytogenetic aberrations are recognized as important prognostic factors in adult acute lymphoblastic leukemia (ALL), but studies seldom include elderly patients. From the population-based Swedish ALL Registry, we identified 728 patients aged 18-95 years, who were diagnosed with ALL 1997-2015 and had cytogenetic information. Registry data were complemented with original cytogenetic reports. BCR-ABL1 was the most recurrent aberration, with a frequency of 26%, with additional cytogenetic alterations in 64%. KTM2A rearrangement was the second most frequent aberration found in 7%. Low hypodiploidy-near triploidy and complex karyotype had negative impact, while t(1;19);TCF3-PBX1 showed positive impact on overall survival. However, after correction for age only complex karyotype remained significant.

DYRK1A regulates B cell acute lymphoblastic leukemia through phosphorylation of FOXO1 and STAT3

DYRK1A is a serine/threonine kinase encoded on human chromosome 21 (HSA21) that has been implicated in several pathologies of Down syndrome (DS), including cognitive deficits and Alzheimer's disease. Although children with DS are predisposed to developing leukemia, especially B cell acute lymphoblastic leukemia (B-ALL), the HSA21 genes that contribute to malignancies remain largely undefined. Here, we report that DYRK1A is overexpressed and required for B-ALL. Genetic and pharmacologic inhibition of DYRK1A decreased leukemic cell expansion and suppressed B-ALL development in vitro and in vivo. Furthermore, we found that FOXO1 and STAT3, transcription factors that are indispensable for B cell development, are critical substrates of DYRK1A. Loss of DYRK1A-mediated FOXO1 and STAT3 signaling disrupted DNA damage and ROS regulation, respectively, leading to preferential cell death in leukemic B cells. Thus, we reveal a DYRK1A/FOXO1/STAT3 axis that facilitates the development and maintenance of B-ALL.

Constitutive Activation of RAS/MAPK Pathway Cooperates with Trisomy 21 and Is Therapeutically Exploitable in Down Syndrome B-cell Leukemia

PURPOSE

Children with Down syndrome (constitutive trisomy 21) that develop acute lymphoblastic leukemia (DS-ALL) have a 3-fold increased likelihood of treatment-related mortality coupled with a higher cumulative incidence of relapse, compared with other children with B-cell acute lymphoblastic leukemia (B-ALL). This highlights the lack of suitable treatment for Down syndrome children with B-ALL.

EXPERIMENTAL DESIGN

To facilitate the translation of new therapeutic agents into clinical trials, we built the first preclinical cohort of patient-derived xenograft (PDX) models of DS-ALL, comprehensively characterized at the genetic and transcriptomic levels, and have proven its suitability for preclinical studies by assessing the efficacy of drug combination between the MEK inhibitor trametinib and conventional chemotherapy agents.

RESULTS

Whole-exome and RNA-sequencing experiments revealed a high incidence of somatic alterations leading to RAS/MAPK pathway activation in our cohort of DS-ALL, as well as in other pediatric B-ALL presenting somatic gain of the chromosome 21 (B-ALL+21). In murine and human B-cell precursors, activated KRAS^G12D functionally cooperates with trisomy 21 to deregulate transcriptional networks that promote increased proliferation and self renewal, as well as B-cell differentiation blockade. Moreover, we revealed that inhibition of RAS/MAPK pathway activation using the MEK1/2 inhibitor trametinib decreased leukemia burden in several PDX models of B-ALL+21, and enhanced survival of DS-ALL PDX in combination with conventional chemotherapy agents such as vincristine.

CONCLUSIONS

Altogether, using novel and suitable PDX models, this study indicates that RAS/MAPK pathway inhibition represents a promising strategy to improve the outcome of Down syndrome children with B-cell precursor leukemia.

Trisomy of a Down Syndrome Critical Region Globally Amplifies Transcription via HMGN1 Overexpression

Down syndrome (DS, trisomy 21) is associated with developmental abnormalities and increased leukemia risk. To reconcile chromatin alterations with transcriptome changes, we performed paired exogenous spike-in normalized RNA and chromatin immunoprecipitation sequencing in DS models. Absolute normalization unmasks global amplification of gene expression associated with trisomy 21. Overexpression of the nucleosome binding protein HMGN1 (encoded on chr21q22) recapitulates transcriptional changes seen with triplication of a Down syndrome critical region on distal chromosome 21, and HMGN1 is necessary for B cell phenotypes in DS models. Absolute exogenous-normalized chromatin immunoprecipitation sequencing (ChIP-Rx) also reveals a global increase in histone H3K27 acetylation caused by HMGN1. Transcriptional amplification downstream of HMGN1 is enriched for stage-specific programs of B cells and B cell acute lymphoblastic leukemia, dependent on the developmental cellular context. These data offer a mechanistic explanation for DS transcriptional patterns and suggest that further study of HMGN1 and RNA amplification in diverse DS phenotypes is warranted.

How trisomy 21 contributes to Down syndrome phenotypes, including increased leukemia risk, is not well understood. Mowery et al. use per-cell normalization approaches to reveal global transcriptional amplification in Down syndrome models. HMGN1 overexpression is sufficient to induce these alterations and promotes lineage-associated transcriptional programs, signaling, and B cell progenitor phenotypes.

