DoesBCR/ABL1positive Acute Myeloid Leukaemia Exist?

Imatinib with intensive chemotherapy in AML with t(9;22)(q34.1;q11.2)/BCR::ABL1. A DATAML registry study

Acute myeloid leukemia (AML) with t(9;22) (q34.1; q11.2)/BCR::ABL1, a distinct entity within the group of AML with defining genetic abnormalities, belong to the adverse-risk group of the 2022 ELN classification. However, there is little data on outcome since the era of tyrosine kinase inhibitors. Among 5819 AML cases included in the DATAML registry, 20 patients with de novo BCR::ABL1+AML (0.3%) were identified. Eighteen patients treated with standard induction chemotherapy were analyzed in this study. Imatinib was added to chemotherapy in 16 patients. The female-to-male ratio was 1.25 and median age was 54 years. The t(9;22) translocation was the sole chromosomal abnormality in 12 patients. Main gene mutations detected by NGS were ASXL1, RUNX1 and NPM1. Compared with patients with myeloid blast phase of chronic myeloid leukemia (CML-BP), de novo BCR::ABL1+AML had higher WBC, fewer additional chromosomal abnormalities, lower CD36 or CD7 expression and no ABL1 mutations. Seventeen patients (94.4%) achieved complete remission (CR) or CR with incomplete hematologic recovery. Twelve patients were allografted in first remission. With a median follow-up of 6.3 years, the median OS was not reached and 2-year OS was 77% (95% CI: 50-91). Four out of five patients who were not transplanted did not relapse. Comparison of BCR::ABL1+AML, CML-BP, 2017 ELN intermediate (n = 643) and adverse-risk patients (n = 863) showed that patients with BCR::ABL1+AML had a significant better outcome than intermediate and adverse-risk patients. BCR::ABL1+AML patients treated with imatinib and intensive chemotherapy should not be included in the adverse-risk group of current AML classifications.

Precision Medicine Approaches in Acute Myeloid Leukemia with Adverse Genetics

The treatment of acute myeloid leukemia (AML) with adverse genetics remains unsatisfactory, with very low response rates to standard chemotherapy and shorter durations of remission commonly observed in these patients. The complex biology of AML with adverse genetics is continuously evolving. Herein, we discuss recent advances in the field focusing on the contribution of molecular drivers of leukemia biogenesis and evolution and on the alterations of the immune system that can be exploited with immune-based therapeutic strategies. We focus on the biological rationales for combining targeted therapy and immunotherapy, which are currently being investigated in ongoing trials, and could hopefully ameliorate the poor outcomes of patients affected by AML with adverse genetics.

The impact of the BCR-ABL oncogene in the pathology and treatment of chronic myeloid leukemia

Chronic Myeloid Leukemia (CML) is characterized by chromosomal aberrations involving the fusion of the BCR and ABL genes on chromosome 22, resulting from a reciprocal translocation between chromosomes 9 and 22. This fusion gives rise to the oncogenic BCR-ABL, an aberrant tyrosine kinase identified as Abl protein. The Abl protein intricately regulates the cell cycle by phosphorylating protein tyrosine residues through diverse signaling pathways. In CML, the BCR-ABL fusion protein disrupts the first exon of Abl, leading to sustained activation of tyrosine kinase and resistance to deactivation mechanisms. Pharmacological interventions, such as imatinib, effectively target BCR-ABL's tyrosine kinase activity by binding near the active site, disrupting ATP binding, and inhibiting downstream protein phosphorylation. Nevertheless, the emergence of resistance, often attributed to cap structure mutations, poses a challenge to imatinib efficacy. Current research endeavours are directed towards overcoming resistance and investigating innovative therapeutic strategies. This article offers a comprehensive analysis of the structural attributes of BCR-ABL, emphasizing its pivotal role as a biomarker and therapeutic target in CML. It underscores the imperative for ongoing research to refine treatment modalities and enhance overall outcomes in managing CML.

[Clinical analysis of allogeneic hematopoietic stem cell transplantation for seven cases of acute myeloid leukemia with BCR::ABL1 fusion]

Objective: To explore the efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in acute myeloid leukemia (AML) patients with BCR::ABL1 fusion. Methods: The clinical data of seven AML patients with BCR::ABL1 fusion from November 2012 to January 2022 were retrospectively analyzed, and their survival status was followed up. Results: The median age of patients at the time of diagnosis was 35 years. Four cases (57.1%) were diagnosed with high leukocyte counts. All cases were assayed as BCR::ABL1 positive and accompanied by four types of gene mutations (NPM1, RUNX1, ASXL1, PHF6) . Seven patients received tyrosine kinase inhibitor (TKI) combined with induction chemotherapy and bridged to allo-HSCT, and six patients received maintenance therapy with TKI. Before allo-HSCT, six patients achieved complete remission, and four patients achieved complete molecular remission (CMR) . After allo-HSCT, the three remaining cases also achieved CMR. All patients were in remission post-allo-HSCT. One case died of infection, and the remaining cases survived without relapse. The 3-year cumulative overall survival rate was (80.0±17.9) %. Conclusions: TKI combined with traditional chemotherapy could achieve a high response rate in AML patients with BCR::ABL1 fusion. In addition, allo-HSCT could enhance the molecular response rate. Maintenance therapy post-HSCT with TKI could improve prognosis.

An interesting case of chronic myeloid leukemia (CML) with T315I mutation raising suspicion of de novo AML, a diagnostic conundrum

Chronic myeloid leukemia (CML) is a myeloproliferative disorder due to translocation between chromosomes (9, 22), known as the "Philadelphia chromosome." In 2016, the World health organization (WHO) introduced a new clinical entity of de novo acute myeloid leukemia (AML). Both diseases share some commonalities, therefore, create a challenge to diagnose.

