The prognostic impact of 17p (p53) deletion in 2272 adults with acute myeloid leukemia

Evaluating targeted therapies in older patients with TP53-mutated AML

Mutation of thetumor suppressor gene, TP53 (tumor protein 53), occurs in up to 15% of all patients with acute myeloid leukemia (AML) and is enriched within specific clinical subsets, most notably in older adults, and including secondary AML cases arising from preceding myeloproliferative neoplasm (MPN), myelodysplastic syndrome (MDS), patients exposed to prior DNA-damaging, cytotoxic therapies. In all cases, these tumors have remained difficult to effectively treat with conventional therapeutic regimens. Newer approaches fortreatmentofTP53-mutated AML have shifted to interventions that maymodulateTP53 function, target downstream molecular vulnerabilities, target non-p53 dependent molecular pathways, and/or elicit immunogenic responses. This review will describe the basic biology of TP53, the clinical and biological patterns of TP53 within myeloid neoplasms with a focus on elderly AML patients and will summarize newer therapeutic strategies and current clinical trials.

Escape from T-cell-targeting immunotherapies in acute myeloid leukemia

ABSTRACT

Single-cell and spatial multimodal technologies have propelled discoveries of the solid tumor microenvironment (TME) molecular features and their correlation with clinical response and resistance to immunotherapy. Computational tools are incessantly being developed to characterize tumor-infiltrating immune cells and to model tumor immune escape. These advances have led to substantial research into T-cell hypofunctional states in the TME and their reinvigoration with T-cell-targeting approaches, including checkpoint inhibitors (CPIs). Until recently, we lacked a high-dimensional picture of the acute myeloid leukemia (AML) TME, including compositional and functional differences in immune cells between disease onset and postchemotherapy or posttransplantation relapse, and the dynamic interplay between immune cells and AML blasts at various maturation stages. AML subgroups with heightened interferon gamma (IFN-γ) signaling were shown to derive clinical benefit from CD123×CD3-bispecific dual-affinity retargeting molecules and CPIs, while being less likely to respond to standard-of-care cytotoxic chemotherapy. In this review, we first highlight recent progress into deciphering immune effector states in AML (including T-cell exhaustion and senescence), oncogenic signaling mechanisms that could reduce the susceptibility of AML cells to T-cell-mediated killing, and the dichotomous roles of type I and II IFN in antitumor immunity. In the second part, we discuss how this knowledge could be translated into opportunities to manipulate the AML TME with the aim to overcome resistance to CPIs and other T-cell immunotherapies, building on recent success stories in the solid tumor field, and we provide an outlook for the future.

Therapy-related myeloid neoplasms with single-hit TP53 mutations share the clinical, molecular, and survival characteristics of their multi-hit counterparts

Recent updates in the classification of myeloid neoplasms (MNs) recognize the poor prognostic impact of TP53 mutations, with particular emphasis on the TP53 allele status. Studies on the effect of TP53 allele status exclusively in therapy-related MNs (t-MNs) are lacking. We compared the clinicopathologic and survival characteristics of t-MNs with single-hit (SH) and multi-hit (MH) TP53 mutations. A total of 71 TP53-mutated t-MNs were included, including 56 (78.9%) MH and 15 (21.1%) SH. Both groups showed comparable genetic profiles with an excess of high-risk karyotypes and a paucity of other co-mutated genes. TP53 was the sole detectable mutation in 73.3% of SH and 75.0% of MH cases. The overall survival (OS) of SH TP53-mutated t-MNs was not significantly different from MH cases (median survival: 233 vs.273 days, p = 0.70). Our findings suggest that t-MNs with SH TP53 mutations share the poor prognostic and biologic profile of their MH counterparts.

Detection of novel PPP1R1B::STARD3 fusion transcript in acute myeloid leukemia: a case report

BACKGROUND

Acute myeloid leukemia (AML) is the second most common type of leukemia in children. Although prognostic and diagnostic tests of AML patients have improved, there is still a great demand for new reliable clinical biomarkers for AML. Read-through fusion transcripts (RTFTs) are complex transcripts of adjacent genes whose molecular mechanisms are poorly understood. This is the first report of the presence of the PPP1R1B::STARD3 fusion transcript in an AML patient. Here, we investigated the presence of PPP1R1B::STARD3 RTFT in a case of AML using paired-end RNA sequencing (RNA-seq).

CASE PRESENTATION

A Persian 12-year-old male was admitted to Dr. Sheikh Hospital of Mashhad, Iran, in September 2019 with the following symptoms, including fever, convulsions, hemorrhage, and bone pain. The patient was diagnosed with AML (non-M3-FAB subtype) based on cell morphologies and immunophenotypical features. Chromosomal analysis using the G-banding technique revealed t (9;22) (q34;q13).

CONCLUSIONS

Single-cell RNA sequencing (scRNA-seq) analysis suggested that the PPP1R1B promoter may be responsible for the PPP1R1B::STARD3 expression. Alterations in the level of lipid metabolites implicate cancer development, and this fusion can play a crucial role in the cholesterol movement in cancer cells. PPP1R1B::STARD3 may be considered a candidate for targeted therapies of the cholesterol metabolic and the PI3K/AKT signaling pathways involved in cancer development and progression.

Biologic and Clinical Characteristics of Isochromosome der(17)(q10)t(15;17) in Acute Promyelocytic Leukemia

INTRODUCTION

Acute promyelocytic leukemia (APL) is genetically characterized by the fusion of promyelocytic leukemia (PML) gene with retinoic acid receptor alpha (RARα) resulting from a t(15;17)(q24;q21) chromosomal translocation. An infrequent but recurrent finding in APL is the formation of an isochromosome of the derivative chromosome 17; ider(17)(q10)t(15;17) or ider(17q). This rearrangement in APL results in an additional copy of the PML-RARα fusion gene as well as loss of 17p/TP53. Due to the infrequent occurrence of the ider(17q), the prognostic impact of this genetic finding is not well known. Case Presentation(s): Here, we describe the clinical characteristics and outcomes of our case series of 5 patients with ider(17q) APL treated at the University of Maryland and Johns Hopkins University.

