Independent prognostic factors for AML outcome

White blood cell count nadir to zero following intensive chemotherapy as a predictive factor for patients with acute myeloid leukemia

Predictors for response to intensive therapy in AML have focused on baseline factors: percent leukemic blasts in marrow, cytogenetic/molecular genetic abnormalities, and presence of secondary AML. Non-baseline dynamic factors, occurring after induction but before response, may be useful for decisions related to salvage chemotherapy. We hypothesized white blood cell (WBC) count nadir after induction may be a real time indicator of treatment efficacy. We also examined whether time to stem cell transplant (SCT) or baseline molecular genetic abnormalities are associated with a low nadir. Data showed WBC nadir = 0 was a negative predictor for response to intensive induction and was correlated with reduced overall survival and progression free survival. Patients with WBC nadir = 0 did not have a significantly longer time to SCT, and none of the mutations increased the likelihood of reaching WBC nadir = 0. WBC nadir may be a useful real-time monitor in AML patients receiving intensive induction chemotherapy.

Pursuing dynamics of minimal residual leukemic subclones in relapsed and refractory acute myeloid leukemia during conventional therapy

BACKGROUND

Acute myeloid leukemia (AML) is characterized by clonal heterogeneity, leading to frequent relapses and drug resistance despite intensive clinical therapy. Although AML's clonal architecture has been addressed in many studies, practical monitoring of dynamic changes in those subclones during relapse and treatment is still understudied.

METHOD

Fifteen longitudinal bone marrow (BM) samples were collected from three relapsed and refractory (R/R) AML patients. Using droplet digital polymerase chain reaction (ddPCR), the frequencies of patient's leukemic variants were assessed in seven cell populations that were isolated from each BM sample based on cellular phenotypes. By quantifying mutant clones at the diagnosis, remission, and relapse stages, the distribution of AML subclones was sequentially monitored.

RESULTS

Minimal residual (MR) leukemic subclones exhibit heterogeneous distribution among BM cell populations, including mature leukocyte populations. During AML progression, these subclones undergo active phenotypic transitions and repopulate into distinct cell population regardless of normal hematopoiesis hierarchic order. Of these, MR subclones in progenitor populations of patient BM predominantly carry MR leukemic properties, leading to more robust expansion and stubborn persistence than those in mature populations. Moreover, a minor subset of MR leukemic subclones could be sustained at an extremely low frequency without clonal expansion during relapse.

CONCLUSIONS

In this study, we observed treatment persistent MR leukemic subclones and their phenotypic changes during the treatment process of R/R AML patients. This underscores the importance of preemptive inhibition of clonal promiscuity in R/R AML, proposing a practical method for monitoring AML MR subclones.

Clinical outcome and prognosis of patients with acute myeloid leukemia submitted to chemotherapy with 5 years of follow-up

OBJECTIVE

The purpose of this study was to evaluate the clinical-epidemiological profile, associated risk factors and clinical outcomes of patients with acute myeloid leukemia (AML), identifying the main causes of morbidity and mortality and overall survival rate of patients at five years of follow-up.

METHOD

This was a retrospective cohort study evaluating the prognosis and clinical outcomes of 222 patients diagnosed with AML at three large hematology centers in Ceará (northeastern Brazil) over a period of five years.

RESULTS

The mean age at diagnosis was 44.1 ± 16 years, with a female prevalence of 1.3:1. No additional relevant risk factors associated with the development of AML were found, except for the well-established cytogenetic assessment. The overall 5-year survival rate was 39.4% (95%CI: 35.47 - 42.17). The main causes of death were disease progression (37.72%; n = 84) and sepsis (31.58%; n = 70).

CONCLUSION

The clinical outcomes in our sample of AML patients were similar to those of other reported groups. Disease progression and infection were the main causes of death. Access to diagnostic flow cytometry and karyotyping was greater in our sample than in the national average. As expected, overall survival differed significantly according to the risk, as determined by cytogenetic testing.

A new prognostic risk model for acute myeloid leukemia patients based on telomere-related genes

Telomere maintenance is critical to ensure unlimited cancer cell proliferation, but the role of telomere-related genes in acute myeloid leukemia (AML) has not yet been thoroughly discussed. This study aims to develop a new prognostic risk model based on telomere-related genes and analyze potential mechanisms and targets. Cox regression analyses were used to build the prognostic risk model. Kaplan-Meier (KM) survival analysis and receiver operating characteristic (ROC) curve were used to assess the model performance. At the same time, we analyzed the relationship between the risk score and chemotherapy and immunotherapy and preliminarily explored possible mechanisms of immune resistance. The real-time polymerase chain reaction (PCR) was used to detect the prognosis gene expression levels. Finally, a prognostic signature of six telomere-related genes (TGPS6) including ALDH2, CDK18, DNMT3B, FRAT2, LGALSL, and RBL2 was constructed. The TGPS6 score was confirmed as an independent prognostic factor (HR 2.74, CI [2.13-3.53], p < 0.001) in AML and the five-year area under the ROC curve (AUC) value of the score in the training and validation set reached 0.74, 0.81 respectively. In addition, the TGPS6 perfected the European LeukemiaNet (ELN) 2017 prognosis risk stratification and performed well in both AML and cytogenetically normal AML (CN-AML) cohorts. The TGPS6 score also provided a reference for chemotherapy and immunotherapy in patients with AML.

Economic burden of acute myeloid leukemia on patients in a resource-limited tertiary hospital in the Philippines

INTRODUCTION

The remission induction treatment for acute myeloid leukemia (AML) has remained unchanged in the resource-limited setting in the Philippines. AML treatment consists of induction chemotherapy followed by high dose consolidation chemotherapy or allogeneic hematopoietic stem cell transplantation. In the Philippines, the Filipino household bears the burden of health care cost of hospitalization expenditure. Insights into the treatment costs becomes an essential requirement as these guides the allocation of resources to scheme health programs.

METHOD

This study involved a retrospective cohort analysis of AML patients who underwent treatment for AML. Review of the statements of account per admission per patient during treatment for remission induction, consolidation, relapsed and refractory disease and best supportive care from 2017 to 2019. Of the 251 eligible patients, 190 patients were included.

RESULT

The mean healthcare expenditure for remission induction chemotherapy (Phase 1) was US $2, 504.78 (Php 125,239.29). While 3 to 4 cycles of consolidation chemotherapy cost an average of US $3,222.72 (Php 162,103.20). For patients who had relapsed and refractory disease, an additional mean cost of US $3,163.32 (Php 159,115.28) and US $2, 914.72 (Php 146,610.55) were incurred, respectively. The average cost of palliative care was US $1,687.00 (Php 84,856.59).

CONCLUSION

The cost of chemotherapy and other therapeutics bear most of the weight of the direct healthcare cost. The cost of AML treatment represents a significant economic burden for patients and the institution. The cost increases as patients proceed through subsequent lines of treatment for induction failure. Existing subsidy for health insurance benefits could still be improved for appropriate source allocation of resources.

Ribosomal protein control of hematopoietic stem cell transformation through direct, non-canonical regulation of metabolism

We report here that expression of the ribosomal protein, RPL22, is frequently reduced in human myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML); reduced RPL22 expression is associated with worse outcomes. Mice null for Rpl22 display characteristics of an MDS-like syndrome and develop leukemia at an accelerated rate. Rpl22-deficient mice also display enhanced hematopoietic stem cell (HSC) self-renewal and obstructed differentiation potential, which arises not from reduced protein synthesis but from increased expression of the Rpl22 target, ALOX12, an upstream regulator of fatty acid oxidation (FAO). The increased FAO mediated by Rpl22-deficiency also persists in leukemia cells and promotes their survival. Altogether, these findings reveal that Rpl22 insufficiency enhances the leukemia potential of HSC via non-canonical de-repression of its target, ALOX12, which enhances FAO, a process that may serve as a therapeutic vulnerability of Rpl22 low MDS and AML leukemia cells.