Epigenomic machinery regulating pediatric AML: clonal expansion mechanisms, therapies, and future perspectives

Acute myeloid leukemia (AML) is a heterogeneous disease with a genetic, epigenetic, and transcriptional etiology mainly presenting somatic and germline abnormalities. AML incidence rises with age but can also occur during childhood. Pediatric AML (pAML) accounts for 15-20% of all pediatric leukemias and differs considerably from adult AML. Next-generation sequencing technologies have enabled the research community to "paint" the genomic and epigenomic landscape in order to identify pathology-associated mutations and other prognostic biomarkers in pAML. Although current treatments have improved the prognosis for pAML, chemoresistance, recurrence, and refractory disease remain major challenges. In particular, pAML relapse is commonly caused by leukemia stem cells that resist therapy. Marked patient-to-patient heterogeneity is likely the primary reason why the same treatment is successful for some patients but, at best, only partially effective for others. Accumulating evidence indicates that patient-specific clonal composition impinges significantly on cellular processes, such as gene regulation and metabolism. Although our understanding of metabolism in pAML is still in its infancy, greater insights into these processes and their (epigenetic) modulation may pave the way toward novel treatment options. In this review, we summarize current knowledge on the function of genetic and epigenetic (mis)regulation in pAML, including metabolic features observed in the disease. Specifically, we describe how (epi)genetic machinery can affect chromatin status during hematopoiesis, leading to an altered metabolic profile, and focus on the potential value of targeting epigenetic abnormalities in precision and combination therapy for pAML. We also discuss the possibility of using alternative epidrug-based therapeutic approaches that are already in clinical practice, either alone as adjuvant treatments and/or in combination with other drugs.

Management of children and adolescents with chronic myeloid leukemia in blast phase: International pediatric CML expert panel recommendations

Treatment of chronic myeloid leukemia has improved significantly with the introduction of tyrosine kinase inhibitors (TKIs), and treatment guidelines based on numerous clinical trials are available for chronic phase disease. However for CML in the blast phase (CML-BP), prognosis remains poor and treatment options are much more limited. The spectrum of treatment strategies for children and adolescents with CML-BP has largely evolved empirically and includes treatment principles derived from adult CML-BP and pediatric acute leukemia. Given this heterogeneity of treatment approaches, we formed an international panel of pediatric CML experts to develop recommendations for consistent therapy in children and adolescents with this high-risk disease based on the current literature and national standards. Recommendations include detailed information on initial diagnosis and treatment monitoring, differentiation from Philadelphia-positive acute leukemia, subtype-specific selection of induction therapy, and combination with tyrosine kinase inhibitors. Given that allogeneic hematopoietic stem cell transplantation currently remains the primary curative intervention for CML-BP, we also provide recommendations for the timing of transplantation, donor and graft selection, selection of a conditioning regimen and prophylaxis for graft-versus-host disease, post-transplant TKI therapy, and management of molecular relapse. Management according to the treatment recommendations presented here is intended to provide the basis for the design of future prospective clinical trials to improve outcomes for this challenging disease.

Comparative Expression Analysis of Breakpoint Cluster Region-Abelson Oncogene in Leukemia Patients

Leukemia is a proliferative disorder of myeloid and lymphoid cells that may lead to death. Different types of leukemia have been reported, and several genetic and environmental factors are involved in their development. The Philadelphia chromosome causes the most common mutation known as breakpoint cluster region-Abelson oncogene (BCR-ABL1), which shows abnormal protein tyrosine kinase (PTK) activity. Basically, this activity is accountable for activating multiple pathways, including the inhibition of cell differentiation, controlled proliferation, and cell death. As a result of the absence of kinase activity, this mutation leads to the uncontrolled proliferation of leukocytes, causing chronic myeloid leukemia (CML), acute myeloid leukemia (AML), acute lymphoid leukemia (ALL), and chronic lymphocytic leukemia (CLL). This study aimed to evaluate the level of BCR-ABL1 expression in patients with these types of leukemias through qPCR. In brief, PBMCs were isolated from blood samples of patients, RNA was extracted from PBMCs, cDNA was synthesized, and the transcript levels of BCR-ABL1 in patients with each type of leukemia were determined by qPCR. The clinical, demographical, and experimental data were analyzed among CML, AML, and ALL patients. Results: The BCR-ABL1 expression levels are variable in all studied groups and are 90, 30-35, and 1-2.5% in CML, ALL, and AML, respectively. Demographic characteristics such as gender, BMI, age, family history, and clinical parameters along with CBC are also associated with the prevalence and diagnosis of leukemia. In a comparative expression analysis, the expression of BCR-ABL1 is onefold high in AML, but four- and sevenfold high in ALL and CML, respectively, as compared with normal levels. Conclusions: In this study, a significant difference was observed in the expression levels of BCR-ABL1 between CML (p = 0.0043) and ALL (p = 0.0006) and between CML and AML groups, and a high expression of BCR-ABL1 was noted in CML as compared with ALL and AML.

Molecular genetic characterization of Philadelphia chromosome-positive acute myeloid leukemia

BACKGROUND

Philadelphia chromosome-positive acute myeloid leukemia (Ph+ AML) is a provisional disease entity in the 2016 WHO classification, while its genetic profile of Ph+ AML remains poorly defined. In addition, the differentiating features of Ph+ AML and chronic myeloid leukemia in myeloid blast crisis (CML-MBC) remain controversial.

METHODS

We conducted a retrospective study of 15 Ph+ AML patients to compare their clinical and laboratory profiles with 27 CML-MBC patients.

RESULTS

Compared to CML-MBC, Ph+ AML patients presented with significantly higher peripheral WBC count and bone marrow blast percentage. The immunophenotypic profiles were largely similar between Ph+ AML and CML-MBC, except for CD4 expression, which was significantly enriched in CML-MBC. Ph+ AML patients less frequently harboured co-occurring additional cytogenetic abnormalities (ACA) compared to CML-MBC, and trisomy 19 (23%) and IDH1/2 (46%) were the most common ACA and mutated genes in Ph+ AML, respectively. Overall survival (OS) did not significantly differ between Ph+ AML and CML-MBC. Ph+ AML without CML-like features appeared to have a better outcome compared to Ph+ AML with CML-like features; ACA in Ph+ AML may confer an even worse prognosis.