CONCLUSION

In our series, patients with APL with ider(17q) did not have a worse prognosis.

TP53-mutated acute myeloid leukemia and myelodysplastic syndrome: biology, treatment challenges, and upcoming approaches

Improved understanding of TP53 biology and the clinicopathological features of TP53-mutated myeloid neoplasms has led to the recognition of TP53-mutated acute myeloid leukemia/myelodysplastic syndrome (TP53m AML/MDS) as a unique entity, characterized by dismal outcomes following conventional therapies. Several clinical trials have investigated combinations of emerging therapies for these patients with the poorest molecular prognosis among myeloid neoplasms. Although some emerging therapies have shown improvement in overall response rates, this has not translated into better overall survival, hence the notion that p53 remains an elusive target. New therapeutic strategies, including novel targeted therapies, immune checkpoint inhibitors, and monoclonal antibodies, represent a shift away from cytotoxic and hypomethylating-based therapies, towards approaches combining non-immune and novel immune therapeutic strategies. The triple combination of azacitidine and venetoclax with either magrolimab or eprenetapopt have demonstrated safety in early trials, with phase III trials currently underway, and promising interim clinical results. This review compiles background on TP53 biology, available and emerging therapies along with their mechanisms of action for the TP53m disease entity, current treatment challenges, and recently published data and status of ongoing clinical trials for TP53m AML/MDS.

Accurate interpretation of p53 immunohistochemical patterns is a surrogate biomarker for TP53 alterations in large B-cell lymphoma

BACKGROUND

To clarify the relationship between p53 immunohistochemistry (IHC) staining and TP53 alterations (including mutations and deletions) in large B-cell lymphomas (LBCLs) and to explore the possibility of p53 IHC expression patterns as surrogate markers for TP53 alterations.

METHODS

A total of 95 patients diagnosed with LBCLs were selected, and paraffin samples were taken for TP53 gene sequencing, fluorescence in situ hybridization and p53 IHC staining. The results were interpreted by experienced pathologists and molecular pathologists.

RESULTS

Forty-three nonsynonymous TP53 mutations and p53 deletions were detected in 40 cases, whereas the remaining 55 cases had wild-type TP53 genes. The majority of TP53 mutations (34/43, 79.1%) occurred in exons 4-8, and R248Q was the most common mutation codon (4/43, 9.3%). The highest frequency single nucleotide variant was C > T (43.6%). p53 expression was interpreted as follows: Pattern A: p53 staining was positive in 0%-3% of tumor cells, Pattern B: p53 staining was positive in 4-65% of tumor cells, Pattern C: more than 65% of tumor cells were stained positive for p53. The p53 IHC expression patterns were associated with TP53 alterations. Gain of function variants and wild-type TP53 tended to exhibit type C and B p53 expression patterns, but loss of function variants were exclusively seen in type A cases. Additionally, interpretation of the staining by various observers produced significant reproducibility.

CONCLUSIONS

The p53 IHC expression patterns can be used to predict TP53 alterations and are reliable for diverse alteration types, making them possible surrogate biomarkers for TP53 alterations in LBCLs.

Optical Genome Mapping Reveals the Complex Genetic Landscape of Myeloma

Fluorescence in situ hybridization (FISH) on enriched CD138 plasma cells is the standard method for identification of clinically relevant genetic abnormalities in multiple myeloma. However, FISH is a targeted analysis that can be challenging due to the genetic complexity of myeloma. The aim of this study was to evaluate the potential of optical genome mapping (OGM) to detect clinically significant cytogenetic abnormalities in myeloma and to provide larger pangenomic information. OGM and FISH analyses were performed on CD138-purified cells of 20 myeloma patients. OGM successfully detected structural variants (SVs) (IGH and MYC rearrangements), copy number variants (CNVs) (17p/TP53 deletion, 1p deletion and 1q gain/amplification) and aneuploidy (gains of odd-numbered chromosomes, monosomy 13) classically expected with myeloma and led to a 30% increase in prognosis yield at our institution when compared to FISH. Despite challenges in the interpretation of OGM calls for CNV and aneuploidy losses in non-diploid genomes, OGM has the potential to replace FISH as the standard of care analysis in clinical settings and to efficiently change how we identify prognostic and predictive markers for therapies in the future. To our knowledge, this is the first study highlighting the feasibility and clinical utility of OGM in myeloma.

The presence of additional cytogenetic aberrations in chronic myeloid leukemia cells at the time of diagnosis or their appearance on tyrosine kinase inhibitor therapy predicts the imatinib treatment failure

Currently used treatment of CML dramatically improved the prognosis of disease. However, additional chromosome aberrations (ACA/Ph+) are still one of the adverse prognostic factors.

OBJECTIVES

evaluation of the impact of ACA/Ph+ appearance during disease outcome on the response to treatment. THE STUDY GROUP: consisted of 203 patients. The median time of follow-up was 72 months. ACA/Ph+ was found in 53 patients.

RESULTS

patients were divided into four groups: standard risk, intermediate, high and very high risk. When ACA/Ph+ presence was documented at diagnosis time the optimal response was observed in 41.2%, 25%, and 0% of pts with intermediate, high and very high risk, respectively. If ACA/Ph+ were detected during imatinib treatment the optimal response was in 4.8% of patients. The risk of blastic transformation for patients with standard risk, intermediate, high and very high risk was 2.7%, 18.4%, 20% and 50%, respectively.

CONCLUSIONS

the presence of ACA/Ph+ at diagnosis time or their appearance on therapy seems to be clinically relevant not only in terms of the risk of blastic transformation but also in terms of the treatment failure. Gathering patients with various karyotypes and their responses to treatment would allow to set better guidelines and predictions.