Philadelphia chromosome-positive acute lymphoblastic leukemia at first relapse in the era of tyrosine kinase inhibitors

Despite the advances in the management of Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) with the introduction of tyrosine kinase inhibitors (TKIs), relapses remain challenging. We reviewed clinical data from adult patients with Ph + ALL who received frontline hyperCVAD chemotherapy with a TKI to determine their outcomes after first relapse. Patients with first morphological relapse after prior complete remission were evaluated for predictors of response and survival. For 57 of 233 (25%) patients, there was morphological relapse after a median of 15.9 months from first remission [range: 5.3-94]. The choice of salvage treatments was at the discretion of the treating physician. So, 43 (75%) patients received a TKI in combination with their salvage treatment. Second remission was achieved in 41 of 49 (84%) evaluable patients. Median relapse free survival (RFS) was 10.5 months [range, 0.2-81]. The 1-year and 2-year overall survival (OS) were 41% and 20% respectively. On multivariate analysis, only elevated LDH (units/L), the use of first-generation or no TKI at the time of first relapse and the achievement of a major molecular response (MMR) had a significant effect on OS (HR: 2.82, 95% CI:1.11-7.16, P = .029; HR = 2.39, 95% CI: 1.07,5.39, P = .034; HR = 0.39, 95% CI: 0.16-0.94, P = .03, respectively). Whereas, only achievement of MMR was significantly prognostic for RFS with a HR of 0.48 (95% CI: 0.23-0.98, P = .04). The OS and RFS were comparable between recipients and non-recipients of allogeneic hematopoietic stem cell transplantation (alloHSCT) at second remission, due to a higher non-relapse mortality (53%) seen in patients who underwent alloHSCT.

A near-haploid clone harboring a BCR/ABL1 gene fusion in an adult patient with newly diagnosed B-lymphoblastic leukemia

The detection of recurrent genetic abnormalities in B-lymphoblastic leukemia (B-ALL) is critical for risk stratification and therapy-related decisions. Near-haploidy (24-30 chromosomes), a subgroup of hypodiploidy (<46 chromosomes), and BCR/ABL1 gene fusions are both recurrent genetic abnormalities in B-ALL and are considered adverse prognostic findings, although outcomes in BCR/ABL1-positive patients have improved with tyrosine kinase inhibitor therapy. While near-haploid clones are primarily observed in children and rarely harbor structural abnormalities, BCR/ABL1-positive B-ALL is primarily observed in adults. Importantly, recurrent genetic abnormalities are considered mutually exclusive and rarely exist within the same neoplastic clone. We report only the second case to our knowledge of a near-haploid clone that harbors a BCR/ABL1 fusion in an adult with newly diagnosed B-ALL. Conventional chromosome studies revealed a near-haploid clone (27 chromosomes) along with a der(22)t(9;22)(q34.1;q11.2) in 17 of 20 metaphases analyzed. Our B-ALL fluorescence in situ hybridization (FISH) panel confirmed the BCR/ABL1 fusion and monosomies consistent with chromosome studies in approximately 95% of interphase nuclei. Moreover, no evidence of a "doubled" near-haploid clone was observed by chromosome or FISH studies. This highly unusual case illustrates that while rare, recurrent genetic abnormalities in B-ALL can exist within the same neoplastic clone.

Additional Cytogenetic Abnormalities with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia on Allogeneic Stem Cell Transplantation in the Tyrosine Kinase Inhibitor Era

Cytogenetic abnormalities are well known and powerful independent prognostic factors for various hematologic disorders. Although the combination of chemotherapy with tyrosine kinase inhibitor (TKI) is now considered the standard of care in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia, little is known about the impact of additional cytogenetic abnormalities (ACAs). Therefore, we retrospectively evaluated 1375 adult patients who underwent their first allogeneic hematopoietic stem cell transplantation in the TKI era. In this study, 224 patients had ACAs (16.3%). The ACAs that were seen in more than 20 cases (1.5%) were as follows: -7, der(22), der(9), +8, and +X. Overall survival at 4 years was 56.9% (95% confidence interval [CI], 49.4% to 63.7%) in the group with ACAs and 60.5% (95% CI, 57.3% to 63.5%) in the group without ACAs (P = .266). The cumulative incidence of relapse at 4 years was 28.9% (95% CI, 22.6% to 35.6%) in the group with ACAs and 21.9% (95% CI, 19.4% to 24.6%) in the group with Ph alone (P = .051). In multivariate analyses there were no statistically significant differences in the risk of overall mortality or risk of relapse between the groups with and without ACAs. In the subgroup analyses of specific ACAs, although the presence of +8 was associated with a higher relapse rate in univariate and multivariate analyses, no specific ACA was associated with poor overall survival. Further studies will be needed to verify the impact of specific ACAs on transplantation outcomes.

Dasatinib Plus Intensive Chemotherapy in Children, Adolescents, and Young Adults With Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia: Results of Children's Oncology Group Trial AALL0622