CONCLUSIONS

Our results indicate that patients with Ph+ AML share similar genetic profiles and clinical outcomes with those with CML-MBC, thus should be classified as a high-risk entity.

Relationship between leukaemic stem cells and hematopoietic stem cells and their clinical application

The world is aging and with it an associated increase in malignancies. Haematological malignancies especially Acute Myeloid Leukemia (AML) are no exception to this trend. With scientific advances, development of new AML treatments has improved patient mortality. One future research interest would be Leukeamic Stem Cells (LSC). This review aims to briefly highlight main LSC characteristics and their relationship with hematopoietic stem cells. Key LSC characteristics include dysregulated apoptosis, capacity for self-renewal, genomic instability, dysregulated energetics, immune privilege and an altered tumor microenvironment. Similar characteristics are also found in HSCs though in a regulated form. Classifying these characteristics will aid in the development of clinical biomarkers for LSC which is a potential clinical application of LSC biology. LSC biomarkers might prove to be critical in future AML management through improving accuracy of AML diagnosis, providing targeted treatment to minimize side effects, refinement of prognosis and relapse risk for earlier intervention.

Diagnosis of rare subtypes of acute myeloid leukaemia and related neoplasms

The diagnosis of acute myeloid leukaemia and related neoplasms in adults is challenging as this requires the integration of clinical findings, morphology, immunophenotype, cytogenetics, and molecular genetic findings. Lack of familiarity with rare subtypes of acute leukaemia hinders the diagnosis. In this review, we will describe diagnostic findings of several rare acute myeloid leukaemias and related neoplasms that primarily occur in adults including information on presentation, morphology, immunophenotype, genetics, differential diagnosis, and prognosis. Leukaemias discussed include blastic plasmacytoid dendritic cell neoplasm, acute myeloid leukaemia with t(6;9) (p23;q34.1); DEK-NUP214, acute myeloid leukaemia with inv(3)(q21.3q26.2) or t(3;3)(q21.3;q26.2); GATA2, MECOM, acute myeloid leukaemia with BCR-ABL1, acute leukaemias of ambiguous lineage, acute myeloid leukaemia with mutated RUNX1, pure erythroid leukaemia, acute panmyelosis with myelofibrosis, and acute basophilic leukaemia. Case studies with morphological features of the nine subtypes of acute myeloid leukaemia and related neoplasms have been included, and additional evidence available since publication of the 2016 World Health Organization Classification has been added to each subtype.

Clinical and genomic characterization of patients diagnosed with the provisional entity acute myeloid leukemia with BCR-ABL1, a Swedish population-based study

Acute myeloid leukemia (AML) with t(9;22)(q34;q11), also known as AML with BCR-ABL1, is a rare, provisional entity in the WHO 2016 classification and is considered a high-risk disease according to the European LeukemiaNet 2017 risk stratification. We here present a retrospective, population-based study of this disease entity from the Swedish Acute Leukemia Registry. By strict clinical inclusion criteria we aimed to identify genetic markers further distinguishing AML with t(9;22) as a separate entity. Twenty-five patients were identified and next-generation sequencing using a 54-gene panel was performed in 21 cases. Interestingly, no mutations were found in NPM1, FLT3, or DNMT3A, three frequently mutated genes in AML. Instead, RUNX1 was the most commonly mutated gene, with aberrations present in 38% of the cases compared to around 10% in de novo AML. Additional mutations were identified in genes involved in RNA splicing (SRSF2, SF3B1) and chromatin regulation (ASXL1, STAG2, BCOR, BCORL1). Less frequently, mutations were found in IDH2, NRAS, TET2, and TP53. The mutational landscape exhibited a similar pattern as recently described in patients with chronic myeloid leukemia (CML) in myeloid blast crisis (BC). Despite the concomitant presence of BCR-ABL1 and RUNX1 mutations in our cohort, both features of high-risk AML, the RUNX1-mutated cases showed a superior overall survival compared to RUNX1 wildtype cases. Our results suggest that the molecular characteristics of AML with t(9;22)/BCR-ABL1 and CML in myeloid BC are similar and do not support a distinction of the two disease entities based on their underlying molecular alterations.

NPM1 Mutated, BCR-ABL1 Positive Myeloid Neoplasms: Review of the Literature

Breakpoint cluster region - Abelson (BCR-ABL1) chimeric protein and mutated Nucleophosmin (NPM1) are often present in hematological cancers, but they rarely coexist in the same disease. Both anomalies are considered founder mutations that inhibit differentiation and apoptosis, but BCR-ABL1 could act as a secondary mutation conferring a proliferative advantage to a pre-neoplastic clone. The 2016 World Health Organization (WHO) classification lists the provisional acute myeloid leukemia (AML) with BCR-ABL1, which must be diagnosed differentially from the rare blast phase (BP) onset of chronic myeloid leukemia (CML), mainly because of the different therapeutic approach in the use of tyrosine kinase inhibitors (TKI). Here we review the BCR/ABL1 plus NPMc+ published cases since 1975 and describe a case from our institution in order to discuss the clinical and molecular features of this rare combination, and report the latest acquisition about an occurrence that could pertain either to the rare AML BCR-ABL1 positive or the even rarer CML-BP with mutated NPM1 at the onset. Differential diagnosis is based on careful analysis of genotypic and phenotypic features and anamnestic, clinical evolution, and background data. Therapeutic decisions must consider the broader clinical aspects, the comparatively mild effects of TKI therapy versus the great benefit that might bring to most of the patients, as may be incidentally demonstrated by our case history.