Entospletinib with decitabine in acute myeloid leukemia with mutant TP53 or complex karyotype: A phase 2 substudy of the Beat AML Master Trial

BACKGROUND

Patients with acute myeloid leukemia (AML) who have tumor protein p53 (TP53) mutations or a complex karyotype have a poor prognosis, and hypomethylating agents are often used. The authors evaluated the efficacy of entospletinib, an oral inhibitor of spleen tyrosine kinase, combined with decitabine in this patient population.

METHODS

This was a multicenter, open-label, phase 2 substudy of the Beat AML Master Trial (ClinicalTrials.gov identifier NCT03013998) using a Simon two-stage design. Eligible patients aged 60 years or older who had newly diagnosed AML with mutations in TP53 with or without a complex karyotype (cohort A; n = 45) or had a complex karyotype without TP53 mutation (cohort B; n = 13) received entospletinib 400 mg twice daily with decitabine 20 mg/m2 on days 1-10 every 28 days for up to three induction cycles, followed by up to 11 consolidation cycles, in which decitabine was reduced to days 1-5. Entospletinib maintenance was given for up to 2 years. The primary end point was complete remission (CR) and CR with hematologic improvement by up to six cycles of therapy.

RESULTS

The composite CR rates for cohorts A and B were 13.3% (95% confidence interval, 5.1%-26.8%) and 30.8% (95% confidence interval, 9.1%-61.4%), respectively. The median duration of response was 7.6 and 8.2 months, respectively, and the median overall survival was 6.5 and 11.5 months, respectively. The study was stopped because the futility boundary was crossed in both cohorts.

CONCLUSIONS

The combination of entospletinib and decitabine demonstrated activity and was acceptably tolerated in this patient population; however, the CR rates were low, and overall survival was short. Novel treatment strategies for older patients with TP53 mutations and complex karyotype remain an urgent need.

The Polyamine-Hypusine Circuit Controls an Oncogenic Translational Program Essential for Malignant Conversion in MYC-Driven Lymphoma

The MYC oncoprotein is activated in a broad spectrum of human malignancies and transcriptionally reprograms the genome to drive cancer cell growth. Given this, it is unclear if targeting a single effector of MYC will have therapeutic benefit. MYC activates the polyamine-hypusine circuit, which posttranslationally modifies the eukaryotic translation factor eIF5A. The roles of this circuit in cancer are unclear. Here we report essential intrinsic roles for hypusinated eIF5A in the development and maintenance of MYC-driven lymphoma, where the loss of eIF5A hypusination abolishes malignant transformation of MYC-overexpressing B cells. Mechanistically, integrating RNA sequencing, ribosome sequencing, and proteomic analyses revealed that efficient translation of select targets is dependent upon eIF5A hypusination, including regulators of G1-S phase cell-cycle progression and DNA replication. This circuit thus controls MYC's proliferative response, and it is also activated across multiple malignancies. These findings suggest the hypusine circuit as a therapeutic target for several human tumor types.

SIGNIFICANCE

Elevated EIF5A and the polyamine-hypusine circuit are manifest in many malignancies, including MYC-driven tumors, and eIF5A hypusination is necessary for MYC proliferative signaling. Not-ably, this circuit controls an oncogenic translational program essential for the development and maintenance of MYC-driven lymphoma, supporting this axis as a target for cancer prevention and treatment. See related commentary by Wilson and Klein, p. 248. This article is highlighted in the In This Issue feature, p. 247.

TP53 in AML and MDS: The new (old) kid on the block

MDS and AML are clonal hematopoietic stem cell disorders of increasing incidence, having a variable prognosis based, among others, on co-occurring molecular abnormalities. TP53 mutations are frequently detected in these myeloid neoplasms and portend a poor prognosis with known therapeutic resistance. This article provides a timely review of the complexity of TP53 alterations, providing updates in diagnosis and prognosis based on new 2022 International Consensus Classification (ICC) and World Health Organization (WHO) guidelines. The article addresses optimal testing strategies and reviews current and arising therapeutic approaches. While the treatment landscape for this molecular subgroup is under active development, further exploration is needed to optimize the care of this group of patients with unmet needs.

Checkpoint Inhibitors in Acute Myeloid Leukemia

The prognosis of acute myeloid leukemia (AML) remains unsatisfactory. Among the reasons for the poor response to therapy and high incidence of relapse, there is tumor cell immune escape, as AML blasts can negatively influence various components of the immune system, mostly weakening T-cells. Since leukemic cells can dysregulate immune checkpoints (ICs), receptor-based signal transductors that lead to the negative regulation of T-cells and, eventually, to immune surveillance escape, the inhibition of ICs is a promising therapeutic strategy and has led to the development of so-called immune checkpoint inhibitors (ICIs). ICIs, in combination with conventional chemotherapy, hypomethylating agents or targeted therapies, are being increasingly tested in cases of AML, but the results reported are often conflicting. Here, we review the main issues concerning the immune system in AML, the main pathways leading to immune escape and the results obtained from clinical trials of ICIs, alone or in combination, in newly diagnosed or relapsed/refractory AML.

Clinical characteristics and overall survival among acute myeloid leukemia patients with TP53 gene mutation or chromosome 17p deletion

Approximately 5% to 15% of acute myeloid leukemia (AML) patients have TP53 gene mutations (TP53m), which are associated with very poor outcomes. Adults (≥18 years) with a new AML diagnosis were included from a nationwide, de-identified, real-world database. Patients receiving first-line therapy were divided into three cohorts: venetoclax (VEN) + hypomethylating agents (HMAs; Cohort A), intensive chemotherapy (Cohort B), or HMA without VEN (Cohort C). A total of 370 newly diagnosed AML patients with TP53m (n = 124), chromosome 17p deletion (n = 166), or both (n = 80) were included. The median age was 72 years (range, 24-84); most were male (59%) and White (69%). Baseline bone marrow (BM) blasts were ≤30%, 31%-50%, and >50% in 41%, 24%, and 29% of patients in Cohorts A, B, and C, respectively. BM remission (<5% blasts) with first-line therapy was reported in 54% of patients (115/215) overall, and 67% (38/57), 62% (68/110), and 19% (9/48) for respective cohorts (median BM remission duration: 6.3, 6.9, and 5.4 months). Median overall survival (95% CI) was 7.4 months (6.0-8.8) for Cohort A, 9.4 months (7.2-10.4) for Cohort B, and 5.9 months (4.3-7.5) for Cohort C. There were no differences in survival by treatment type after adjusting for the effects of relevant covariates (Cohort A vs. C adjusted hazard ratio [aHR] = 0.9; 95% CI, 0.7-1.3; Cohort A vs. B aHR = 1.0; 95% CI, 0.7-1.5; and Cohort C vs. B aHR = 1.1; 95% CI, 0.8-1.6). Patients with TP53m AML have dismal outcomes with current therapies, demonstrating the high unmet need for improved treatments.