Purpose Addition of imatinib to intensive chemotherapy improved survival for children and young adults with Philadelphia chromosome-positive acute lymphoblastic leukemia. Compared with imatinib, dasatinib has increased potency, CNS penetration, and activity against imatinib-resistant clones. Patients and Methods Children's Oncology Group (COG) trial AALL0622 (Bristol Myers Squibb trial CA180-204) tested safety and feasibility of adding dasatinib to intensive chemotherapy starting at induction day 15 in patients with newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia age 1 to 30 years. Allogeneic hematopoietic stem-cell transplantation (HSCT) was recommended for patients at high risk based on slow response and for those with a matched family donor regardless of response after at least 11 weeks of therapy. Patients at standard risk based on rapid response received chemotherapy plus dasatinib for an additional 120 weeks. Patients with overt CNS leukemia received cranial irradiation. Results Sixty eligible patients were enrolled. Five-year overall (OS) and event-free survival rates (± standard deviations [SD]) were 86% ± 5% and 60% ± 7% overall, 87% ± 5% and 61% ± 7% for standard-risk patients (n = 48; 19% underwent HSCT), and 89% ± 13% and 67% ± 19% for high-risk patients (n = 9; 89% underwent HSCT), respectively. Five-year cumulative incidence (± SD) of CNS relapse was 15% ± 6%. Outcomes (± SDs) were similar to those in COG AALL0031, which used the same chemotherapy with continuous imatinib: 5-year OS of 81% ± 6% versus 86% ± 5% ( P = .63) and 5-year disease-free survival of 68% ± 7% versus 60% ± 7% ( P = 0.31) for AALL0031 versus AALL0622, respectively. IKZF1 deletions, present in 56% of tested patients, were associated with significantly inferior OS and event-free survival overall and in standard-risk patients. Conclusion Dasatinib was well tolerated with chemotherapy and provided outcomes similar to those with imatinib in COG AALL0031, where all patients received cranial irradiation. Our results support limiting HSCT to slow responders and suggest a potential role for transplantation in rapid responders with IKZF1 deletions.

B lymphoblastic leukemia/lymphoma: new insights into genetics, molecular aberrations, subclassification and targeted therapy

B lymphoblastic leukemia/lymphoma (B-ALL) is a clonal hematopoietic stem cell neoplasm derived from B-cell progenitors, which mostly occurs in children and adolescents and is regarded as one of top leading causes of death related to malignancies in this population. Despite the majority of patients with B-ALL have fairly good response to conventional chemotherapeutic interventions followed by hematopoietic stem cell transplant for the last decades, a subpopulation of patients show chemo-resistance and a high relapse rate. Adult B-ALL exhibits similar clinical course but worse prognosis in comparison to younger individuals. Ample evidences have shown that the clinical behavior, response rate and clinical outcome of B-ALL rely largely on its genetic and molecular profiles, such as the presence of BCR-ABL1 fusion gene which is an independent negative prognostic predictor. New B-ALL subtypes have been recognized with recurrent genetic abnormalities, including B-ALL with intrachromosomal amplification of chromosome 21 (iAMP21), B-ALL with translocations involving tyrosine kinases or cytokine receptors (“BCR-ABL1-like ALL”). Genome-wide genetic profiling studies on B-ALL have extended our understanding of genomic landscape of B-ALL, and genetic mutations involved in various key pathways have been illustrated. These include CRLF2 and PAX5 alterations, TP53, CREBBP and ERG mutations, characteristic genetic aberrations in BCR-ABL1-like B-ALL and others. The review further provides new insights into clinical implication of the genetic aberrations in regard to targeted therapy development.

Prognostic significance of recurrent additional chromosomal abnormalities in adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia

In Philadelphia (Ph) chromosome-positive acute lymphoblastic leukemia (ALL), additional chromosomal abnormalities (ACAs) are frequently observed. We investigated the cytogenetic characteristics and prognostic significance of ACAs in Ph-positive ALL. We reviewed the clinical data and bone marrow cytogenetic findings of 122 adult Ph-positive ALL patients. The ACAs were examined for partial or whole chromosomal gains or losses, and structural aberrations. The overall survival (OS) and disease-free survival (DFS) of patients who received hematopoietic cell transplantation were compared between the isolated Ph group and ACA group. ACAs were present in 73.0% of all patients. The recurrent ACAs were extra Ph (24.7%), 9/9p loss (20.2%), and 7/7p loss (19.1%). Complex karyotype was found in 28.1% of patients in the ACA group. Younger patients (19-30 years) in the ACA group showed the highest frequency of extra Ph (54%) compared to other age groups. The OS in the ACA group was significantly shorter than in the isolated Ph group. The presence of an extra Ph chromosome or 9/9p loss was significantly associated with shorter OS and DFS, whereas 7/7p loss and complex karyotype were not associated with poorer prognosis. We suggest that subclassification of ACAs could be applied to prognostic investigation of Ph-positive ALL.

[Clinical analysis of adult Philadelphia chromosome-positive acute lymphoblastic leukemia with p16 gene deletion]

Objective: To investigate the clinical implications of p16 gene deletion in adult Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL) . Methods: Retrospective analysis of clinical, immunophenotypic, cytogenetics, molecular characteristics and prognosis of 80 newly diagnosed Ph(+) ALL patients with p16 deletion. Results: Of 80 adult Ph(+) ALL, the prevalence of p16 gene deletion was 31.3%. p16 gene deletion carriers frequently accompanied with high WBC counts (WBC≥30×10(9)/L) and CD20 expression. The incidence of complex chromosome abnormality in p16 gene deletion group was higher than that in non-deletion group, with alternations in chromosome 7, 8, 19 and der (22) more frequently observed. There was no difference occurred between patients with or without p16 gene deletion in complete remission (CR) rate following induction chemotherapy combined with tyrosine kinase inhibitors (TKIs) . However, after three cycles of chemotherapy, the MMR and CMR rate in the p16 gene deletion group was lower than patients with wild-type p16 gene (P=0.034, P=0.036) . The p16 gene deletion patients showed no significant differences in MMR, CMR and relapse rate between Imatinib or Dasatinib plus chemotherapy (P>0.05) . Deletion of p16 gene was significantly associated with poor outcomes including worse overall survival (OS) (37.1% vs 54.1%, P=0.037) , lower disease free-survival (DFS) (12.4% vs 45.9%, P=0.026) , and increased cumulative incidence of relapse (P=0.033) . Among the 25 patients with p16 deletion, 14 underwent allo-HSCT and the median survival was 21 months, better than that of patients received chemotherapy alone (12 months) (P=0.030) . Conclusion: This study indicated that deletion of p16 was associated with poor prognosis in adult Ph(+) ALL, and the utility of second-generation TKI (Dasatinib) does not necessarily have an edge on efficacy over Imatinib, but allo-HSCT has the potential of elongating life expectancy. It is an important significance to define the status of p16 in Ph(+) ALL for predicting prognosis and guiding therapy decision-making.