Acute Myeloid Leukemia with Concomitant BCR-ABL and NPM1 Mutations

We present a case report of a patient with acute myeloid leukemia (AML) characterized by the simultaneous presence of nucleophosmin 1 (NPM1) mutation and the breakpoint cluster region-Abelson (BCR-ABL) fusion oncogene. Our findings emphasize the importance of routinely including BCR-ABL in the diagnostic workup of AML in order to offer to the patients the most appropriate risk category and treatment options.

Philadelphia chromosome positive AML arising from JAK2-positive myelofibrosis

Background

A feature of myeloproliferative neoplasia is transforming to more aggressive and malignant myeloid neoplasia, including acute myeloid leukemia. Different pathogenesis mechanisms participate in transformation, including transformation of existing potential preleukemic clones, since JAK2-mutant myeloproliferative neoplasms often transform to JAK2 wild-type acute myeloid leukemia.

Case presentation

Here, we present an 80 year old man with a JAK2-V617F mutant primary myelofibrosis. After 10 months the disease transform into a Philadelphia chromosome positive acute myeloid leukemia, detecting the cytogenetic aberration; t(9;22)(q34;q22) encoding the rare BCR-ABL1 fusion gene; e6a2. The patient had treatment response to tyrosine kinases, illustrating the potential benefits of such approach in treating these patients subset.

Conclusion

The case illustrates the potential of leukemic transformation to Philadelphia chromosome positive myeloid malignancies from potential existing preleukemic clones, and the awareness of such an evolution among patients with myeloproliferative neoplasms. Tyrosine kinases have potential effect also in patients presenting without chronic myeloid leukemia and with rare BCR-ABL1 fusion transcripts, and should probably be a part of the treatment approach.

Primary Philadelphia chromosome positive acute myeloid leukemia: A case report

RATIONALE

Philadelphia chromosome positive acute myeloid leukemia (Ph+ AML) is a rare subtype of AML that is now included as a provisional entity in the 2016 revised WHO classification of myeloid malignancies. However, a clear distinction between de novo Ph+ AML and chronic myeloid leukemia blast crisis is challenging. It is still a matter of debate whether Ph+ AML patients should be treated with chemotherapy or tyrosine kinase inhibitors as first-line therapy.

PATIENT CONCERNS

We reported here a case of a 46-year-old man who was diagnosed as Ph+ AML. This diagnosis was confirmed by bone marrow pathology and karyotype analysis of 46, XY, t (9; 22). Further examination, molecular genetic analysis showed BCR/ABL1 (p190) without ABL1 kinase domain mutations, and direct evidence demonstrated in AML by flow cytometry.

DIAGNOSIS

The diagnosis of Ph+ AML was made on May 2016 according to morphology, immunology, cytogenetic, and molecular criteria, and multiple organ failure was also diagnosed.

INTERVENTIONS

The patient was treated with dasatinib as the only medication after experiencing multiple organ failure. Then, he received 2 cycles of chemotherapy with IA (idarubicin 8 mg/m, day 1-3; cytarabine 100 mg/m, day 1-7) in August, 2016.

OUTCOMES

The patient finally achieved a complete molecular remission.

LESSONS

This case study suggests that dasatinib can be a safe and effective treatment for Ph+ AML patients with poor physical condition.

The 2016 WHO classification of acute myeloid leukemia: What the practicing clinician needs to know

In 2016 a revision of the World Health Organization (WHO) classification of acute myeloid leukemia (AML) was introduced that included changes to several disease categories. The WHO approach results in disease categories that are defined by a combination of clinical, morphologic, immunophenotypic, and genetic features in an attempt to define clinically relevant, biologic entities. This review summarizes the WHO approach as well as the priority of specific features for disease classification. Changes to specific categories, including AML with myelodysplasia-related changes, AML with mutated NPM1, AML with biallelic mutations of CEBPA and erythroleukemia are summarized. The importance of additional gene mutations as well as germline predisposition in AML is also reviewed.

Secondary Philadelphia chromosome acquired during therapy of acute leukemia and myelodysplastic syndrome

The Philadelphia chromosome resulting from t(9;22)(q34;q11.2) or its variants is a defining event in chronic myeloid leukemia. It is also observed in several types of de novo acute leukemia, commonly in B lymphoblastic leukemia, and rarely in acute myeloid leukemia, acute leukemia of ambiguous lineage, and T lymphoblastic leukemia. Acquisition of the Philadelphia chromosome during therapy of acute leukemia and myelodysplastic syndrome is rare. We reported 19 patients, including 11 men and 8 women with a median age of 53 years at initial diagnosis. The diagnoses at initial presentation were acute myeloid leukemia (n = 11), myelodysplastic syndrome (n = 5), B lymphoblastic leukemia (n = 2), and T lymphoblastic leukemia (n = 1); no cases carried the Philadelphia chromosome. The Philadelphia chromosome was detected subsequently at relapse, or at refractory stage of acute leukemia or myelodysplastic syndrome. Of 14 patients evaluated for the BCR-ABL1 transcript subtype, 12 had the e1a2 transcript. In 11 of 14 patients, the diseases before and after emergence of the Philadelphia chromosome were clonally related by karyotype or shared gene mutations. Of 15 patients with treatment information available, 7 received chemotherapy alone, 5 received chemotherapy plus tyrosine kinase inhibitors, 2 received tyrosine kinase inhibitors only, and 1 patient was not treated. Twelve patients had follow-up after acquisition of the Philadelphia chromosome; all had persistent/refractory acute leukemia. Thirteen of 15 patients died a median of 3 months after the emergence of the Philadelphia chromosome. In summary, secondary Philadelphia chromosome acquired during therapy is rare, and is associated with the e1a2 transcript subtype, terminal disease stage, and poor outcome.