Neuroblastoma arises in early fetal development and its evolutionary duration predicts outcome

Neuroblastoma, the most frequent solid tumor in infants, shows very diverse outcomes from spontaneous regression to fatal disease. When these different tumors originate and how they evolve are not known. Here we quantify the somatic evolution of neuroblastoma by deep whole-genome sequencing, molecular clock analysis and population-genetic modeling in a comprehensive cohort covering all subtypes. We find that tumors across the entire clinical spectrum begin to develop via aberrant mitoses as early as the first trimester of pregnancy. Neuroblastomas with favorable prognosis expand clonally after short evolution, whereas aggressive neuroblastomas show prolonged evolution during which they acquire telomere maintenance mechanisms. The initial aneuploidization events condition subsequent evolution, with aggressive neuroblastoma exhibiting early genomic instability. We find in the discovery cohort (n = 100), and validate in an independent cohort (n = 86), that the duration of evolution is an accurate predictor of outcome. Thus, insight into neuroblastoma evolution may prospectively guide treatment decisions.

Survival of TP53-mutated acute myeloid leukemia patients receiving allogeneic stem cell transplantation after first induction or salvage therapy: results from the Consortium on Myeloid Malignancies and Neoplastic Diseases (COMMAND)

We conducted a multi-center study to analyze factors predicting survival among patients with TP53-mutated (m) AML receiving allogeneic hematopoietic stem cell transplant (allo-HSCT) in the recent era. Out of 370 TP53m AML patients, 68 (18%) patients were bridged to allo-HSCT. The median age of the patients was 63 years (range, 33-75), 82% of patients had complex cytogenetics and 66% of patients had multi-hit TP53m. Forty three percent received myeloablative conditioning and 57% received reduced intensity conditioning. The incidence of acute graft versus host disease (GVHD) was 37% and chronic GVHD was 44%. The median event-free survival (EFS) from the time of allo-HSCT was 12.4 months (95% CI: 6.24-18.55) and median overall survival (OS) was 24.5 months (95% CI: 21.80-27.25). In multivariate analysis utilizing variables that showed significance in univariate analysis, complete remission at day 100 post allo-HSCT retained significance for EFS (HR: 0.24, 95% CI: 0.10-0.57, p = 0.001) and OS (HR: 0.22, 95% CI: 0.10-0.50, p ≤ 0.001). Similarly, occurrence of chronic GVHD retained significance for EFS (HR: 0.21, 95% CI: 0.09-0.46, p ≤ 0.001) and OS (HR: 0.34, 95% CI: 0.15-0.75, p = 0.007). Our report suggests that allo-HSCT offers the best opportunity to improve long-term outcome among patients with TP53m AML.

Detection of TP53 Mutation in Acute Myeloid Leukemia by RT-PCR-Based Sanger Sequencing

The TP53 gene is known to be one of the most frequently mutated genes in various human cancers. In de novo acute myeloid leukemia (AML), TP53 has been found to be mutated in ~10% of patients. Although the frequency of TP53 mutations in AML is substantially lower compared to other human cancers, TP53 mutations in AML are associated with poor response to chemotherapy and poor outcomes. Therefore, assessment of TP53 status is critical in clinical routines and research studies. In this chapter, we described the use of conventional RT-PCR for rapid detection of TP53 mutations by Sanger sequencing. We use AML cells as an example but provide sufficient details for usage in other cell types.

Mechanisms of myeloid leukemogenesis: Current perspectives and therapeutic objectives

Acute myeloid leukemia (AML) is a heterogeneous hematopoietic neoplasm which results in clonal proliferation of abnormally differentiated hematopoietic cells. In this review, mechanisms contributing to myeloid leukemogenesis are summarized, highlighting aberrations of epigenetics, transcription factors, signal transduction, cell cycling, and the bone marrow microenvironment. The mechanisms contributing to AML are detailed to spotlight recent findings that convey clinical impact. The applications of current and prospective therapeutic targets are accentuated in addition to reviews of treatment paradigms stratified for each characteristic molecular lesion - with a focus on exploring novel treatment approaches and combinations to improve outcomes in AML.

Progress in Anticancer Drug Development Targeting Ubiquitination-Related Factors

Ubiquitination is extensively involved in critical signaling pathways through monitoring protein stability, subcellular localization, and activity. Dysregulation of this process results in severe diseases including malignant cancers. To develop drugs targeting ubiquitination-related factors is a hotspot in research to realize better therapy of human diseases. Ubiquitination comprises three successive reactions mediated by Ub-activating enzyme E1, Ub-conjugating enzyme E2, and Ub ligase E3. As expected, multiple ubiquitination enzymes have been highlighted as targets for anticancer drug development due to their dominant effect on tumorigenesis and cancer progression. In this review, we discuss recent progresses in anticancer drug development targeting enzymatic machinery components.

TP53 Mutant Acute Myeloid Leukemia: The Immune and Metabolic Perspective

TP53 mutated/deleted acute myeloid leukemia (AML) stands out as one of the poorest prognosis forms of acute leukemia with a median overall survival not reaching one year in most cases, even in selected cases when allogenic stem-cell transplantation is performed. This aggressive behavior relies on intrinsic chemoresistance of blast cells and on high rates of relapse. New insights into the biology of the disease have shown strong linkage between TP53 mutant AML, altered metabolic features and immunoregulation uncovering new scenarios and leading to possibilities beyond current treatment approaches. Furthermore, new targeted therapies acting on misfolded/dysfunctional p53 protein are under current investigation with the aim to improve outcomes. In this review, we sought to offer an insight into TP53 mutant AML current biology and treatment approaches, with a special focus on leukemia-associated immune and metabolic changes.