Highlights

RPL22 insufficiency is observed in MDS/AML and is associated with reduced survivalRpl22-deficiency produces an MDS-like syndrome and facilitates leukemogenesisRpl22-deficiency does not impair global protein synthesis by HSCRpl22 controls leukemia cell survival by non-canonical regulation of lipid oxidation eTOC: Rpl22 controls the function and transformation potential of hematopoietic stem cells through effects on ALOX12 expression, a regulator of fatty acid oxidation.

Acute Myeloid Leukemia Stem Cells in Minimal/Measurable Residual Disease Detection

Acute myeloid leukemia (AML) is a hematological malignancy characterized by an abundance of incompletely matured or immature clonally derived hematopoietic precursors called leukemic blasts. Rare leukemia stem cells (LSCs) that can self-renew as well as give rise to leukemic progenitors comprising the bulk of leukemic blasts are considered the cellular reservoir of disease initiation and maintenance. LSCs are widely thought to be relatively resistant as well as adaptive to chemotherapy and can cause disease relapse. Therefore, it is imperative to understand the molecular bases of LSC forms and functions during different stages of disease progression, so we can more accurately identify these cells and design therapies to target them. Irrespective of the morphological, cytogenetic, and cellular heterogeneity of AML, the uniform, singularly important and independently significant prognosticator of disease response to therapy and patient outcome is measurable or minimal residual disease (MRD) detection, defined by residual disease detection below the morphology-based 5% blast threshold. The importance of LSC identification and frequency estimation during MRD detection, in order to make MRD more effective in predicting disease relapse and modifying therapeutic regimen is becoming increasingly apparent. This review focuses on summarizing functional and cellular composition-based LSC identification and linking those studies to current techniques of MRD detection to suggest LSC-inclusive MRD detection as well as outline outstanding questions that need to be addressed to improve the future of AML clinical management and treatment outcomes.

Combining the HCT-CI, G8, and AML-Score for Fitness Evaluation of Elderly Patients with Acute Myeloid Leukemia: A Single Center Analysis

BACKGROUND

Accurate assessment of elderly acute myeloid leukemia (AML) patients is essential before intensive induction chemotherapy and subsequent allogeneic hematopoietic stem cell transplantation. In this context, we investigated the capacity of three scores for frailty prediction.

METHODS

At diagnosis, 197 patients were clinically evaluated for appropriate treatment intensity. In parallel and independently, the G8-score, the Hematopoietic Stem Cell Index (HCT-CI) and the AML-score for CR were determined for each patient and analyzed with respect to overall survival (OS).

RESULTS

The G8-score and the HCT-CI were able to significantly separate "fit" from "unfit" patients, <0.001 and p = 0.008. In univariate Cox models, the predictive role for OS was confirmed: for the G8-score (HR: 2.35, 95% CI 1.53-3.60, p < 0.001), the HCT-CI (HR: 1.91, 95% CI 1.17-3.11, p = 0.009) and the AML-score (HR: 5.59, 95% CI 2.04-15.31, p = 0.001), the latter was subsequently used to verify the cohort. In the multivariate Cox model, the results were confirmed for the G8- (HR: 2.03, p < 0.001) and AML-score (HR: 3.27, p = 0.001). Of interest, when combining the scores, their prediction capacity was significantly enhanced, p < 0.001.

CONCLUSIONS

The G8-, the HCTCI and the AML-score represent valid tools in the frailty assessment of elderly AML patients at diagnosis.

The prognostic role of C-KIT, TET1 and TET2 gene expression in Acute Myeloid Leukemia

AIM

was to assess the role of C-KIT, TET1 and TET2 expression in the diagnosis and prognosis of acute myeloblastic leukemia (AML).

METHODS

The expression levels of C-KIT, TET1 and TET2 were assessed in the bone marrow (BM) aspirate of 152 AML patients compared to 20 healthy control using quantitative real-time polymerase chain reaction (qRT-PCR). Data were correlated with the clinico-pathological features of the patients, response to treatment, disease-free survival (DFS), and overall survival (OS) rates.

RESULTS

C-KIT, TET1 and TET2 were significantly upregulated in AML patients [0.25 (0-11.6), 0.0113 (0-3.301), and 0.07 (0-4); respectively], compared to the control group [0.013 (0.005-0.250), P < 0.001, 0.001 (0-0.006), P < 0.001, and 0.02 (0.008-0.055), P = 0.019; respectively]. The sensitivity, specificity, and area under curve of of C-KIT were (48.7%, 100%, 0.855; respectively, P = 0.001), and that of TET1 were (63.4%, 100%, 0.897; respectively, P = 0.001), while that of TET2 were (56.8%, 100%, 0.766; respectively, P = 0.019). When combining the three markers, the sensitivity was 77.5%, however it reached the highest sensitivity (78.6%) and specificity (100%) when combining both c-KIT + TET1 together for the diagnosis of AML. C-KIT overexpression associated with shorter DFS (P = 0.05) and increased incidence of relapse (P = 0.019). Lymph nodes involvement [HR = 2.200, P = 0.005] is an independent risk factor for shorter OS rate of AML patients. Increased BM blast % [HR = 7.768, P = 0.002], and FLT3-ITD mutation [HR = 2.989, P = 0.032] are independent risk factors for shorter DSF rate of the patients.

CONCLUSION

C-KIT, TET1, and TET2 could be used as possible useful biomarkers for the diagnosis of AML.

MYC overexpression is associated with an early disease progression from MDS to AML

Recent studies demonstrated that MYC epigenetically regulates AML cell survival and differentiation by suppressing IDH1/2-TET2-5hmC signaling and that MYC overexpression is associated with poor survival outcomes in multiple AML patient cohorts. However, the oncogenic roles of MYC in MDS remain to be explored. A total of 41 patients with de novo MDS were retrospectively identified using the Total Cancer Care database at the Moffitt Cancer Center. A total of 61 % of patients had low MYC expression and 39 % of patients had high MYC expression defined as MYC reactivity by immunohistochemical staining in ≥5% of bone marrow (BM) cells at the time of MDS diagnosis. The median MDS-to-AML progression free survival (PFS) was significantly shorter in the high MYC group (median PFS 9.3 vs. 17.7 months, HR = 2.328, p = 0.013). Further, overall survival (OS) was also shorter in the high MYC patients (median OS 19.7 vs. 51.7 months, HR = 2.299, p = 0.053). Multivariate analyses demonstrated that high MYC expression is an independent poor prognostic factor for the MDS-to-AML progression (HR = 2.275, p = 0.046). Our observations indicate that MYC may play a crucial role in MDS transformation to AML and the underlying mechanisms of MYC-driven MDS clonal expansion and leukemic transformation require further investigation.

Types, Clinical Features, and Survival Outcomes of Patients with Acute Myeloid Leukemia in Thailand: A 3-Year Prospective Multicenter Study from the Thai Acute Leukemia Study Group (TALSG)

BACKGROUND

Acute myeloid leukemia (AML) is a common, challenging hematologic malignancy worldwide. Thai data on its characteristics and outcomes have never been systematically reported, to our knowledge. The objective of this study was to determine the clinical features and outcomes of Thai patients with AML.

PATIENTS AND METHODS

This was a prospective observational study of nine academic hospitals. Patients with newly diagnosed AML were invited to register online.