Molecular Malfeasance Mediating Myeloid Malignancies: The Genetics of Acute Myeloid Leukemia

A remarkable number of different, but recurrent, structural cytogenetic abnormalities have been observed in AML, and the 2016 WHO AML classification system incorporates numerous distinct entities associated with translocations or inversions, as well as others associated with single gene mutations into a category entitled "AML with recurrent genetic abnormalities." The AML classification is heavily reliant on cytogenetic and molecular information based on conventional genetic techniques (including karyotype, fluorescence in situ hybridization, reverse transcriptase polymerase chain reaction, single gene sequencing), but large-scale next generation sequencing is now identifying novel mutations. With targeted next generation sequencing panels now clinically available at many centers, detection of mutations, as well as alterations in epigenetic modifiers, is becoming part of the routine diagnostic evaluation of AML and will likely impact future classification schemes.

Impact of an Additional Chromosome on the Clinical Outcomes of Hematopoietic Stem Cell Transplantation in Philadelphia Chromosome-Positive Acute Myeloid Leukemia in Adults

The incidence of Philadelphia chromosome positivity (Ph⁺) in adults with acute myeloid leukemia (AML) is very low. Ph⁺ AML is considered to be high risk for failure to attain remission or for early relapse after standard chemotherapy. Because of the low incidence of the disease, it has been difficult to determine the best treatment, including the effects of tyrosine kinase inhibitors. We retrospectively analyzed 29 patients with Ph⁺ AML (median age, 45 years; range, 18 to 80) managed at our center between 2002 and 2016. Two patients were not treated at all, 3 received repeated low-dose cytarabine, and 24 were treated with 3 + 7 standard induction chemotherapy. All 27 treated patients also received interim imatinib 400 mg orally until the day of the next chemotherapy cycle began or as conditioning for allogeneic hematopoietic cell transplantation (HCT), which was performed in 17 patients. Of the 29 patients with Ph⁺ AML, 7 (24.1%) had additional inv(16), 3 of whom had therapy-related AML. In the 7 with inv(16), the median age was younger (31 versus 44 years, P = .083) and the complete remission (CR) rate was relatively higher (85.7% versus 54.5%, P = .214) than in those without inv(16). Among the 27 treated patients, 20 (74.1%) achieved CR after standard chemotherapy with interim imatinib and 2 (7.4%) achieved CR after low-dose cytarabine with interim imatinib. After a median follow-up of 65.5 months (range, 13.4 to 156.6), the 5-year overall survival (OS) among all 27 treated patients was 43.1%. For the 17 patients who underwent HCT the 5-year OS of 17 patients (10 in subgroup without inv(16) and 7 in subgroup with inv(16)) treated with allogeneic HCT was 69.3%. All 7 with inv(16) were still alive at the end of the study. In contrast, all patients not treated with HCT died within a median of 6.25 months (range, .2 to 18.2). Interim imatinib combined with chemotherapy yielded an acceptable remission rate in adult patients with Ph⁺ AML. Allogeneic HCT as a postremission therapy provided long-term disease control in two-thirds of those who underwent the transplant. We also demonstrated that inv(16) was related to a favorable outcome in Ph⁺ AML, including therapy-related AML.

Relatively favorable outcome after allogeneic stem cell transplantation for BCR-ABL1-positive AML: A survey from the acute leukemia working party of the European Society for blood and marrow transplantation (EBMT)

The aim of the study was to assess the role of allogeneic stem cell transplantation (SCT) in patients diagnosed with BCR-ABL1-positive acute myeloid leukemia (AML). Fifty-seven patients (median age, 48 years, range: 19-67) with BCR-ABL1 positive AML undergoing SCT were identified. The majority of the patients (70%) received a TKI before the transplant. At SCT 48 patients were in CR (45 in CR1), while 9 patients were transplanted in a more advanced stage of the disease. MRD was negative (BCR-ABL1/ABL < 10⁴ ) at time of SCT in 36.1% (14/40). After SCT, 16 (61.5%) out of 26 patients with MRD positive at transplantation reached MRD negativity. After a median follow-up of 6.3 years (0.7-14.2), NRM, RI, LFS, OS, and GRFS at 5 years were 18.1%, 37%, 44.2%, 53.8%, and 32.1%, respectively. The cumulative incidence of acute GvHD grade II-IV was 16.4%, incidence of chronic GvHD 24.9%, and of extensive cGvHD 21.4%, respectively. In patients who received SCT in CR1, 5-yr NRM, RI, LFS, OS, and GRFS were 15.9%, 36.4%, 46.5%, 59.4%, and 34.9%, respectively. Univariate analysis showed that age (<50 vs. ≥50 years) was associated with RI (5-yr: 22.7 vs. 50%), LFS (5-yr: 61.9 vs. 31.8%), and GRFS (5-yr: 52.4 vs. 18.2%), whereas MRD-negative status before SCT was associated with an improved GRFS (38.9 vs. 16.7%). We conclude that the outcome of patients <50 years of age with BCR-ABL1-positive AML receiving allogeneic SCT in CR is relatively favorable, possibly reflecting the beneficial effect of the use of TKI.

Philadelphia chromosome-positive acute myeloid leukemia with masses and osteolytic lesions: finding of 18F-FDG PET/CT

Philadelphia chromosome-positive acute myeloid leukemia is controversial and difficult to distinguish from the blast phase of chronic myeloid leukemia. As a myeloid neoplasm, rare cases of this leukemia manifest multiple soft-tissue tumors or bone lytic lesions. In this paper, we describe a 49-year-old male patient who had an abrupt onset with sharp chest pain, fever, fatigue, emaciation, and splenomegaly. 18F-fluoro-deoxy-glucose positron emission tomography/computed tomography (18F-FDG PET/CT) result showed diffuse and uneven hypermetabolic lesions in the bone marrow with peripheral bone marrow expansion, multiple soft tissue neoplasms with high 18F-FDG uptake, and lytic bone lesions. Bone marrow smear and biopsy detected aberrant blast cells expressing myeloid rather than lymphoid immunophenotype marker. For the existence of Philadelphia chromosome and BCR-ABL1 fusion gene together with complex chromosome abnormalities, a diagnosis of Philadelphia-positive acute myeloid leukemia was made, although the type (de novo or blast crisis) remained unclear.