Differential prognostic impact of stratified additional chromosome abnormalities on disease progression among Malaysian chronic myeloid leukemia patients undergoing treatment with imatinib mesylate

The emergence of additional chromosome abnormalities (ACAs) in chronic myeloid leukemia (CML) patients during treatment with a tyrosine kinase inhibitor (TKI) regime is generally associated with resistance to treatment and a sign of disease progression to accelerated phase or blast phase. We report the type, frequency, and differential prognostic impact of stratified ACAs with treatment response in 251 Malaysian CML patients undergoing TKI therapy. ACAs were observed in 40 patients (15.9%) of which 7 patients (17.5%) showed ACAs at time of initial diagnosis whereas 33 patients (82.5%) showed ACAs during the course of IM treatment. In order to assess the prognostic significance, we stratified the CML patients with ACAs into four groups, group 1 (+8/+Ph), group 2 (hypodiploidy), group 3 (structural/complex abnormalities); group 4 (high-risk complex abnormalities), and followed up the disease outcome of patients. Group 1 and group 2 relatively showed good prognosis while patients in group 3 and group 4 had progressed or transformed to AP or blast phase with a median survival rate of 12 months after progression. Novel ACAs consisting of rearrangements involving chromosome 11 and chromosome 12 were found to lead to myeloid BP while ACAs involving the deletion of 7q or monosomy 7 led toward a lymphoid blast phase. There was no evidence of group 2 abnormalities (hypodiploidy) contributing to disease progression. Compared to group 1 abnormalities, CML patients with group 3 and group 4 abnormalities showed a higher risk for disease progression. We conclude that the stratification based on individual ACAs has a differential prognostic impact and might be a potential novel risk predictive system to prognosticate and guide the treatment of CML patients at diagnosis and during treatment.

Integrated genomic sequencing in myeloid blast crisis chronic myeloid leukemia (MBC-CML), identified potentially important findings in the context of leukemogenesis model

Chronic myeloid leukemia (CML) is a model of leukemogenesis in which the exact molecular mechanisms underlying blast crisis still remained unexplored. The current study identified multiple common and rare important findings in myeloid blast crisis CML (MBC-CML) using integrated genomic sequencing, covering all classes of genes implicated in the leukemogenesis model. Integrated genomic sequencing via Whole Exome Sequencing (WES), Chromosome-seq and RNA-sequencing were conducted on the peripheral blood samples of three CML patients in the myeloid blast crisis. An in-house filtering pipeline was applied to assess important variants in cancer-related genes. Standard variant interpretation guidelines were used for the interpretation of potentially important findings (PIFs) and potentially actionable findings (PAFs). Single nucleotide variation (SNV) and small InDel analysis by WES detected sixteen PIFs affecting all five known classes of leukemogenic genes in myeloid malignancies including signaling pathway components (ABL1, PIK3CB, PTPN11), transcription factors (GATA2, PHF6, IKZF1, WT1), epigenetic regulators (ASXL1), tumor suppressor and DNA repair genes (BRCA2, ATM, CHEK2) and components of spliceosome (PRPF8). These variants affect genes involved in leukemia stem cell proliferation, self-renewal, and differentiation. Both patients No.1 and No.2 had actionable known missense variants on ABL1 (p.Y272H, p.F359V) and frameshift variants on ASXL1 (p.A627Gfs*8, p.G646Wfs*12). The GATA2-L359S in patient No.1, PTPN11-G503V and IKZF1-R208Q variants in the patient No.3 were also PAFs. RNA-sequencing was used to confirm all of the identified variants. In the patient No. 3, chromosome sequencing revealed multiple pathogenic deletions in the short and long arms of chromosome 7, affecting at least three critical leukemogenic genes (IKZF1, EZH2, and CUX1). The large deletion discovered on the short arm of chromosome 17 in patient No. 2 resulted in the deletion of TP53 gene as well. Integrated genomic sequencing combined with RNA-sequencing can successfully discover and confirm a wide range of variants, from SNVs to CNVs. This strategy may be an effective method for identifying actionable findings and understanding the pathophysiological mechanisms underlying MBC-CML, as well as providing further insights into the genetic basis of MBC-CML and its management in the future.

Bone Marrow Fibrosis at Diagnosis and during the Course of Disease Is Associated with TP53 Mutations and Adverse Prognosis in Primary Myelodysplastic Syndrome

Simple Summary

To understand the role of bone marrow fibrosis and its molecular changes in myelodysplastic syndrome, we retrospectively analyzed data from 814 patients. Older age, lower hemoglobin, unfavorable karyotype and higher BM blast were more often observed in patients with moderate/severe fibrosis. Cases with bone marrow fibrosis had reduced overall survival. TP53, U2AF1 and KMT2D mutations were more frequent in patients with moderate/severe fibrosis. In addition, 15.1% of patients progressed to moderate/severe fibrosis during the follow-up interval. The clinical features, mutation landscape and prognosis of patients with progressed fibrosis were similar to those patients with moderate/severe fibrosis at diagnosis. We concluded that bone marrow fibrosis was associated with reduced overall survival in primary MDS and correlated with TP53 mutations both at the time of initial diagnosis and during the course of the disease.