RESULTS

A total of 679 patients with AML were included. The presence of circulating peripheral blood blasts was correlated with a high white blood cell count. Acute promyelocytic leukemia (APL) had predominantly lower white blood cell counts and higher proportions without peripheral blood blasts compared with non-APL AML. Disseminated intravascular coagulation was commonly presented in APL (37.7%). Splenomegaly and normal platelet count were more frequently seen in patients with Philadelphia chromosome-positive AML. The median follow-up time for those who survived more than 1 year was 28.0 months. One-year overall survival rates for non-APL AML and APL were 31.9% and 88.2%, respectively; 2-year overall survival rates were 29.6% and 88.2%, respectively. Hematopoietic stem cell transplantation could improve survival in non-APL AML.

CONCLUSION

APL should be considered despite absence of peripheral blood blast. This study demonstrates poor outcome of Thai AML and more research to improve outcomes are underway. Expanding access to hematopoietic stem cell transplantation should be considered in Thailand.

Clinical benefit of glasdegib plus low-dose cytarabine in patients with de novo and secondary acute myeloid leukemia: long-term analysis of a phase II randomized trial

This analysis from the phase II BRIGHT AML 1003 trial reports the long-term efficacy and safety of glasdegib + low-dose cytarabine (LDAC) in patients with acute myeloid leukemia ineligible for intensive chemotherapy. The multicenter, open-label study randomized (2:1) patients to receive glasdegib + LDAC (de novo, n = 38; secondary acute myeloid leukemia, n = 40) or LDAC alone (de novo, n = 18; secondary acute myeloid leukemia, n = 20). At the time of analysis, 90% of patients had died, with the longest follow-up since randomization 36 months. The combination of glasdegib and LDAC conferred superior overall survival (OS) versus LDAC alone; hazard ratio (HR) 0.495; (95% confidence interval [CI] 0.325–0.752); p = 0.0004; median OS was 8.3 versus 4.3 months. Improvement in OS was consistent across cytogenetic risk groups. In a post-hoc subgroup analysis, a survival trend with glasdegib + LDAC was observed in patients with de novo acute myeloid leukemia (HR 0.720; 95% CI 0.395–1.312; p = 0.14; median OS 6.6 vs 4.3 months) and secondary acute myeloid leukemia (HR 0.287; 95% CI 0.151–0.548; p < 0.0001; median OS 9.1 vs 4.1 months). The incidence of adverse events in the glasdegib + LDAC arm decreased after 90 days’ therapy: 83.7% versus 98.7% during the first 90 days. Glasdegib + LDAC versus LDAC alone continued to demonstrate superior OS in patients with acute myeloid leukemia; the clinical benefit with glasdegib + LDAC was particularly prominent in patients with secondary acute myeloid leukemia. ClinicalTrials.gov identifier: NCT01546038.

C-Type Lectin-Like Molecule-1 as a Biomarker for Diagnosis and Prognosis in Acute Myeloid Leukemia: A Preliminary Study

Objective

AML is a heterogeneous disease both in genomic and proteomic backgrounds, and variable outcomes may appear in the same cytogenetic risk group. Therefore, it is still necessary to identify new antigens that contribute to diagnostic information and to refine the current risk stratification.

Methods

The expression of C-type lectin-like molecule-1 (CLL-1) in AML blasts was examined in 52 patients with newly diagnosed or relapsed/refractory AML and was compared with two other classic markers CD33 and CD34 in AML, in order to assess the value of CLL-1 as an independent biomarker or in combination with other markers for diagnosis in AML. Subsequently, the value of CLL-1 as a biomarker for prognosis was assessed in this malignant tumor.

Results

The results showed that CLL-1 was expressed on the cell surface of the majority of AML blasts (78.8%) and also expressed on leukemic stem cells in varying degree but absent on normal hematopoietic stem cells. Notably, CLL-1 was able to complement the classic markers CD33 or CD34. After dividing the cases into CLL-1^high and CLL-1^low groups according to cutoff 59.0%, we discovered that event-free survival and overall survival (OS) of the CLL-1^low group were significantly lower than that of the CLL-1^high group, and low CLL-1 expression seems to be independently associated with shorter OS.

Conclusions

These preliminary observations identified CLL-1 as a biomarker for diagnosis and prognosis of AML.

Molecular Insights into the Potential of Extracellular Vesicles Released from Mesenchymal Stem Cells and Other Cells in the Therapy of Hematologic Malignancies

Hematologic cancer encompasses the heterogeneous group of neoplasms that affect different stages of blood cell linages. Despite the significant improvements made in the new modalities of anticancer therapy, many forms of blood cancer remain untreatable, putting the afflicted patients at high risk of death. Therefore, there has been an urgent need for novel therapy to improve the clinical outcomes of patients with blood cancer. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) have been reported to possess an anticancer activity. This review discusses (i) the therapeutic potential of MSC-EVs against blood cancer, (ii) the possibility of using EVs from sources other than MSCs as a mean for blood cancer vaccination and drug delivery, and (iii) areas to be optimized for MSC-EV-based clinical application on blood malignancies.

Immunosuppressive role of CD11b+ CD33+ HLA-DR- myeloid-derived suppressor cells-like blast subpopulation in acute myeloid leukemia

OBJECTIVE

Myeloid-derived suppressor cells (MDSCs) facilitate tumor growth and development by suppressing T cell function; however, their role in acute myeloid leukemia (AML) remains unclear. Here, we investigated the immunosuppressive role and prognostic value of blasts with an MDSC-like phenotype.

METHODS

CD11b⁺ CD33⁺ HLA-DR^- MDSC-like blasts from bone marrow mononuclear cells of patients with AML were analyzed. To investigate their T cell-suppressing function, MDSC-like blasts were isolated using flow cytometry and co-cultured with CD8⁺ cytotoxic T cells and NB4 leukemic cells. Treatment outcomes were then compared between the MDSC-like blasts low (≤9.76%) and high (>9.76%) groups to identify clinical significance.

RESULTS

MDSC-like blasts showed higher expression of arginase-1 and inducible nitric oxide synthase. Isolated MDSC-like blasts significantly suppressed CD8⁺ T cell proliferation induced by phytohemagglutinin A. NB4 cell proliferation was significantly suppressed upon co-culture with CD8⁺ cytotoxic T cells and partially restored upon co-culture with MDSC-like blasts. Patients with high MDSC-like blasts at diagnosis showed substantially shorter overall survival and leukemia-free survival relative to low MDSC-like blasts patients, with subgroup analysis showing statistically significant differences in patients not receiving allogeneic hematopoietic stem cell transplantation.

CONCLUSION

We demonstrated that MDSC-like blasts drive AML-specific immune-escape mechanisms by suppressing T cell proliferation and restoring T cell-suppressed NB4 cell proliferation, with clinically higher fractions of MDSC-like blasts at diagnosis resulting in poor prognosis.

Molecular Landscape of Acute Myeloid Leukemia: Prognostic and Therapeutic Implications

PURPOSE OF REVIEW

The field of acute myeloid leukemia (AML) has been revolutionized in recent years by the advent of high-throughput techniques, such as next-generation sequencing. In this review, we will discuss some of the recently identified mutations that have defined a new molecular landscape in this disease, as well as their prognostic, predictive, and therapeutic implications.