Poor outcomes associated with +der(22)t(9;22) and -9/9p in patients with Philadelphia chromosome-positive acute lymphoblastic leukemia receiving chemotherapy plus a tyrosine kinase inhibitor

In patients with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) treated with chemotherapy plus a tyrosine kinase inhibitor (TKI), the prognostic impact of additional chromosomal abnormalities (ACAs) is not well-established. We evaluated the prognostic impact of individual ACAs in 152 patients with Ph+ ALL receiving first-line intensive chemotherapy plus either imatinib (n = 36), dasatinib (n = 74), or ponatinib (n = 42). ACAs were identified in 118 patients (78%). Compared to outcomes of patients without ACAs, ACAs were not associated with differences in either relapse-free survival (RFS; P = 0.42) or overall survival (OS; P = 0.51). When individual ACAs were evaluated, +der(22)t(9;22) and/or -9/9p in the absence of high hyperdiploidy (HeH) was present in 16% of patients and constituted a poor-risk ACA group. Patients with one or more poor-risk ACAs in the absence of HeH had significantly shorter RFS (5-year RFS rate 33% versus 59%, P = 0.01) and OS (5-year OS rate 24% versus 63%, P = 0.003). Poor-risk ACAs were prognostic in patients who received imatinib and dasatinib but not in those who received ponatinib. By multivariate analysis, this poor-risk ACA group was independently associated with worse RFS (HR 2.03 [95% CI 1.08-3.30], P = 0.03) and OS (HR 2.02 [95% CI 1.10-3.71], P = 0.02). Patients with Ph+ ALL who have +der(22)t(9;22) and/or -9/9p in the absence of HeH have relatively poor outcomes when treated with chemotherapy plus a TKI.

Sustaining integrating imatinib and interferon-α into maintenance therapy improves survival of patients with Philadelphia positive acute lymphoblastic leukemia ineligible for allogeneic stem cell transplantation

We report the clinical results of sustainedly integrating imatinib and interferon-α into maintenance therapy in the patients ineligible for allogeneic hematopoietic stem cell transplantation (allo-HSCT). Maintenance therapy lasted for 5 years with imatinib 400 mg daily, interferon-α 3 million units, 2∼3 doses per week, and chemotherapy including vindesine and dexamethasone scheduled monthly in first year, once every 2 months in second year, and once every 3 months in third year. The chemotherapy was discontinued after 3 years and the imatinib and interferon-α continued for another 2 years. For 41 patients without allo-HSCT with a median follow-up of 32 months, the 3-year DFS and OS were 42.7  ± 8.6% and 57.9  ± 8.4%, respectively. Our study suggests that sustaining maintenance with low-dose chemotherapy, imatinib and interferon-α improved survival of adult Philadelphia-positive acute lymphoblastic leukemia (Ph + ALL) patients ineligible for allo-HSCT, and even provided an opportunity for cure. BCR/ABL persistent negativity at 6 and 9 months may have benefit to choose suitable patients for the imatinib/interferon-α maintenance strategy.

Impact of Additional Cytogenetic Abnormalities in Adults with Philadelphia Chromosome-Positive Acute Lymphoblastic Leukemia Undergoing Allogeneic Hematopoietic Cell Transplantation

The occurrence of additional cytogenetic abnormalities (ACAs) is common in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) but is of unknown significance in the tyrosine kinase inhibitor (TKI) era. We retrospectively analyzed data from a consecutive case series of adults with Ph+ ALL who had undergone allogeneic hematopoietic cell transplantation (alloHCT) at City of Hope between 2003 and 2014. Among 130 adults with Ph+ ALL who had TKI therapy before alloHCT, 78 patients had available data on conventional cytogenetics at diagnosis and were eligible for outcomes analysis. ACAs were observed in 41 patients (53%). There were no statistically significant differences in median age, median initial WBC count, post-HCT TKI maintenance, or disease status at the time of transplant between the Ph-only and ACA cohorts; however, the Ph-only cohort had a higher rate of minimal residual disease positivity at the time of HCT. Three-year leukemia-free survival (79.8% versus 39.5%, P = .01) and 3-year overall survival (83% versus 45.6%, P = .02) were superior in the Ph-only cohort compared with the ACA cohort, respectively. Monosomy 7 was the most common additional aberration observed in our ACA cohort (n = 12). Thus, when TKI therapy and alloHCT are used as part of adult Ph+ ALL therapy, the presence of ACAs appears to have a significant deleterious effect on outcomes post-HCT.