Abstract

The prognostic significance of bone marrow fibrosis (MF) grade in patients with myelodysplastic syndrome (MDS) is still debated and the molecular changes remain unclear. In our large cohort, a normal reticulum was found in 211 (25.9%) patients, whereas MF1, MF2 and MF3 were detected in 478 (58.7%), 90 (11.1%) and 35 (4.3%) patients at initial diagnosis, respectively. Patients with MF often correlated with some poor prognostic characteristics, including older age, anemia, unfavorable karyotype, higher BM blast and a higher IPSS-R category. For the entire cohort, the median OS was not reached, 30, 16 and 15 months for patients with MF 0, 1, 2 and 3, respectively. After adjusting for IPSS-R, the hazard ratio for mortality was 1.56 (95% CI, 1.18–2.06) for patients with MF1, 2.29 (95% CI, 1.61–3.27) for patients with MF2 and 2.75 (95% CI, 1.69–4.49) for patients with MF3 compared with those with MF0. The mutational landscape of 370 patients showed that TP53, U2AF1 and KMT2D mutations were more frequent in patients with MF2-3. In addition, of the 408 patients with MF0-1, 62 patients (15.1%) progressed to MF2-3 during the follow-up interval. The clinical features, mutation landscape and prognosis of patients with progressed fibrosis were similar to those of patients with MF2-3 at diagnosis. We concluded that BM fibrosis (MF1, 2 and 3) was an adverse prognosis feature in primary MDS and correlated with TP53 mutations both at the time of initial diagnosis and during the course of the disease. Therefore, BM fibrosis should be included in the revised prognostic scoring system and carefully considered in treatment selection.

Are We Moving the Needle for Patients with TP53-Mutated Acute Myeloid Leukemia?

The currently available therapeutic options for patients with TP53-mutated acute myeloid leukemia (AML) are insufficient, as they translate to a median overall of only 6-9 months, and less than 10% of patients undergoing the most aggressive treatments, such as intensive induction therapy and allogeneic hematopoietic stem cell transplantation, will be cured. The lack of clear differences in outcomes with different treatments precludes the designation of a standard of care. Recently, there has been growing attention on this critical area of need by way of better understanding the biology of TP53 alterations and the disparities in outcomes among patients in this molecular subgroup, reflected in the development and testing of agents with novel mechanisms of action. Promising preclinical and efficacy data exist for therapies that are directed at the p53 protein rendered dysfunctional via mutation or that inhibit the CD47/SIRPα axis or other immune checkpoints such as TIM-3. In this review, we discuss recently attractive and emerging therapeutic agents, their preclinical rationale and the available clinical data as a monotherapy or in combination with the currently accepted backbones in frontline and relapsed/refractory settings for patients with TP53-mutated AML.

Independent prognostic significance of TP53 mutations in adult acute myeloid leukaemia with complex karyotype

INTRODUCTION

Adult acute myeloid leukaemia (AML) patients with complex karyotype (CK) generally have unfavourable outcomes. CK commonly co-exists with characteristic chromosomal and genetic abnormalities such as monosomal karyotype (MK), -17 or 17p- [abn(17p)] and TP53 mutations. Their individual prognostic significance needs to be clarified.

METHODS

Seventy-three adult CK-AML patients and eleven adult non-CK-AML patients with TP53 mutations (non-CK/TP53^mu ) who were diagnosed and received therapy at our institute were enrolled. One hundred and fifty-seven AML cases retrieved from the cancer genome atlas (TCGA) for validation.

RESULTS

Among CK-AML patients, those with TP53 mutations (CK/TP53^mu ) had significantly lower rates of 1-course induction complete remission (CR), 2-year relapse-free survival (RFS) and 2-year overall survival (OS) than those without TP53 mutations (CK/TP53^wt ); whereas, abn(17p) did not have the above impacts; MK was significantly associated with a lower 2-year OS rate but was not related to the rates of CR and RFS. Multivariate analysis showed that it were TP53 mutations and treating with chemotherapy alone but not MK and abn(17p) that independently predicted the adverse prognosis for RFS and OS in CK-AML. Furthermore, non-CK/TP53^mu patients showed similar rates of CR, RFS and OS to CK/TP53^mu patients. Validation using the TCGA cohort showed that CK/TP53^mu patients had a significantly lower 2-year OS rate than CK/TP53^wt patients, whereas abn(17p) and MK did not impact OS; the 2-year OS rate of patients with CK/TP53^wt was similar to that of patients with intermediate-risk cytogenetics.

CONCLUSION

Adult CK-AML patients have varied risks and TP53 mutations seem to be an independent adverse prognostic factor.

The prognostic impact of cigarette smoking on survival in acute myeloid leukemia with TP53 mutations and/or 17p deletions

Cigarette smoking has been associated with increased risk of developing acute myeloid leukemia (AML) in adults. There is limited data on the impact of smoking in AML patients with certain cytogenetic abnormalities. The aim of this study is to assess whether cigarette smoking affected the survival outcome of patients with newly diagnosed AML with TP53 alterations. We conducted a retrospective study of patients who were diagnosed with AML at the Thomas Jefferson Hospital with presence of TP53 mutations and/or 17p deletions. Patients' sex, age, race, smoking status (ever vs. never), cytogenetics, mutational profile, induction regimen, and induction response were analyzed. A total of 102 patients were included in the study with a median follow-up of 27.8 months. Among 100 patients who had documentation of smoking status, 59 patients (59%) were ever-smokers and 41 (41%) were never-smokers. Kaplan-Meier survival analysis showed that never-smokers did not differ in overall survival (OS) when compared to ever-smokers (P = 0.34). Univariate analysis revealed that age and cytogenetics had a statistically significant impact on survival. In multivariate analysis incorporating sex, age, race, smoking status, cytogenetics, and induction regimen as covariates, cytogenetics and induction regimen were independent prognostic factors for OS. In summary, no significant difference in OS was found between ever- and never-smokers in AML patients with TP53 alterations. Additional studies are needed to examine the prognostic impact of cigarette smoking in AML with specific cytogenetic abnormalities.