Philadelphia chromosome with acute myeloid leukemia and concurrent large B cell lymphoma of different origins: A case report

Philadelphia chromosome with de novo acute myeloid leukemia (Ph + AML) arising from t(9;22) is an uncommon occurrence. Ph + AML is known to respond poorly to conventional chemotherapy. To the best of our knowledge, simultaneous diagnosis of de novo Ph + AML and lymphoma in a single patient has not yet been reported. The present study reports the case of a 37-year-old female patient who presented with bone pain, fever and lymphadenopathy, and was diagnosed as Ph + AML with concurrent diffuse large B cell lymphoma. Combined chemotherapy regimen covering AML and lymphoma was administered, achieving short-term response. However, the therapy soon failed and the patient succumbed to the disease. The present study reports the first case of Ph + AML occurring concurrently with diffuse large B cell lymphoma, and discusses certain differences between Ph + AML and chronic myelogenous leukemia in the myeloid blast crisis phase, as well as the appropriate therapeutic modalities for Ph + AML. In addition, the potential association between Ph + AML and diffuse large B cell lymphoma in this patient was investigated.

Mixed phenotype acute leukemia with t(9;22): success with nonacute myeloid leukemia-type intensive induction therapy and stem cell transplantation

Mixed phenotype acute leukemia with t(9;22) is a rare disease with poor prognosis, and information on optimal treatment is limited. We describe a case where our patient experienced positive outcome after nonacute myeloid leukemia‐type intensive induction therapy followed by postremission therapy with stem cell transplant.

The mutational oncoprint of recurrent cytogenetic abnormalities in adult patients with de novo acute myeloid leukemia

Recurrent chromosomal abnormalities and gene mutations detected at the time of diagnosis of acute myeloid leukemia (AML) are associated with particular disease features, treatment response and survival of AML patients, and are used to denote specific disease entities in the World Health Organization classification of myeloid neoplasms and acute leukemia. However, large studies that integrate cytogenetic and comprehensive mutational information are scarce. We created a comprehensive oncoprint of mutations associated with recurrent cytogenetic findings by combining the information on mutational patterns of 80 cancer- and leukemia-associated genes with cytogenetic findings in 1603 adult patients with de novo AML. We show unique differences in the mutational profiles among major cytogenetic subsets, identify novel associations between recurrent cytogenetic abnormalities and both specific gene mutations and gene functional groups, and reveal differences in cytogenetic and mutational features between patients younger than 60 years and those aged 60 years or older. The identified associations between cytogenetic and molecular genetic data may help guide mutation testing in AML, and result in more focused application of targeted therapy in patients with de novo AML.

Recurrent Cytogenetic Abnormalities in Acute Myeloid Leukemia

The spectrum of chromosomal abnormality associated with leukemogenesis of acute myeloid leukemia (AML) is broad and heterogeneous when compared to chronic myeloid leukemia and other myeloid neoplasms. Recurrent chromosomal translocations such as t(8;21), t(15;17), and inv(16) are frequently detected, but hundreds of other uncommon chromosomal aberrations from AML also exist. This chapter discusses 22 chromosomal abnormalities that are common structural, numerical aberrations, and other important but infrequent (less than 1 %) translocations emphasized in the WHO classification. Brief morphologic, cytogenetic, and clinical characteristics are summarized, so as to provide a concise reference to cancer cytogenetic laboratories. Morphology based on FAB classification is used together with the current WHO classification due to frequent mentioning in a vast number of reference literatures. Characteristic chromosomal aberrations of other myeloid neoplasms such as myelodysplastic syndrome and myeloproliferative neoplasm will be discussed in separate chapters-except for certain abnormalities such as t(9;22) in de novo AML. Gene mutations detected in normal karyotype AML by cutting edge next generation sequencing technology are also briefly mentioned.

Current trends in molecular diagnostics of chronic myeloid leukemia

Nearly 1.5 million people worldwide suffer from chronic myeloid leukemia (CML), characterized by the genetic translocation t(9;22)(q34;q11.2), involving the fusion of the Abelson oncogene (ABL1) with the breakpoint cluster region (BCR) gene. Early onset diagnosis coupled to current therapeutics allow for a treatment success rate of 90, which has focused research on the development of novel diagnostics approaches. In this review, we present a critical perspective on current strategies for CML diagnostics, comparing to gold standard methodologies and with an eye on the future trends on nanotheranostics.

Diagnosis and management of AML in adults: 2017 ELN recommendations from an international expert panel

The first edition of the European LeukemiaNet (ELN) recommendations for diagnosis and management of acute myeloid leukemia (AML) in adults, published in 2010, has found broad acceptance by physicians and investigators caring for patients with AML. Recent advances, for example, in the discovery of the genomic landscape of the disease, in the development of assays for genetic testing and for detecting minimal residual disease (MRD), as well as in the development of novel antileukemic agents, prompted an international panel to provide updated evidence- and expert opinion-based recommendations. The recommendations include a revised version of the ELN genetic categories, a proposal for a response category based on MRD status, and criteria for progressive disease.