An adult B-cell precursor acute lymphoblastic leukemia with multiple secondary cytogenetic aberrations

BACKGROUND

We report a clinically diagnosed acute lymphoblastic leukemia (ALL) with yet unreported secondary chromosomal aberrations.

RESULTS

A complete cytogenetic and molecular cytogenetic analysis, using GTG banding, fluorescence in situ hybridization (FISH) and array-proven multicolor banding (aMCB), for a female patient with clinically diagnosed ALL and immunophenotypically confirmed pre-B ALL (FAB classifications), revealed the presence of a complex structural rearrangement, der (2) (20qter- > 20q13.33::2q21- > 2p14::2q21 > 2qter) along with t (9;22) (q34;q11), t (12;14) (q12;p12) and a monosomy of chromosome 7.

CONCLUSIONS

Molecular cytogenetic studies are suited best for identification and characterization of chromosomal rearrangements in acute leukemia. Single case reports as well as large scale studies are necessary to provide further insights in karyotypic changes taking place in human malignancies.

Triplication of a 21q22 region contributes to B cell transformation through HMGN1 overexpression and loss of histone H3 Lys27 trimethylation

Down syndrome confers a 20-fold increased risk of B cell acute lymphoblastic leukemia (B-ALL)¹ and polysomy 21 is the most frequent somatic aneuploidy amongst all B-ALLs². Yet, the mechanistic links between chr.21 triplication and B-ALL remain undefined. Here we show that germline triplication of only 31 genes orthologous to human chr.21q22 confers murine progenitor B cell self-renewal in vitro, maturation defects in vivo, and B-ALL with either BCR-ABL or CRLF2 with activated JAK2. Chr.21q22 triplication suppresses H3K27me3 in progenitor B cells and B-ALLs, and “bivalent” genes with both H3K27me3 and H3K4me3 at their promoters in wild-type progenitor B cells are preferentially overexpressed in triplicated cells. Strikingly, human B-ALLs with polysomy 21 are distinguished by their overexpression of genes marked with H3K27me3 in multiple cell types. Finally, overexpression of HMGN1, a nucleosome remodeling protein encoded on chr.21q22^3–5, suppresses H3K27me3 and promotes both B cell proliferation in vitro and B-ALL in vivo.

Current and future management of Ph/BCR-ABL positive ALL

Following the introduction of targeted therapy with tyrosine kinase inhibitors (TKI) at the beginning of the past decade, the outcome of patients with Philadelphia-chromosome positive acute lymphoblastic leukemia (Ph+ ALL) has dramatically improved. Presently, the use of refined programs with first/second generation TKI's and chemotherapy together with allogeneic stem cell transplantation allow up to 50% of all patients to be cured. Further progress is expected with the new TKI ponatinib, overcoming resistance caused by T315I point mutation, other targeted therapies, autologous transplantation in molecularly negative patients, therapeutic monoclonal antibodies like inotuzumab ozogamicin and blinatumomab, and chimeric antigen receptor-modified T cells. Ph+ ALL could become curable in the near future even without allogeneic stem cell transplantation, minimizing the risk of therapy-related death and improving greatly the quality of patients' life.

A target-disease network model of second-generation BCR-ABL inhibitor action in Ph+ ALL

Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) is in part driven by the tyrosine kinase bcr-abl, but imatinib does not produce long-term remission. Therefore, second-generation ABL inhibitors are currently in clinical investigation. Considering different target specificities and the pronounced genetic heterogeneity of Ph+ ALL, which contributes to the aggressiveness of the disease, drug candidates should be evaluated with regard to their effects on the entire Ph+ ALL-specific signaling network. Here, we applied an integrated experimental and computational approach that allowed us to estimate the differential impact of the bcr-abl inhibitors nilotinib, dasatinib, Bosutinib and Bafetinib. First, we determined drug-protein interactions in Ph+ ALL cell lines by chemical proteomics. We then mapped those interactions along with known genetic lesions onto public protein-protein interactions. Computation of global scores through correlation of target affinity, network topology, and distance to disease-relevant nodes assigned the highest impact to dasatinib, which was subsequently confirmed by proliferation assays. In future, combination of patient-specific genomic information with detailed drug target knowledge and network-based computational analysis should allow for an accurate and individualized prediction of therapy.

Autologous transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia achieves outcomes similar to allogeneic transplantation: results of CALGB Study 10001 (Alliance)

Allogeneic stem cell transplantation is the standard approach to Philadelphia chromosome positive acute lymphoblastic leukemia. We hypothesized that imatinib plus sequential chemotherapy will result in significant leukemia cell cytoreduction in patients with Philadelphia chromosome positive acute lymphoblastic leukemia, allowing collection of normal hematopoietic stem cells uncontaminated by residual BCR/ABL1(+) lymphoblasts and thus reduce the likelihood of relapse after autologous stem cell transplantation for patients under 60 years of age without sibling donors. We enrolled 58 patients; 19 underwent autologous and 15 underwent allogeneic stem cell transplantation on study. Imatinib plus sequential chemotherapy resulted in reverse-transcriptase polymerase chain reaction-negative stem cells in 9 patients and remained minimally positive in 4 (6 were not evaluable). Overall survival (median 6.0 years vs. not reached) and disease-free survival (median 3.5 vs. 4.1 years) were similar between those who underwent autologous and those who underwent allogeneic stem cell transplantation. We conclude that autologous stem cell transplantation represents a safe and effective alternative for allogeneic stem cell transplantation in Philadelphia chromosome positive acute lymphoblastic leukemia patients without sibling donors (clinicaltrials.gov identifier:00039377).