A unique role of p53 haploinsufficiency or loss in the development of acute myeloid leukemia with FLT3-ITD mutation

With an incidence of ~50%, the absence or reduced protein level of p53 is much more common than TP53 mutations in acute myeloid leukemia (AML). AML with FLT3-ITD (internal tandem duplication) mutations has an unfavorable prognosis and is highly associated with wt-p53 dysfunction. While TP53 mutation in the presence of FLT3-ITD does not induce AML in mice, it is not clear whether p53 haploinsufficiency or loss cooperates with FLT3-ITD in the induction of AML. Here, we generated FLT3-ITD knock-in; p53 knockout (heterozygous and homozygous) double-transgenic mice and found that both alterations strongly cooperated in the induction of cytogenetically normal AML without increasing the self-renewal potential. At the molecular level, we found the strong upregulation of Htra3 and the downregulation of Lin28a, leading to enhanced proliferation and the inhibition of apoptosis and differentiation. The co-occurrence of Htra3 overexpression and Lin28a knockdown, in the presence of FLT3-ITD, induced AML with similar morphology as leukemic cells from double-transgenic mice. These leukemic cells were highly sensitive to the proteasome inhibitor carfilzomib. Carfilzomib strongly enhanced the activity of targeting AXL (upstream of FLT3) against murine and human leukemic cells. Our results unravel a unique role of p53 haploinsufficiency or loss in the development of FLT3-ITD + AML.

Association Between TP53 Mutation and Prognosis in Wilms Tumor: A Meta-Analysis

BackgroundTP53 mutation has been suggested to have prognostic value for patients with Wilms tumor (WT), but the results are still controversial. Methods: Relevant studies published until August 1, 2019 were identified by searching PubMed, EMBASE and Cochrane Library. A random-effect model was performed to assess pooled data. Begg's and Egger's test were used to evaluate the potential publication bias. Sensitivity analysis was used to evaluate the stability of results. Results: A total of seven eligible articles were included. There was no significant difference in the risk of death among patients with WT with different TP53 mutation status (odds ratio [OR] = 3.09, 95% confidence interval[CI]: 0.81-11.84). Combined hazard ratio (HR) suggested that TP53 mutation had an unfavorable impact on overall survival (OS) (HR = 4.17, 95% CI: 1.97-6.36) and disease-free survival (DFS) (HR = 2.23, 95% CI: 1.29-3.17) in WT. Conclusions: This meta-analysis demonstrates that TP53 mutations are associated with poorer prognosis in WT.

Development of TP53 mutations over the course of therapy for acute myeloid leukemia

TP53 mutations in acute myeloid leukemia (AML) are associated with resistance to standard treatments and dismal outcomes. The incidence and prognostic impact of the emergence of newly detectable TP53 mutations over the course of AML therapy has not been well described. We retrospectively analyzed 200 patients with newly diagnosed TP53 wild type AML who relapsed after or were refractory to frontline therapy. Twenty-nine patients (15%) developed a newly detectable TP53 mutation in the context of relapsed/refractory disease. The median variant allelic frequency (VAF) was 15% (range, 1.1%-95.6%). TP53 mutations were more common after intensive therapy versus lower-intensity therapy (23% vs. 10%, respectively; p = 0.02) and in patients who had undergone hematopoietic stem cell transplant versus those who had not (36% vs. 12%, respectively; p = 0.005). Lower TP53 VAF was associated with an increased likelihood of complete remission (CR) or CR with incomplete hematologic recovery (CRi) compared to higher TP53 VAF (CR/CRi rate of 41% for VAF < 20% vs. 13% for VAF ≥ 20%, respectively). The median overall survival (OS) after acquisition of TP53 mutation was 4.6 months, with a 1-year OS rate of 19%. TP53 VAF at relapse was significantly associated with OS; the median OS of patients with TP53 VAF ≥ 20% was 3.5 months versus 6.1 months for those with TP53 VAF < 20% (p < 0.05). In summary, new TP53 mutations may be acquired throughout the course of AML therapy. Sequential monitoring for TP53 mutations is likely to be increasingly relevant in the era of emerging TP53-targeting therapies for AML.

TP53 in Acute Myeloid Leukemia: Molecular Aspects and Patterns of Mutation

Mutation of the tumor suppressor gene, TP53, is associated with abysmal survival outcomes in acute myeloid leukemia (AML). Although it is the most commonly mutated gene in cancer, its occurrence is observed in only 5–10% of de novo AML, and in 30% of therapy related AML (t-AML). TP53 mutation serves as a prognostic marker of poor response to standard-of-care chemotherapy, particularly in t-AML and AML with complex cytogenetics. In light of a poor response to traditional chemotherapy and only a modest improvement in outcome with hypomethylation-based interventions, allogenic stem cell transplant is routinely recommended in these cases, albeit with a response that is often short lived. Despite being frequently mutated across the cancer spectrum, progress and enthusiasm for the development of p53 targeted therapeutic interventions is lacking and to date there is no approved drug that mitigates the effects of TP53 mutation. There is a mounting body of evidence indicating that p53 mutants differ in functionality and form from typical AML cases and subsequently display inconsistent responses to therapy at the cellular level. Understanding this pathobiological activity is imperative to the development of effective therapeutic strategies. This review aims to provide a comprehensive understanding of the effects of TP53 on the hematopoietic system, to describe its varying degree of functionality in tumor suppression, and to illustrate the need for the adoption of personalized therapeutic strategies to target distinct classes of the p53 mutation in AML management.

Clinico-genomic profiling and clonal dynamic modeling of TP53-aberrant myelodysplastic syndrome and acute myeloid leukemia

TP53-aberrant myelodysplastic syndrome and acute myeloid leukemia have dismal outcomes. Here, we define the clinico-genomic landscape of TP53 disruptions in 40 patients and employ clonal dynamic modeling to map the mutational hierarchy against clinical outcomes. Most TP53 mutations (45.2%) localized to the L3 loop or LSH motif of the DNA-binding domain. TP53 disruptions had high co-occurrence with mutations in epigenetic regulators, spliceosome machinery, and cohesin complex and low co-occurrence with mutations in proliferative signaling genes. Ancestral and descendant TP53 mutations constituted measurable residual disease and fueled relapse. High mutant TP53 gene dosage predicted low durability of remission. The median overall survival (OS) was 280 days. Hypomethylating agent-based therapy served as an effective bridge to transplant, leading to improved median OS compared to patients who did not receive a transplant (14.7 vs. 5.1 months). OS was independent of the genomic location of TP53 disruption, which has implications for rational therapeutic design.