BCR-ABL-positive acute myeloid leukemia: a new entity? Analysis of clinical and molecular features

BCR-ABL-positive acute myeloid leukemia (AML) is a rare subtype of AML that is now included as a provisional entity in the 2016 revised WHO classification of myeloid malignancies. Since a clear distinction between de novo BCR-ABL+ AML and chronic myeloid leukemia (CML) blast crisis is challenging in many cases, the existence of de novo BCR-ABL+ AML has been a matter of debate for a long time. However, there is increasing evidence suggesting that BCR-ABL+ AML is in fact a distinct subgroup of AML. In this study, we analyzed all published cases since 1975 as well as cases from our institution in order to present common clinical and molecular features of this rare disease. Our analysis shows that BCR-ABL predominantly occurs in AML-NOS, CBF leukemia, and AML with myelodysplasia-related changes. The most common BCR-ABL transcripts (p190 and p210) are nearly equally distributed. Based on the analysis of published data, we provide a clinical algorithm for the initial differential diagnosis of BCR-ABL+ AML. The prognosis of BCR-ABL+ AML seems to depend on the cytogenetic and/or molecular background rather than on BCR-ABL itself. A therapy with tyrosine kinase inhibitors (TKIs) such as imatinib, dasatinib, or nilotinib is reasonable, but-due to a lack of systematic clinical data-their use cannot be routinely recommended in first-line therapy. Beyond first-line treatment of AML, the use of TKI remains an individual decision, both in combination with intensive chemotherapy and/or as a bridge to allogeneic stem cell transplantation. In each single case, potential benefits have to be weighed against potential risks.

The Philadelphia chromosome in leukemogenesis

The truncated chromosome 22 that results from the reciprocal translocation t(9;22)(q34;q11) is known as the Philadelphia chromosome (Ph) and is a hallmark of chronic myeloid leukemia (CML). In leukemia cells, Ph not only impairs the physiological signaling pathways but also disrupts genomic stability. This aberrant fusion gene encodes the breakpoint cluster region-proto-oncogene tyrosine-protein kinase (BCR-ABL1) oncogenic protein with persistently enhanced tyrosine kinase activity. The kinase activity is responsible for maintaining proliferation, inhibiting differentiation, and conferring resistance to cell death. During the progression of CML from the chronic phase to the accelerated phase and then to the blast phase, the expression patterns of different BCR-ABL1 transcripts vary. Each BCR-ABL1 transcript is present in a distinct leukemia phenotype, which predicts both response to therapy and clinical outcome. Besides CML, the Ph is found in acute lymphoblastic leukemia, acute myeloid leukemia, and mixed-phenotype acute leukemia. Here, we provide an overview of the clinical presentation and cellular biology of different phenotypes of Ph-positive leukemia and highlight key findings regarding leukemogenesis.

The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia

The World Health Organization (WHO) classification of tumors of the hematopoietic and lymphoid tissues was last updated in 2008. Since then, there have been numerous advances in the identification of unique biomarkers associated with some myeloid neoplasms and acute leukemias, largely derived from gene expression analysis and next-generation sequencing that can significantly improve the diagnostic criteria as well as the prognostic relevance of entities currently included in the WHO classification and that also suggest new entities that should be added. Therefore, there is a clear need for a revision to the current classification. The revisions to the categories of myeloid neoplasms and acute leukemia will be published in a monograph in 2016 and reflect a consensus of opinion of hematopathologists, hematologists, oncologists, and geneticists. The 2016 edition represents a revision of the prior classification rather than an entirely new classification and attempts to incorporate new clinical, prognostic, morphologic, immunophenotypic, and genetic data that have emerged since the last edition. The major changes in the classification and their rationale are presented here.

[Clinical and laboratory characteristics of 12 Ph/BCR-ABL positive acute myeloid leukemia patients]

目的

探讨有利于Ph染色体和（或）BCR-ABL融合基因阳性急性髓系白血病（Ph/BCRABL⁺ AML）诊断的临床和实验室特征。

方法

收集2006年2月至2013年12月收治的12例Ph/BCR-ABL⁺ AML患者资料，以典型慢性髓性白血病急髓变（CML-MBC）患者为对照组，回顾性分析两者临床及实验室特征，并随访生存情况。

结果

12例患者中位年龄27.5岁，无或轻度脾脏肿大者10例（83.3%），FAB分型以M₂和M₄为主，中位外周血和骨髓嗜碱粒细胞比例、巨核细胞数低于典型CML-MBC患者。免疫表型均为髓系表达，表达CD34者8例（66.7%）。11例患者检测到t(9;22)，伴附加染色体异常5例（45.5%），其中1例为inv(16）。12例患者均检测到BCR-ABL融合基因，e1a2型3例（25.0%），余为b2a2/b3a2型，其中1例伴有CBFβ-MYH11表达。6例受检患者中2例存在AML常见突变，其中CEBPA突变1例，FLT3-TKD突变1例。诱导治疗完全缓解(CR) 7例（58.3%），7例接受化疗联合酪氨酸激酶抑制剂（TKI）者6例CR，3例接受单独化疗者1例CR。总体中位生存期16.5个月，异基因造血干细胞移植（allo-HSCT）组为33.5个月，高于非移植组（5.5个月）。

结论

e1a2型融合基因、与AML常见融合基因共表达、存在AML常见突变有利于Ph/BCR-ABL⁺ AML诊断；此类患者诱导缓解率低，生存期短，化疗联合TKI获得缓解后尽早行allo-HSCT是改善其生存的唯一有效途径。

Acute Myeloid Leukemia and Other Types of Disease Progression in Myeloproliferative Neoplasms

OBJECTIVES

This session of the Society for Hematopathology/European Association for Haematopathology workshop focused on disease progression in myeloproliferative neoplasms (MPNs).

METHODS

The session included typical and unusual presentations of chronic myelogenous leukemia (CML), BCR-ABL1 positive; Philadelphia chromosome-negative (Ph-neg) MPNs; and mastocytosis.

RESULTS

Cases of CML illustrated various manifestations of progression, with emphasis on criteria defining stages of the disease. Issues were discussed related to the patterns of recurrence in patients receiving tyrosine kinase inhibitor therapy, including leukemic transformation occurring in a Ph-neg clone. Ph-neg MPN cases highlighted diagnostic approaches used to establish accelerated and blast phases, including cases with significant myelofibrosis and when an adequate bone marrow aspirate smear is not available. The session also included rare cases of aggressive mastocytosis.

CONCLUSIONS

There was agreement that a definitive diagnosis can be challenging in the absence of documented review of prior diagnostic material and clinical history.