High modal number and triple trisomies are highly correlated favorable factors in childhood B-cell precursor high hyperdiploid acute lymphoblastic leukemia treated according to the NOPHO ALL 1992/2000 protocols

Between 1992 and 2008, 713 high hyperdiploid acute lymphoblastic leukemias in children aged 1-15 years were diagnosed and treated according to the Nordic Society for Pediatric Hematology and Oncology acute lymphoblastic leukemia 1992/2000 protocols. Twenty (2.8%) harbored t(1;19), t(9;22), der(11q23), or t(12;21). The median age of patients with "classic" high hyperdiploidy was lower than that of patients with translocation-positive high hyperdiploidy (P<0.001). Cases with triple trisomies (+4, +10, +17), comprising 50%, had higher modal numbers than the triple trisomy-negative cases (P<0.0001). The probabilities of event-free survival and overall survival were lower for those with white blood cell counts ≥ 50 × 10(9)/L (P=0.017/P=0.009), ≥ 5% bone marrow blasts at day 29 (P=0.001/0.002), and for high-risk patients (P<0.001/P=0.003), whereas event-free, but not overall, survival, was higher for cases with gains of chromosomes 4 (P<0.0001), 6 (P<0.003), 17 (P=0.010), 18 (P=0.049), and 22 (P=0.040), triple trisomies (P=0.002), and modal numbers >53/55 (P=0.020/0.024). In multivariate analyses, modal number and triple trisomies were significantly associated with superior event-free survival in separate analyses with age and white blood cell counts. When including both modal numbers and triple trisomies, only low white blood cell counts were significantly associated with superior event-free survival (P=0.009). We conclude that high modal chromosome numbers and triple trisomies are highly correlated prognostic factors and that these two parameters identify the same subgroup of patients characterized by a particularly favorable outcome.

IK6 isoform with associated cytogenetic and molecular abnormalities in Chinese patients with Philadelphia chromosome-positive adult acute lymphoblastic leukemia

The IK6 isoform plays an important role in Philadelphia chromosome-positive adult acute lymphoblastic leukemia (Ph + ALL). This study was designed to monitor the expression of the IK6 isoform with associated cytogenetic and molecular abnormalities. The IK6 isoform, cytogenetic and molecular abnormalities were detected in 100 Chinese patients with de novo Ph+ adult ALL. Expression levels of the IK6 isoform and BCR-ABL1 transcripts were monitored during treatment. BCR-ABL1 mutation was identified in 45 paired samples. Strong correlations were found between the expression status of the IK6 isoform and blast cells, additional cytogenetic abnormalities, BCR-ABL1 transcripts, increased risk of relapse, shorter relapse-free survival and overall survival at diagnosis. Higher frequencies of single IK6 expression and ABL mutation, including the types and shifts thereof, were confirmed in relapsed patients. Furthermore, expression of the IK6 isoform was dynamically consistent with BCR-ABL1 transcript levels during treatment in the single expression group, whereas no such correlation was observed in the co-expression group. The expression pattern of the IK6 isoform was altered in three patients from the co-expression group. The findings of this study in Chinese patients with Ph+ adult ALL exhibit some discrepancies with data reported in other countries, thereby enhancing current knowledge on the therapeutic response and prognosis of this disease.

CUX1 is a haploinsufficient tumor suppressor gene on chromosome 7 frequently inactivated in acute myeloid leukemia

Loss of chromosome 7 and del(7q) [-7/del(7q)] are recurring cytogenetic abnormalities in hematologic malignancies, including acute myeloid leukemia and therapy-related myeloid neoplasms, and associated with an adverse prognosis. Despite intensive effort by many laboratories, the putative myeloid tumor suppressor(s) on chromosome 7 has not yet been identified.We performed transcriptome sequencing and SNP array analysis on de novo and therapy-related myeloid neoplasms, half with -7/del(7q). We identified a 2.17-Mb commonly deleted segment on chromosome band 7q22.1 containing CUX1, a gene encoding a homeodomain-containing transcription factor. In 1 case, CUX1 was disrupted by a translocation, resulting in a loss-of-function RNA fusion transcript. CUX1 was the most significantly differentially expressed gene within the commonly deleted segment and was expressed at haploinsufficient levels in -7/del(7q) leukemias. Haploinsufficiency of the highly conserved ortholog, cut, led to hemocyte overgrowth and tumor formation in Drosophila melanogaster. Similarly, haploinsufficiency of CUX1 gave human hematopoietic cells a significant engraftment advantage on transplantation into immunodeficient mice. Within the RNA-sequencing data, we identified a CUX1-associated cell cycle transcriptional gene signature, suggesting that CUX1 exerts tumor suppressor activity by regulating proliferative genes. These data identify CUX1 as a conserved, haploinsufficient tumor suppressor frequently deleted in myeloid neoplasms.

Prognostic significance of immunophenotypic and karyotypic features of Philadelphia positive B-lymphoblastic leukemia in the era of tyrosine kinase inhibitors

BACKGROUND

Philadelphia chromosome (Ph)-positive B-lymphoblastic leukemia exhibits immunophenotypic, karyotypic, and molecular genetic heterogeneity. The prognostic significance of these parameters was assessed in the context of intensive tyrosine kinase inhibitor (TKI)-based chemotherapy.