RECENT FINDINGS

Recent studies have shown how many cases of AML evolve from a premalignant period of latency characterized by the accumulation of several mutations and the emergence of one or multiple dominant clones. The pattern of co-occurring mutations and cytogenetic abnormalities at diagnosis defines risk and can determine therapeutic approaches to induce remission. Besides the genetic landscape at diagnosis, the continued presence of particular gene mutations during or after treatment carries prognostic information that should further influence strategies to maintain remission in the long term. The recent progress made in AML research is a seminal example of how basic science can translate into improving clinical practice. Our ability to characterize the genomic landscape of individual patients has not only improved our ability to diagnose and prognosticate but is also bringing the promise of precision medicine to fruition in the field.

AML in Saudi Arabia: Analysis According to the European LeukaemiaNet 2017 Cytogenetic Classification

INTRODUCTION

To the best of our knowledge, few studies have addressed the prognosis of patients with acute myeloid leukemia (AML) in Saudi Arabia. The present study retrospectively analyzed the prognostic factors in patients with de novo AML at a single institution owing to the observation of some differences with the reported data from the Western world.

PATIENTS AND METHODS

Patients with de novo AML who had been referred to King Abdulla Medical City were included. All patients had undergone bone marrow aspiration, biopsy, flow cytometry, cytogenetics (conventional and fluorescence in situ hybridization panel performed at Mayo Clinic), molecular tests, and other routine tests.

RESULTS

The data from 170 patients were reviewed. Of the 170 patients, 26 had had acute promyelocytic leukemia, 16 with AML had received less intensive therapy, 119 had received intensive induction, and 8 had refused treatment. The present analysis was limited to the 119 patients who had received intensive induction therapy. For the major cytogenetic categories, 17 of 27 patients with core binding factor leukemia (62.9%) were reassigned to the intermediate (n = 10; 37%) or unfavorable (n = 7; 25.9%) risk group according to the FLT3-ITD and NPM results. Of the 50 cases of normal cytogenetic findings, 2 (4%) were considered unfavorable, 12 (24%), favorable, 30 intermediate (60%), and 6 (12%) unknown. The median leukemia-free survival was 21.5 months. The median overall survival was 16.4 ± 2.2 months, with a 3-year survival rate of 37.2%. Multivariate Cox regression analysis revealed that the cytogenetics results (P = .002) and the presence of FLT-3 (P = .03) were independent prognostic factors for relapse-free survival. Performance status, response, relapse, and cytogenetics findings were independent prognostic factors for survival.

CONCLUSIONS

The results from the present study revealed some differences in patient age and cytogenetic risk groups for patients with AML in our region and those in the Western world, including a younger median age, relevance of core binding factor leukemia, and a greater incidence of monosomies.

Multi-study reanalysis of 2,213 acute myeloid leukemia patients reveals age- and sex-dependent gene expression signatures

In 2019 it is estimated that more than 21,000 new acute myeloid leukemia (AML) patients will be diagnosed in the United States, and nearly 11,000 are expected to die from the disease. AML is primarily diagnosed among the elderly (median 68 years old at diagnosis). Prognoses have significantly improved for younger patients, but as much as 70% of patients over 60 years old will die within a year of diagnosis. In this study, we conducted a reanalysis of 2,213 acute myeloid leukemia patients compared to 548 healthy individuals, using curated publicly available microarray gene expression data. We carried out an analysis of normalized batch corrected data, using a linear model that included considerations for disease, age, sex, and tissue. We identified 974 differentially expressed probe sets and 4 significant pathways associated with AML. Additionally, we identified 375 age- and 70 sex-related probe set expression signatures relevant to AML. Finally, we trained a k nearest neighbors model to classify AML and healthy subjects with 90.9% accuracy. Our findings provide a new reanalysis of public datasets, that enabled the identification of new gene sets relevant to AML that can potentially be used in future experiments and possible stratified disease diagnostics.

MRD in AML: The Role of New Techniques

In the context of precision medicine, assessment of minimal residual disease (MRD) has been used in acute myeloid leukemia (AML) to direct individual treatment programs, including allogeneic stem cell transplantation in patients at high-risk of relapse. One of the limits of this approach has been in the past the paucity of AML markers suitable for MRD assessment. Recently, the number of biomarkers has increased, due to the identification of highly specific leukemia-associated immunophenotypes by multicolor flow-cytometry, and of rare mutated gene sequences by digital droplet PCR, or next-generation sequencing (NGS). In addition, NGS allowed unraveling of clonal heterogeneity, present in AML at initial diagnosis or developing during treatment, which influences reliability of specific biomarkers, that may be unstable during the disease course. The technological advances have increased the application of MRD-based strategies to a significantly higher number of AML patients, and the information deriving from MRD assessment has been used to design individual post-remission protocols and pre-emptive treatments in patients with sub-clinical relapse. This led to the definition of MRD-negative complete remission as outcome definition in the recently published European Leukemianet MRD guidelines. In this review, we summarized the principles of modern technologies and their clinical applications for MRD detection in AML patients, according to the specific leukemic markers.

Prognostic significance of MYC oncoprotein expression on survival outcome in patients with acute myeloid leukemia with myelodysplasia related changes (AML-MRC)

MYC is an oncoprotein that coordinates the expression of genes involved in metabolism, cell differentiation and survival in various types of malignancies. However, the underlying oncogenic mechanisms and the clinical significance of MYC expression in the acute myeloid leukemia with myelodysplasia related changes (AML-MRC) remain to be answered. A total of 135 patients were retrospectively identified using Total Cancer Care (TCC) Moffitt Cancer Center (MCC) databases. Diagnosis of AML-MRC was based on the 2016 WHO classification utilizing bone marrow (BM) evaluation. MYC protein expression level was assessed by immunohistochemistry (IHC) staining using paraffin-embedded BM trephine biopsy samples obtained at the time of diagnosis or relapse. Concurrent somatic mutations were assessed using targeted next generation sequencing that include 54 genes. A total of 38% (n = 51) and 62% (n = 84) patients had high and low MYC expression, respectively. The most common somatic mutation in our cohort was TP53 followed by DNMT3A, and ASXL1. The median OS was significantly longer in low MYC patients (median OS 42.3 vs. 17.05 months, p = 0.0109). Multivariate analysis including MYC expression level, transplantation status, gender and age demonstrated high MYC expression (HR 1.77, 95% CI 1.004-3.104, p = 0.045) to be an independent poor prognostic factor. Further studies are needed to identify the underlying mechanism of MYC driven oncogenesis in AML-MRC. Additionally, the prognostic impact of MYC on the AML survival in a larger cohort that include diverse somatic mutations and chromosomal abnormalities requires further investigation.

A rare case of acute myeloid leukemia with der(1)t(1;19)(p13;p13.1)

We present a case of acute myeloid leukemia with der(1)t(1;19)(p13;p13.1) translocation and RUNX1 mutation. A literature review summarizing the clinical, pathological, and molecular features of the published cases is also presented.

The prognostic impact of tet oncogene family member 2 mutations in patients with acute myeloid leukemia: a systematic-review and meta-analysis

Background

The impact of Tet oncogene family member 2 (TET2) mutations on the prognosis of acute myeloid leukemia (AML) is still controversial. A meta analysis is needed in order to assess the prognostic significance of TET2 mutation in AML.

Methods

Five databases including PubMed, Cochrane, EMBase, China National Knowledge Internet (CNKI) and Wanfang database were retrieved to search studies that investigated the correlation between TET2 mutations and outcomes of AML patients. Pooled hazard ratios (HRs) and odds ratios (ORs) were used to assess the effects of TET2 mutations.