The functional interplay between the t(9;22)-associated fusion proteins BCR/ABL and ABL/BCR in Philadelphia chromosome-positive acute lymphatic leukemia

The hallmark of Philadelphia chromosome positive (Ph⁺) leukemia is the BCR/ABL kinase, which is successfully targeted by selective ATP competitors. However, inhibition of BCR/ABL alone is unable to eradicate Ph⁺ leukemia. The t(9;22) is a reciprocal translocation which encodes not only for the der22 (Philadelphia chromosome) related BCR/ABL, but also for der9 related ABL/BCR fusion proteins, which can be detected in 65% of patients with chronic myeloid leukemia (CML) and 100% of patients with Ph⁺ acute lymphatic leukemia (ALL). ABL/BCRs are oncogenes able to influence the lineage commitment of hematopoietic progenitors. Aim of this study was to further disclose the role of p96^ABL/BCR for the pathogenesis of Ph⁺ ALL. The co-expression of p96^ABL/BCR enhanced the kinase activity and as a consequence, the transformation potential of p185^BCR/ABL. Targeting p96^ABL/BCR by RNAi inhibited growth of Ph⁺ ALL cell lines and Ph⁺ ALL patient-derived long-term cultures (PD-LTCs). Our in vitro and in vivo stem cell studies further revealed a functional hierarchy of p96^ABL/BCR and p185^BCR/ABL in hematopoietic stem cells. Co-expression of p96^ABL/BCR abolished the capacity of p185^BCR/ABL to induce a CML-like disease and led to the induction of ALL. Taken together our here presented data reveal an important role of p96^ABL/BCR for the pathogenesis of Ph⁺ ALL.

The t(9;22) is a reciprocal translocation, which causes chronic myeloid leukemia (CML) and a subset of high risk acute lymphatic leukemia (ALL). The derivative chromosome 22 is the so called Philadelphia chromosome (Ph) which encodes the BCR/ABL kinase. Targeting BCR/ABL by selective ATP competitors, such as imatinib or nilotinib, is a well validated therapeutic concept, but unable to definitively eradicate the disease. Little is known about the role of the fusion protein encoded by the reciprocal derivative chromosome 9, the ABL/BCR. In models of Ph⁺ ALL we show that the functional interplay between ABL/BCR and BCR/ABL not only increases the transformation potential of BCR/ABL but is also indispensable for the growth and survival of Ph⁺ ALL leukemic cells. The presence of ABL/BCR changed the phenotype of the leukemia most likely due to its capacity to influence the stem cell population as shown by our in vivo data. Taken together our here presented data reveal an important role of p96^ABL/BCR for the pathogenesis of Ph⁺ ALL.

Pathway and network approaches for identification of cancer signature markers from omics data

The advancement of high throughput omic technologies during the past few years has made it possible to perform many complex assays in a much shorter time than the traditional approaches. The rapid accumulation and wide availability of omic data generated by these technologies offer great opportunities to unravel disease mechanisms, but also presents significant challenges to extract knowledge from such massive data and to evaluate the findings. To address these challenges, a number of pathway and network based approaches have been introduced. This review article evaluates these methods and discusses their application in cancer biomarker discovery using hepatocellular carcinoma (HCC) as an example.

Disruption of IKAROS activity in primitive chronic-phase CML cells mimics myeloid disease progression

Without effective therapy, chronic-phase chronic myeloid leukemia (CP-CML) evolves into an acute leukemia (blast crisis [BC]) that displays either myeloid or B-lymphoid characteristics. This transition is often preceded by a clinically recognized, but biologically poorly characterized, accelerated phase (AP). Here, we report that IKAROS protein is absent or reduced in bone marrow blasts from most CML patients with advanced myeloid disease (AP or BC). This contrasts with primitive CP-CML cells and BCR-ABL1-negative acute myeloid leukemia blasts, which express readily detectable IKAROS. To investigate whether loss of IKAROS contributes to myeloid disease progression in CP-CML, we examined the effects of forced expression of a dominant-negative isoform of IKAROS (IK6) in CP-CML patients' CD34(+) cells. We confirmed that IK6 disrupts IKAROS activity in transduced CP-CML cells and showed that it confers on them features of AP-CML, including a prolonged increased output in vitro and in xenografted mice of primitive cells with an enhanced ability to differentiate into basophils. Expression of IK6 in CD34(+) CP-CML cells also led to activation of signal transducer and activator of transcription 5 and transcriptional repression of its negative regulators. These findings implicate loss of IKAROS as a frequent step and potential diagnostic harbinger of progressive myeloid disease in CML patients.

A dominant-negative isoform of IKAROS expands primitive normal human hematopoietic cells

Disrupted IKAROS activity is a recurrent feature of some human leukemias, but effects on normal human hematopoietic cells are largely unknown. Here, we used lentivirally mediated expression of a dominant-negative isoform of IKAROS (IK6) to block normal IKAROS activity in primitive human cord blood cells and their progeny. This produced a marked (10-fold) increase in serially transplantable multipotent IK6⁺ cells as well as increased outputs of normally differentiating B cells and granulocytes in transplanted immunodeficient mice, without producing leukemia. Accompanying T/natural killer (NK) cell outputs were unaltered, and erythroid and platelet production was reduced. Mechanistically, IK6 specifically increased human granulopoietic progenitor sensitivity to two growth factors and activated CREB and its targets (c-FOS and Cyclin B1). In more primitive human cells, IK6 prematurely initiated a B cell transcriptional program without affecting the hematopoietic stem cell-associated gene expression profile. Some of these effects were species specific, thus identifying novel roles of IKAROS in regulating normal human hematopoietic cells.

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IKAROS protein is abundantly expressed in primitive human hematopoietic cells

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IK6 enhances human blood stem cell expansion in vivo without causing leukemia

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IK6 has a unique profile of lineage-specific effects on human hematopoietic cells

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IK6 activates B-lineage transcripts prematurely in human blood stem cells