METHODS

The authors studied 65 adult patients with Ph-positive acute lymphoblastic leukemia (ALL) who received treatment with TKI-based therapy, correlated their clinicopathologic heterogeneity with patient outcome, and compared the findings with those from 60 adult patients with diploid B-cell ALL who received similar chemotherapy without a TKI.

RESULTS

Ph-positive ALL was associated with older age (P = .01), the common-B immunophenotype characterized by a greater frequency of CD13 (alanine aminopeptidase) coexpression (P = .004), CD66c (carcinoembryonic antigen-related cell adhesion molecule 3) expression (P = .007), and CD25 (interleukin-2 receptor alpha chain) expression (P < .001) and with a lower frequency of CD15 (3-fucosyl-N-acetyl-lactosamine) expression (P < .001). Conventional karyotypic analyses indicated that the Ph chromosome was the sole abnormality in 19 patients (30%), was present with other aberrancies in 43 patients (65%), and was absent (detectable only by fluorescence in situ hybridization [FISH] or quantitative reverse transcriptase-polymerase chain reaction [RT-PCR] analysis) in 3 patients (5%). The presence of the breakpoint cluster region-v-Abelson murine leukemia viral oncogene homolog fusion gene (BCR-ABL) was confirmed in all patients by FISH or RT-PCR (the 190-kDa protein [p190] construct was present in 49 patients [77%], and the p210 fusion transcript construct was present in 15 patients [23%]). The presence of a supernumerary Ph chromosome was correlated with a higher incidence of CD20 (B-lymphocyte antigen, nonglycosylated phosphoprotein) expression (P < .001), whereas the p210 construct was correlated with aberrant CD25 expression (P = .05). Outcomes were not influenced by the degree of karyotypic complexity (including the presence or absence of a supernumerary Ph chromosome), CD20 expression, or myeloid antigen expression (CD13, CD33 [myeloid lineage transmembrane receptor], CD66c). CD25 expression was associated with inferior survival in univariate analysis (P = .051) but not in multivariate analysis (P = .092).

CONCLUSIONS

In the context of intensive, TKI-based chemotherapy, the immunophenotypic, karyotypic, and molecular heterogeneity of Ph-positive ALL no longer influences outcome.

Philadelphia chromosome-positive acute lymphoblastic leukemia: current treatment and future perspectives

The Philadelphia chromosome (Ph) is the most common cytogenetic abnormality associated with adult acute lymphoblastic leukemia (ALL). Before the advent of tyrosine kinase inhibitors (TKIs), Ph-positive ALL carried a dismal prognosis and was characterized by a poor response to most chemotherapy combinations, short remission durations, and poor survival rates. Outcomes for patients with Ph-positive ALL improved substantially with the introduction of TKIs, and the TKI imatinib induced complete remissions in >95% of patients with newly diagnosed Ph-positive ALL when it was combined with chemotherapy. However, imatinib resistance remains a problem in a substantial proportion of patients with Ph-positive ALL, and multiple molecular mechanisms that contribute to imatinib resistance have been identified. Second-generation TKIs (eg, dasatinib and nilotinib) have demonstrated promising efficacy in the treatment of imatinib-resistant, Ph-positive ALL. Future strategies for Ph-positive ALL include novel, molecularly targeted treatment modalities and further evaluations of TKIs in combination with established antileukemic agents. For this article, the authors reviewed past, current, and future treatment approaches for adult and elderly patients with Ph-positive ALL with a focus on TKIs and combined chemotherapeutic regimens.

How I treat Philadelphia chromosome–positive acute lymphoblastic leukemia

The Philadelphia chromosome is present in approximately 20% to 30% of adults with acute lymphoblastic leukemia (ALL). The poor prognosis of this relatively uncommon acute leukemia has led to the rapid adoption of treatment strategies such as unrelated donor hematopoietic stem cell transplant and tyrosine kinase inhibitors into clinical practice, despite a relative paucity of randomized clinical trials. Recently, there has been a surge of interest in the underlying biology of ALL. In combination with an accumulation of more mature clinical study data in Philadelphia-positive ALL, it is increasingly possible to make more rational and informed treatment choices for patients of all ages. In this article, I review available data and indicate how I personally interpret current evidence to make pragmatic treatment choices with my patients, outside of clinical trials. My strongest recommendation is that all physicians who are treating this rare disease actively seek appropriate clinical trials for their patients wherever possible.

Cytogenetics and molecular genetics of acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is a malignant disease that often features nonrandom numerical or structural chromosome aberrations that can be detected microscopically. The application of contemporary genome-wide molecular analyses is revealing additional genetic alterations that are not detectable cytogenetically. This article describes the cytogenetic methodology and summarizes major cytogenetic findings and their clinical relevance in ALL. The article provides a review of modern molecular techniques and their application in the research on the genetics and epigenetics of ALL.

Adult precursor B lymphoblastic leukemia in Shanghai, China: characterization of phenotype, cytogenetics and outcome for 137 consecutive cases

Acute lymphoblastic leukemia (ALL) accounts for 20-30% of adult leukemia in the West. However, detailed studies of B-cell-specific ALL in adult Asian populations are lacking. We diagnosed and characterized 137 consecutive cases of precursor B lymphoblastic leukemia (precursor B-cell ALL) presented to our laboratory in Shanghai using the WHO 2001 classification system. Patient clinical, phenotypic and cytogenetic characteristics were correlated with outcome. In contrast to Western studies, females (71) outnumbered males (66) partly due to an increased prevalence of the CD10- pro B-cell phenotype. Females with a CD10- pro B-cell phenotype exhibited significantly better overall survival than males. The most common cytogenetic abnormality was the Philadelphia chromosome (PH/BCR/ABL) which was found in approximately 37% of the cases. Cases of precursor B cell ALL lacking the PH/BCR/ABL genotype exhibited a pronounced age-dependent, gender prevalence with a modal age in the sixth decade for females compared to the second decade for males. These findings suggest significant geographic heterogeneity in precursor B-cell ALL which may be of both etiological and therapeutic significance.