Results

Sixteen studies were included. TET2 mutation was an unfavorable prognostic factor for overall survival (OS: HR = 1.386; P < 0.001) and event-free survival (EFS: HR = 1.594; P = 0.002) in patients with AML. For patients under 65 years of age, TET2 mutation predicted an inferior OS (HR = 1.310, P = 0.051) and EFS (HR = 1.429, P = 0.027). For patients with intermediate-risk cytogenetics (IR-AML), mutant TET2 had a significant association with adverse OS (HR = 0.474; P < 0.001). For patients with normal cytogenetics (CN-AML), mutant TET2 also conferred adverse OS (HR = 1.425; P < 0.001) and EFS (HR = 1.450, P < 0.001). Further, among patients with CN-AML, mutant TET2 was associated with inferior OS (HR = 2.034, P < 0.001) and EFS (HR = 2.140, P < 0.001) in the ELN favorable-risk subgroup and an inferior EFS (HR = 1.487; P < 0.001) in the ELN intermediate-Isubgroup. With respect to treatment outcome, TET2 mutation predicted a significantly lower rate of complete remission (CR) in cases with ELN favorable-risk cytogenetics (OR = 0.460, P = 0.011).

Conclusions

TET2 mutation had adverse impacts on survival and treatment response in AML patients and will contribute to risk-stratification, prognosis prediction and therapy guidance.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5602-8) contains supplementary material, which is available to authorized users.

Prognostic Significance of Complex Karyotypes in Acute Myeloid Leukemia

OPINION STATEMENT

Acute myeloid leukemia (AML) patients with a complex karyotype (CK-AML) show at least 3 unrelated clonal cytogenetic abnormalities with notoriously poor outcome. Such cases fall into either AML with myelodysplasia-related changes or therapy-related AML in the current World Health Organization classification of AML. Allogeneic stem cell transplantation is one of the only treatment modalities that can provide a long-term survival benefit and is recommended as a consolidative treatment in patients who are able to achieve complete remission. Unfortunately, transplantation is also associated with a higher relapse rate and more than half of CK-AML patients relapse from disease within the first 2 years. The probability of achieving remission with traditional induction using cytarabine and daunorubicin or idarubicin ("7 + 3") is so small that investigational therapies should be considered up front in these patients. Less intensive therapeutic backbones, typically using one of the hypomethylating agents, azacitidine or decitabine, minimize toxicity and show a trend toward the improved overall survival. CPX 351 (Vyxeos) is a liposomal formulation of cytarabine and daunorubicin and this encapsulation leads to prolonged exposure to the two drugs. This drug is approved for AML patients with MDS-related changes and therapy-related AML, both of which are frequently associated with complex karyotype. Such patients show improved outcome in trials using this combination. Combination therapy that includes venetoclax (BCL2 inhibitor) with hypomethylating agents may also be appropriate for such patients.

Plasma fibrinogen levels correlate with prognosis and treatment outcome in patients with non-M3 acute myeloid leukemia

To assess plasma fibrinogen levels as a biomarker to predict the prognosis and treatment outcome in acute myeloid leukemia (AML), a retrospective study of 215 patients with AML excluding M3 was conducted in a single center. Patients were divided into low and high group according to the cutoff value of 3.775 g/L obtained by analyzing the receiver operating characteristic (ROC) curve of fibrinogen at diagnosis. Importantly, overall survival (OS) was markedly better in low fibrinogen group (p=.006) as well as disease-free survival (DFS) (p= .045). Furthermore, when patients achieved complete remission (CR), the median plasma fibrinogen levels were dramatically decreased in high fibrinogen group but increased in low fibrinogen group. In conclusion, our data suggest that initial plasma FBG levels can be used as an independent prognostic biomarker affecting OS and DFS, as well as a potential parameter reflecting the treatment outcome in patients with non-M3 AML.

Serum albumin or body mass index: Which prognostic factor for survival in patients with acute myeloblastic leukaemia?

Obesity has been associated with an increased risk of developing acute myeloblastic leukaemia (AML). The outcome of AML patients could thus be dependent on their nutritional status that can be evaluated by the simple measurement of serum albumin (SA) and body mass index (BMI). These two parameters could have a value as prognostic factors to guide patients' management. We evaluated the association between SA levels, BMI, and survival, evaluated as overall survival (OS) and event-free survival. Furthermore, we investigated the association between BMI, SA, and other prognostic factors of interest in AML. This retrospective single-center study included 159 patients diagnosed with AML at Nancy Hospital between 2005 and 2013, treated with aracytine and anthracycline. Forty-four percent of patients presented with normal weight while 56% were obese/overweight. Serum albumin levels were <30 g/L for 49 patients, and ≥30 g/L for 110. Thirty-four patients with low SA levels were also obese. Favourable OS was associated with SA levels ≥30 g/L (HR = 0.467; 95% CI 0.230-0.946; P = .034) but was not impacted by the BMI. Serum albumin levels appear to be an independent prognostic factor in AML and a better parameter than BMI for evaluating the nutritional status of patients at diagnosis.

Distribution of Chromosomal Abnormalities Commonly Observed in Adult Acute Myeloid Leukemia in Pakistan as Predictors of Prognosis

Objectives

The heterogenous response to treatment in acute myeloid leukemia (AML) can be attributed largely to the difference in cytogenetic features identified in between cases. Cytogenetic analysis in acute leukemia is now routinely used to assist patient management, particularly in terms of diagnosis, disease monitoring, prognosis and risk stratification. Knowing about cytogenetic profile at the time of diagnosis is important in order to take critical decisions in management of these patients. The study was conducted to determine the distribution of cytogenetic abnormalities in Pakistani adult patients with AML in order to have insights regarding behavior of the disease.

Methods

A retrospective analysis of all the cases of AML (≥15years old) diagnosed at Aga Khan University from January 2011 to December 2016 was performed. Cytogenetic analysis was made for all cases using the trypsin-Giemsa banding technique. Karyotypes were interpreted using the International System for Human Cytogenetic Nomenclature (ISCN) criteria.

Results

A total of 321 patients were diagnosed with AML during the study period, of which 288 samples successfully yielded metaphase chromosomes. The male to female ratio was 1.7:1. A normal karyotype was present in 61% (n=176) of the cases whereas, 39% (n=112) had an abnormal karyotype. Of the abnormal cases, t (8;21) (q22;q22) and t (15;17) (q22;q12) were identified in 8.3% and 4.9% cases respectively. Adverse prognostic cytogenetic subgroups including complex karyotype, monosomy 7 and t(6;9)(p23;q34) were identified in 9%, 1% and 0.7% patients respectively.

Conclusions

This largest cytogenetic data in adult AML from Pakistan showed comparable prevalence of favorable prognostic karyotype to international data. The prevalence of specific adverse prognostic karyotype was low.

Predictive and Prognostic Markers in Adults With Acute Myeloid Leukemia: A Single-Institution Experience

BACKGROUND

Acute myeloid leukemia (AML) is a heterogeneous malignancy with diverse genetic abnormalities, clinical presentations, and outcomes. Known predictive and prognostic factors in AML include age, performance status, comorbidities, cytogenetics, and molecular mutations. Identifying prognostic and predictive factors can inform the choice of induction therapy and outcomes prediction.

PATIENTS AND METHODS

A retrospective review was performed of 137 adult AML patients from 2010 to 2015. Predictors of complete remission (CR) and overall survival (OS) were determined for patients treated with 3+7 (3 days of anthracycline and 7 days of cytarabine) or hypomethylating agent. Variables associated with CR or OS were assessed using univariate Cox regression and a multivariate Cox model.

RESULTS

The average age was 65 years and 91 patients (66%), sample size is 137 patients had primary AML. Patients in the 3+7 induction group were younger, had a higher bone marrow blast percentage, and more de novo AML compared with those in the hypomethylating agent group (P < .001, P < .001, P = .005, respectively). Univariate logistic regression for CR showed a significant association between age (P < .001), choice of induction (P < .001), and monosomy (P = .015), although only induction with 3+7 (P < .001) and absence of monosomy (P = .042) remained significant in multivariate analysis. Univariate Cox regression indicated that age (P = .003), AML status (de novo or secondary; P = .0277), choice of induction (P = .030), and monosomy (P = .010) had a significant association with OS. Only younger age (P = .018) and absence of monosomy (P = .022) were predictive of OS in multivariate Cox analysis.

CONCLUSION

Positive predictors of CR in adult AML include absence of monosomy and induction treatment with 3+7; whereas positive predictors of OS are younger age and absence of monosomy.

Gene expression profiling of acute myeloid leukemia samples from adult patients with AML-M1 and -M2 through boutique microarrays, real-time PCR and droplet digital PCR

Acute myeloid leukemia (AML) is the most common and severe form of acute leukemia diagnosed in adults. Owing to its heterogeneity, AML is divided into classes associated with different treatment outcomes and specific gene expression profiles. Based on previous studies on AML, in this study, we designed and generated an AML-array containing 900 oligonucleotide probes complementary to human genes implicated in hematopoietic cell differentiation and maturation, proliferation, apoptosis and leukemic transformation. The AML-array was used to hybridize 118 samples from 33 patients with AML of the M1 and M2 subtypes of the French-American-British (FAB) classification and 15 healthy volunteers (HV). Rigorous analysis of the microarray data revealed that 83 genes were differentially expressed between the patients with AML and the HV, including genes not yet discussed in the context of AML pathogenesis. The most overexpressed genes in AML were STMN1, KITLG, CDK6, MCM5, KRAS, CEBPA, MYC, ANGPT1, SRGN, RPLP0, ENO1 and SET, whereas the most underexpressed genes were IFITM1, LTB, FCN1, BIRC3, LYZ, ADD3, S100A9, FCER1G, PTRPE, CD74 and TMSB4X. The overexpression of the CPA3 gene was specific for AML with mutated NPM1 and FLT3. Although the microarray-based method was insufficient to differentiate between any other AML subgroups, quantitative PCR approaches enabled us to identify 3 genes (ANXA3, S100A9 and WT1) whose expression can be used to discriminate between the 2 studied AML FAB subtypes. The expression levels of the ANXA3 and S100A9 genes were increased, whereas those of WT1 were decreased in the AML-M2 compared to the AML-M1 group. We also examined the association between the STMN1, CAT and ABL1 genes, and the FLT3 and NPM1 mutation status. FLT3⁺/NPM1⁻ AML was associated with the highest expression of STMN1, and ABL1 was upregulated in FLT3⁺ AML and CAT in FLT3⁻ AML, irrespectively of the NPM1 mutation status. Moreover, our results indicated that CAT and WT1 gene expression levels correlated with the response to therapy. CAT expression was highest in patients who remained longer under complete remission, whereas WT1 expression increased with treatment resistance. On the whole, this study demonstrates that the AML-array can potentially serve as a first-line screening tool, and may be helpful for the diagnosis of AML, whereas the differentiation between AML subgroups can be more successfully performed with PCR-based analysis of a few marker genes.

Increased activity of both CDK1 and CDK2 is necessary for the combinatorial activity of WEE1 inhibition and cytarabine

Inhibition of WEE1 is emerging as a promising chemosensitization strategy in many cancers including acute leukemia. Our lab and others have demonstrated that a small-molecule inhibitor of WEE1, AZD1775, sensitizes acute leukemia cells to cytarabine; however, a mechanism of combinatorial activity has remained elusive. Thus, we sought to determine the relative contribution of WEE1 targets CDK1 and CDK2 to the combinatorial activity of AZD1775 and cytarabine. To accomplish this, we expressed "WEE1 resistant" CDK1 (CDK1-AF) and CDK2 (CDK2-AF) constructs in a T-ALL cell line. Expression of CDK1/2-AF together, but neither alone, enhanced the anti-proliferative effects, DNA damage and apoptosis induced by cytarabine. Furthermore, pharmacologic inhibition of CDK1 alone or CDK1 and CDK2 together reduced the combinatorial activity of AZD1775 and cytarabine. Thus, increased activity of both CDK1 and CDK2 in response to WEE1 inhibition is necessary for the combinatorial activity of AZD1775 and cytarabine. This suggests the role of WEE1 in cells with accumulated DNA damage extends beyond regulation of CDK1 and the G2/M checkpoint and highlights the importance of WEE1 in mediating progression through the cell cycle.

Minimal Residual Disease in Acute Myeloid Leukemia: Still a Work in Progress?

Minimal residual disease evaluation refers to a series of molecular and immunophenotypical techniques aimed at detecting submicroscopic disease after therapy. As such, its application in acute myeloid leukemia has greatly increased our ability to quantify treatment response, and to determine the chemosensitivity of the disease, as the final product of the drug schedule, dose intensity, biodistribution, and the pharmakogenetic profile of the patient. There is now consistent evidence for the prognostic power of minimal residual disease evaluation in acute myeloid leukemia, which is complementary to the baseline prognostic assessment of the disease. The focus for its use is therefore shifting to individualize treatment based on a deeper evaluation of chemosensitivity and residual tumor burden. In this review, we will summarize the results of the major clinical studies evaluating minimal residual disease in acute myeloid leukemia in adults in recent years and address the technical and practical issues still hampering the spread of these techniques outside controlled clinical trials. We will also briefly speculate on future developments and offer our point of view, and a word of caution, on the present use of minimal residual disease measurements in “real-life” practice. Still, as final standardization and diffusion of the methods are sorted out, we believe that minimal residual disease will soon become the new standard for evaluating response in the treatment of acute myeloid leukemia.

Role of reduced-intensity conditioning allogeneic hematopoietic cell transplantation in older patients with de novo acute myeloid leukemia

Reduced-intensity conditioning (RIC) regimens extend the therapeutic use of allogeneic hematopoietic cell transplantation (HCT) to older patients. The survival trend in 2325 patients aged >50 years presenting with de novo acute myeloid leukemia (AML) who underwent first reduced-intensity HCT (RIC-HCT) was assessed by retrospectively analyzing outcomes between 2000 and 2013. The annual number of RIC-HCTs in Japan was higher in the 2008-2013 period (n = 205/year [1229/6 years]) than in the 2000-2007 period (n = 137/year [1096/8 years]). Overall and disease-free survival were higher in the 2008-2013 period (P < 0.001) because of the improvement in transplant-related mortality (TRM). Survival regarding RIC-HCT for AML has improved over time, with an increased number of RIC-HCTs in patients with a Karnofsky performance status (KPS) ≥80. However, TRM remains high and the relapse rate has not improved over time. Multivariate analyses showed that a KPS ≥80 and complete remission at HCT were associated with less TRM and relapse, and better survival regardless of age ≥65 years. Accurate timing and prospective identification of patients at risk of TRM may aid the development of risk-adapted strategies for RIC-HCT in AML patients regardless of age.

The Prognostic Value of D-Dimer in De Novo Acute Myeloid Leukemia

BACKGROUND

The aim of this study was to evaluate the prognostic value of D-dimer in patients with newly diagnosed de novo non-M3 subtypes of acute myeloid leukemia (AML).

MATERIALS AND METHODS

We retrospectively analyzed the clinical data from 245 patients with newly diagnosed de novo non-M3 subtypes of AML at the Tongji Hospital from January 2010 to December 2014.