Additional chromosomal abnormalities and their prognostic significance in adult Philadelphia-positive acute lymphoblastic leukemia: with or without imatinib in chemotherapy

The study analyzed the characteristics and prognostic significance of additional chromosomal abnormalities in 110 Chinese adults with Philadelphia chromosome-positive (Ph-positive) acute lymphoblastic leukemia (ALL). Secondary aberrations were present in 60.9% of the cases. All chromosomes were involved in secondary aberrations, and chromosomes 9, 7, 21, 18, and 14 were most frequently abnormal. Fifty of 110 patients (45.5%) had at least one normal metaphase cell in their chromosome preparations at diagnosis. Patients with additional aberrations had shorter disease-free survival (DFS) and overall survival (OS) in chemotherapy combined with imatinib (ICT) group and only shorter DFS in conventional chemotherapy (CT) group. The existence of normal metaphase cells was associated with a superior survival in CT group, but not in ICT group. Patients with loss of chromosomes 7, 7p, 9, and 9p had inferior outcome compared to patients with other secondary aberrations and those without secondary aberrations, in both CT and ICT group.

Prospective outcome data on 267 unselected adult patients with Philadelphia chromosome-positive acute lymphoblastic leukemia confirms superiority of allogeneic transplantation over chemotherapy in the pre-imatinib era: results from the International ALL Trial MRC UKALLXII/ECOG2993

Prospective data on the value of allogeneic hematopoietic stem cell transplantation (alloHSCT) in Philadelphia chromosome-positive (Ph(+)) acute lymphoblastic leukemia (ALL) are limited. The UKALLXII/ECOG 2993 study evaluated the outcome of assigning alloHSCT with a sibling (sib) or matched unrelated donor (MUD) to patients younger than 55 years of age achieving complete remission (CR). The CR rate of 267 patients, median age 40, was 82%. Twenty-eight percent of patients proceeded to alloHSCT in first CR. Age older than 55 years or a pre-HSCT event were the most common reasons for failure to progress to alloHSCT. At 5 years, overall survival (OS) was 44% after sib alloHSCT, 36% after MUD alloHSCT, and 19% after chemotherapy. After adjustment for sex, age, and white blood count and excluding chemotherapy-treated patients who relapsed or died before the median time to alloHSCT, only relapse-free survival remained significantly superior in the alloHSCT group (odds ratio 0.31, 95% confidence interval 0.16-0.61). An intention-to-treat analysis, using the availability or not of a matched sibling donor, showed 5-year OS to be nonsignificantly better at 34% with a donor versus 25% with no donor. This prospective trial in adult Ph(+) ALL indicates a modest but significant benefit to alloHSCT. This trial has been registered with clinicaltrials.gov under identifier NCT00002514 and as ISRCTN77346223.

Methylation status of Wnt signaling pathway genes affects the clinical outcome of Philadelphia-positive acute lymphoblastic leukemia

The clinical significance of aberrant promoter methylation of the canonical Wnt pathway antagonist genes (sFRP1, sFRP2, sFRP4, sFRP5, Wif1, Dkk3, and Hdpr1) and also putative tumor-suppressor gene Wnt5a, belonging to the non-canonical Wnt signaling pathway, was investigated in a large series of 75 patients with Philadelphia chromosome-positive acute lymphoblastic leukemia by methylation-specific polymerase chain reaction. At least one methylated gene was observed in cells from 66% (49/75) of patients (methylated group). Disease-free survival and overall survival at 9 years were 51 and 40%, respectively, for the unmethylated group and 3 and 2%, respectively, for the methylated group (both P < 0.0001). Multivariate analysis demonstrated that the Wnt methylation profile was an independent prognostic factor predicting disease-free survival (P = 0.007) and overall survival (P = 0.039). Abnormal DNA methylation of promoter-associated CpG islands in the Wnt signaling pathway is very common in Philadelphia chromosome-positive acute lymphoblastic leukemia and potentially defines subgroups with distinct clinical characteristics.

[A Case of Acute Lymphoblastic Leukemia with ider(9)(q10)t(9;22)(q34;q11.2).]

ider(9)(q10)t(9;22)(q34;q11.2) is an isochromosome for the long arm of a derivative chromosome 9 generated by a t(9;22), resulting from the deletion of the short arm of chromosome 9. It is known to be rarely observed in acute lymphoblastic leukemia (ALL) or lymphoblastic crisis transformed from chronic myelogenous leukemia. We herein describe a 26-year-old female patient with precursor B-cell ALL, cytogenetically characterized by ider(9)(q10)t(9;22). Fluorescence in situ hybridization analysis showed two ABL-BCR fusion signals on the derivative chromosome 9 and one BCR-ABL fusion signal on the derivative chromosome 22. Although a t(9;22) and a deletion of the short arm of chromosome 9 are known to be associated with a poor prognostic factor in acute lymphoblastic leukemia, a larger study is needed to determine the prognosis of ider(9)(q10)t(9;22) cases.