RESULTS

The comparison results indicated that the D-dimer values were higher in patients with AML with the following characteristics: WBC count ≥ 20 × 10(9)/L (2.20 versus 6.00, P = 0.001), percentage of bone marrow (BM) blasts ≥ 60% (2.06 versus 5.69, P = 0.003), and poor-risk stratification (P < 0.001). Cox univariate regression analysis showed that overall survival was negatively affected by the following factors: age > 60 years, poor-risk stratification, BM blast cell count ≥60%, and D-dimer ≥1μg/mL. Multivariate analysis showed that only age > 60 years (P < 0.001), BM blast cell counts ≥60% (P = 0.001) and D-dimer values ≥1μg/mL (P = 0.014) were independent adverse prognostic factors.

CONCLUSIONS

D-dimer ≥1μg/mL is related to high tumor burden and can be considered as an independent prognostic factor in patients with de novo non-M3 AML.

[Analyses of outcome and prognostic factors of adult acute myeloid leukemia patients received autologous hematopoietic stem cell transplantation]

目的

观察自体外周血造血干细胞移植（APBSCT）对于急性髓系白血病（AML）完全缓解期（CR）患者的疗效，并探讨影响APBSCT疗效的危险因素。

方法

对接受APBSCT治疗的全部55例AML患者的临床资料进行了回顾性研究，计算总生存（OS）率、无病生存（DFS）率、复发率，并对影响预后的各因素进行统计学分析。

结果

全部55例患者中，男35例，女20例，移植时中位年龄28(12~51）岁。移植后中位随访时间为1 091(20~3 024) d, 3年OS率、DFS率分别为77.1%（95% CI 71.2%~83.8%）、73.7%（95% CI 67.2%~80.3%）。移植后微小残留病（MRD）转阴<200 d组（27例）的DFS率高于≥200 d转阴组（8例）（88.9％对46.9%，P=0.042）；移植前MRD持续阴性患者3年DFS率为90.0%，MRD非持续阴性组为61.1%，但差异无统计学意义（P=0.090）。从确诊到MRD转阴时间为影响AML患者CR期行APBSCT预后的独立因素[RR=0.022(95% CI 0.001~0.604），P=0.024]。

结论

APBSCT是CR期AML患者的有效治疗方法。移植前监测MRD水平有助于判断APBSCT预后。

Hyper-recovery of platelets after induction therapy is a predictor of relapse-free survival in acute myeloid leukemia

We verified the association between standard clinical and laboratory variables and the risk of relapse in acute myeloid leukemia (AML), which led us to retrospectively examine the effect of regeneration of hematopoiesis in patients with newly diagnosed AML. We used data from 230 patients who obtained remission after cytarabine-based induction chemotherapy. Platelet counts ≥500 × 10⁹/L and hemoglobin levels ≥9 g/dL on day 28 after treatment initiation were significantly associated with relapse-free survival (RFS) rate, conferring respective multivariate risk ratios of 0.38 (95% CI: 0.18-0.79) and 0.60 (95% CI: 0.40-0.89) for the occurrence of relapse or death. No disease relapse occurred in core binding factor leukemia patients whose platelet counts recovered ≥500 × 10⁹/L at 28 days after therapy initiation. We conclude that regeneration of hematopoiesis, especially platelet hyper-recovery, after induction chemotherapy is a significant predictor of RFS in patients with AML.

Fusion genes in malignant neoplastic disorders of haematopoietic system

OBJECTIVES

The new World Health Organization's (WHO) classification of haematopoietic and lymphoid tissue neoplasms incorporating the recurrent fusion genes as the defining criteria for different haematopoietic malignant phenotypes is reviewed. The recurrent fusion genes incorporated in the new WHO's classification and other chromosomal rearrangements of haematopoietic and lymphoid tissue neoplasms are reviewed.

METHODOLOGY

Cytokines and transcription factors in haematopoiesis and leukaemic mechanisms are described. Genetic features and clinical implications due to the encoded chimeric neoproteins causing malignant haematopoietic disorders are reviewed.

RESULTS AND DISCUSSION

Multiple translocation partner genes are well known for leukaemia such as MYC, MLL, RARA, ALK, and RUNX1. With the advent of more sophisticated diagnostic tools and bioinformatics algorithms, an exponential growth in fusion genes discoveries is likely to increase.

CONCLUSION

Demonstration of fusion genes and their specific translocation breakpoints in malignant haematological disorders are crucial for understanding the molecular pathogenesis and clinical phenotype of cancer, determining prognostic indexes and therapeutic responses, and monitoring residual disease and relapse status.

Stem Cell Modeling of Core Binding Factor Acute Myeloid Leukemia

Even though clonally originated from a single cell, acute leukemia loses its homogeneity soon and presents at clinical diagnosis as a hierarchy of cells endowed with different functions, of which only a minority possesses the ability to recapitulate the disease. Due to their analogy to hematopoietic stem cells, these cells have been named “leukemia stem cells,” and are thought to be chiefly responsible for disease relapse and ultimate survival after chemotherapy. Core Binding Factor (CBF) Acute Myeloid Leukemia (AML) is cytogenetically characterized by either the t(8;21) or the inv(16)/t(16;16) chromosomal abnormalities, which, although being pathognomonic, are not sufficient per se to induce overt leukemia but rather determine a preclinical phase of disease when preleukemic subclones compete until the acquisition of clonal dominance by one of them. In this review we summarize the concepts regarding the application of the “leukemia stem cell” theory to the development of CBF AML; we will analyze the studies investigating the leukemogenetic role of t(8;21) and inv(16)/t(16;16), the proposed theories of its clonal evolution, and the role played by the hematopoietic niches in preserving the disease. Finally, we will discuss the clinical implications of stem cell modeling of CBF AML for the therapy of the disease.

Review: Aberrant EVI1 expression in acute myeloid leukaemia

Deregulated expression of the ecotropic virus integration site 1 (EVI1) gene is the molecular hallmark of therapy-resistant myeloid malignancies bearing chromosomal inv(3)(q21q26·2) or t(3;3)(q21;q26·2) [hereafter referred to as inv(3)/t(3;3)] abnormalities. EVI1 is a haematopoietic stemness and transcription factor with chromatin remodelling activity. Interestingly, the EVI1 gene also shows overexpression in 6-11% of adult acute myeloid leukaemia (AML) cases that do not carry any 3q aberrations. Deregulated expression of EVI1 is strongly associated with monosomy 7 and 11q23 abnormalities, which are known to be associated with poor response to treatment. However, EVI1 overexpression has been revealed as an important independent adverse prognostic marker in adult AML and defines distinct risk categories in 11q23-rearranged AML. Recently, important progress has been made in the delineation of the mechanism by which EVI1 becomes deregulated in inv(3)/t(3;3) as well as the cooperating mutations in this specific subset of AML with dismal prognosis.

Acute Myeloid Leukemia in Adolescents and Young Adults Treated in Pediatric and Adult Departments in the Nordic Countries

BACKGROUND

Studies on adolescents and young adults with acute lymphoblastic leukemia suggest better results when using pediatric protocols for adult patients, while corresponding data for acute myeloid leukemia (AML) are limited.

PROCEDURE

We investigated disease characteristics and outcome for de novo AML patients 10-30 years old treated in pediatric or adult departments. We included 166 patients 10-18 years of age with AML treated according to the pediatric NOPHO-protocols (1993-2009) compared with 253 patients aged 15-30 years treated in hematology departments (1996-2009) in the Nordic countries.

RESULTS

The incidence of AML was 4.9/million/year for the age group 10-14 years, 6.5 for 15-18 years, and 6.9 for 19-30 years. Acute promyelocytic leukemia (APL) was more frequent in adults and in females of all ages. Pediatric patients with APL had similar overall survival as pediatric patients without APL. Overall survival at 5 years was 60% (52-68%) for pediatric patients compared to 65% (58-70%) for adult patients. Cytogenetics and presenting white blood cell count were the only independent prognostic factors for overall survival. Age was not an independent prognostic factor.

CONCLUSIONS

No difference was found in outcome for AML patients age 10-30 years treated according to pediatric as compared to adult protocols.

Time-dependent effects of clinical predictors in unrelated hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation is a multifactorial process. Some of the predictors exhibit time-dependent effects. We present a systematic analysis and description of selected clinical predictors influencing outcome in a time-dependent manner based on an analysis of registry data from the German Registry for Stem Cell Transplantation. A total of 14,951 patients with acute myeloid leukemia, acute lymphocytic leukemia, myelodysplastic syndrome and non-Hodgkin lymphoma transplanted with peripheral blood stem cells or bone marrow grafts were included. Multivariate Cox regression models were tested for time-dependent effects within each diagnosis group. Predictors not satisfying the proportional hazards assumption were modeled in a time-dependent manner, extending the Cox regression models. Similar patterns occurred in all diagnosis groups. Patients with a poor Karnofsky performance score (<80) had a high risk for early mortality until day 139 following transplantation (HR 2.42, CI: 2.19-2.68; P<0.001) compared to patients with a good Karnofsky performance score (80-100). Afterwards the risk reduced to HR 1.43, CI: 1.25-1.63; P<0.001. A lower mortality risk was found for patients after conditioning treatment with reduced intensity until day 120 post transplant (HR: 0.81 CI: 0.75-0.88; P<0.001). After this, a slightly higher risk could be shown for these patients. Similarly, patients who had received a PBSC graft exhibited a significantly lower mortality risk until day 388 post transplantation (HR 0.79, CI: 0.73-0.85; P<0.001), reversing to a significantly higher risk afterwards (HR 1.23, CI: 1.08-1.40; P=0.002). Integrating time dependency in regression models allows a more accurate description and quantification of clinical predictors to be made, which may help in risk assessment and patient counseling.

Single monosomy as a relatively better survival factor in acute myeloid leukemia patients with monosomal karyotype

Monosomal karyotype (MK) defined by either ⩾2 autosomal monosomies or single monosomy with at least one additional structural chromosomal abnormality is associated with a dismal prognosis in patients with acute myeloid leukemia (AML). It was detected in 174 of 3041 AML patients in South Korean Registry. A total of 119 patients who had received induction therapy were finally analyzed to evaluate the predictive factors for a positive prognosis. On multivariate analysis, single monosomy, the absence of abn(17p), ⩾10% of cells with normal metaphase and the achievement of a complete remission (CR) after induction therapy were significant factors for more favorable outcomes. Especially, single monosomy remained as a significantly independent prognostic factor for superior survival in both patients who received allogeneic hematopoietic stem cell transplantation (allo-HSCT) in CR and who did not. Allo-HSCT in CR improved overall survival significantly only in patients with a single monosomy. Our results suggest that MK-AML may be biologically different according to the karyotypic subtype and that allo-HSCT in CR should be strongly recommended to patients with a single monosomy. For other patients, more prudent treatment strategies should be examined. Furthermore, the biological mechanism by which a single monosomy influences survival should be investigated.

Mild chronic graft-versus-host disease may alleviate poor prognosis associated with FLT3 internal tandem duplication for adult acute myeloid leukemia following allogeneic stem cell transplantation with myeloablative conditioning in first complete remission: a retrospective study

Internal tandem duplication (ITD) of the FLT3 gene (Fms-like tyrosine kinase 3) is the most commonly found mutation in acute myeloid leukemia (AML). The significance of FLT3-ITD at diagnosis was retrospectively estimated for allo-HSCT (allogeneic hematopoietic stem cell transplantation) outcomes in 140 patients, median age of 38, undergoing allo-HSCT after myeloablative conditioning in first complete remission of AML. FLT3-ITD was detected at AML diagnosis in 42/140 (30%) of included into this study patients. At 3 years, relapse incidence (RI) following allo-HSCT in AML patients with intermediate or normal karyotype was significantly higher in those FLT3-ITD positive than FLT3-ITD negative [52.9 vs. 20.4%, P = 0.002]. Additionally, patients with mild chronic graft-versus-host disease (cGvHD) had significantly lower RI compared to patients with moderate or severe grade cGvHD or those not experiencing cGvHD, respectively, 4.8 vs. 36.0 vs. 27.8%, P = 0.032. FLT3-ITD was harboring a poor prognosis in AML with intermediate or normal karyotype and significantly increased risk of relapse following allo-HSCT. It appears that allo-HSCT does not cure patients with FLT3-ITD, unless they develop symptoms of mild cGvHD and graft versus leukemia, which may decrease RI.

Identification of prognostic subgroups among acute myeloid leukemia patients with intermediate risk cytogenetics using a flow-cytometry-based assessment of ABC-transporter function

BACKGROUND

A median fluorescence intensity ratio (MFIR) which measures the efflux of mitoxantrone (an ATP Binding Cassette (ABC) transporter substrate) with and without ABC transporter inhibition correlates with expression of MDR1 and BCRP in acute myeloid leukemia (AML) blasts.

METHODS

This study evaluates the impacts of the MFIR on AML outcomes and its interaction with detection of the FLT3 ITD.

RESULTS

Among 200 newly diagnosed AML patients, an MFIR of ≥ 1.9 (MFIR+) was detected in 60 (30%) leukemic blast samples. In multivariate analysis, MFIR was an independent prognostic factor for response to induction chemotherapy (OR=7.2, P<0.00001), DFS (HR=2.3, P=0.004) and OS (HR=2.2, P=0.0005) with the main effect being in the 141 patients with intermediate risk cytogenetics. Among intermediate risk cytogenetics patients: MFIR+ outcomes were similar to unfavorable cytogenetic risk (CR, 53% vs. 52%, P=1.0; OS, 11 vs. 9 months, P=0.79). MFIR status can further stratify the prognostic risk for patients with or without FLT3 ITD mutation.

CONCLUSIONS

MFIR has value in predicting outcomes including DFS and OS as well as induction failure. This is particularly true for patients with intermediate risk cytogenetics and when combined with assessment for the FLT3-ITD mutation.

Characterization and prognostic features of secondary acute myeloid leukemia in a population-based setting: a report from the Swedish Acute Leukemia Registry

Patients with secondary acute myeloid leukemia (AML) often escape inclusion in clinical trials and thus, population-based studies are crucial for its accurate characterization. In this first large population-based study on secondary AML, we studied AML with an antecedent hematological disease (AHD-AML) or therapy-related AML (t-AML) in the population-based Swedish Acute Leukemia Registry. The study included 3,363 adult patients of which 2,474 (73.6%) had de novo AML, 630 (18.7%) AHD-AML, and 259 (7.7%) t-AML. Secondary AML differed significantly compared to de novo AML with respect to age, gender, and cytogenetic risk. Complete remission (CR) rates were significantly lower but early death rates similar in secondary AML. In a multivariable analysis, AHD-AML (HR 1.51; 95% CI 1.26-1.79) and t-AML (1.72; 1.38-2.15) were independent risk factors for poor survival. The negative impact of AHD-AML and t-AML on survival was highly age dependent with a considerable impact in younger patients, but without independent prognostic value in the elderly. Although patients with secondary leukemia did poorly with intensive treatment, early death rates and survival were significantly worse with palliative treatment. We conclude that secondary AML in a population-based setting has a striking impact on survival in younger AML patients, whereas it lacks prognostic value among the elderly patients.