Can the New and Old Drugs Exert an Immunomodulatory Effect in Acute Myeloid Leukemia?

Simple Summary

The advent of novel immunotherapeutic strategies has revealed the importance of immune dysregulation and of a tolerogenic microenvironment for acute myeloid leukemia (AML) fitness. We reviewed the “off-target” effects on the immune system of different drugs used in the treatment of AML to explore the advantages of this unexpected interaction.

Abstract

Acute myeloid leukemia (AML) is considered an immune-suppressive neoplasm capable of evading immune surveillance through cellular and environmental players. Increasing knowledge of the immune system (IS) status at diagnosis seems to suggest ever more attention of the crosstalk between the leukemic clone and its immunologic counterpart. During the last years, the advent of novel immunotherapeutic strategies has revealed the importance of immune dysregulation and suppression for leukemia fitness. Considering all these premises, we reviewed the “off-target” effects on the IS of different drugs used in the treatment of AML, focusing on the main advantages of this interaction. The data reported support the idea that a successful therapeutic strategy should consider tailored approaches for performing leukemia eradication by both direct blasts killing and the engagement of the IS.

Outcomes in patients with newly diagnosed TP53-mutated acute myeloid leukemia with or without venetoclax-based therapy

BACKGROUND

Venetoclax (VEN) in combination with a hypomethylating agent (HMA) has become the standard of care for patients aged >75 years and for those not eligible for intensive chemotherapy who have newly diagnosed acute myeloid leukemia (AML). The benefit of VEN-based therapy in patients who have newly diagnosed AML with mutations in the TP53 gene (TP53^mut ) over standard therapy is undefined.

METHODS

In this single-institutional, retrospective analysis, the authors assessed the clinical outcomes of 238 patients with newly diagnosed TP53^mut AML and compared the clinical characteristics, response to different therapies, and outcomes of those who received VEN-based (n = 58) and non-VEN-based (n = 180) regimens.

RESULTS

Patients who received VEN-based regimens were older (aged >65 years: 81% vs 65%; P = .02) and had higher response rates (complete remission, 43% vs 32%; P = .06) than those who received non-VEN-based regimens. Compared with patients who received non-VEN-based regimens, no difference in overall survival (median, 6.6 vs 5.7 months; P = .4) or relapse-free survival (median, 4.7 vs 3.5 months; P = .43) was observed in those who received VEN-based regimens, regardless of age or intensity of treatment.

CONCLUSIONS

The addition of VEN to standard treatment regimens did not improve outcomes in younger or older patients who had TP53^mut AML. These data highlight the need for novel therapies beyond VEN to improve the outcome of patients with TP53^mut AML.

Acute Myeloid Leukemia: Historical Perspective and Progress in Research and Therapy Over 5 Decades

With the Food and Drug Administration approval of 9 agents for different acute myeloid leukemia (AML) indications, the prognosis and management of AML is evolving rapidly. Herein, we review the important milestones in the history of AML research and therapy, discuss insights regarding prognostic assessment and prediction of treatment outcome, detail practical supportive care measures, and summarize the current treatment landscape and areas of evolving research.

TP53 abnormalities correlate with immune infiltration and associate with response to flotetuzumab immunotherapy in AML

Somatic TP53 mutations and 17p deletions with genomic loss of TP53 occur in 37% to 46% of acute myeloid leukemia (AML) with adverse-risk cytogenetics and correlate with primary induction failure, high risk of relapse, and dismal prognosis. Herein, we aimed to characterize the immune landscape of TP53-mutated AML and determine whether TP53 abnormalities identify a patient subgroup that may benefit from immunotherapy with flotetuzumab, an investigational CD123 × CD3 bispecific dual-affinity retargeting antibody (DART) molecule. The NanoString PanCancer IO360 assay was used to profile 64 diagnostic bone marrow (BM) samples from patients with TP53-mutated (n = 42) and TP53-wild-type (TP53-WT) AML (n = 22) and 45 BM samples from patients who received flotetuzumab for relapsed/refractory (R/R) AML (15 cases with TP53 mutations and/or 17p deletion). The comparison between TP53-mutated and TP53-WT primary BM samples showed higher expression of IFNG, FOXP3, immune checkpoints, markers of immune senescence, and phosphatidylinositol 3-kinase-Akt and NF-κB signaling intermediates in the former cohort and allowed the discovery of a 34-gene immune classifier prognostic for survival in independent validation series. Finally, 7 out of 15 patients (47%) with R/R AML and TP53 abnormalities showed complete responses to flotetuzumab (<5% BM blasts) on the CP-MGD006-01 clinical trial (NCT #02152956) and had significantly higher tumor inflammation signature, FOXP3, CD8, inflammatory chemokine, and PD1 gene expression scores at baseline compared with nonresponders. Patients with TP53 abnormalities who achieved a complete response experienced prolonged survival (median, 10.3 months; range, 3.3-21.3 months). These results encourage further study of flotetuzumab immunotherapy in patients with TP53-mutated AML.

The potential role of nucleophosmin (NPM1) in the development of cancer

Nucleophosmin (NPM1) is a well-known nucleocytoplasmic shuttling protein that performs several cellular functions such as ribosome biogenesis, chromatin remodeling, genomic stability, cell cycle progression, and apoptosis. NPM1 has been identified to be necessary for normal cellular functions, and its altered regulation by overexpression, mutation, translocation, loss of function, or sporadic deletion can lead to cancer and tumorigenesis. In this review, we focus on the gene and protein structure of NPM1 and its physiological roles. Finally, we discuss the association of NPM1 with various types of cancer including solid tumors and leukemia.

Haematologic malignancies with unfavourable gene mutations benefit from donor lymphocyte infusion with/without decitabine for prophylaxis of relapse after allogeneic HSCT: A pilot study

Relapse is the main cause of treatment failure for leukaemia patients with unfavourable gene mutations who receive allogeneic haematopoietic stem cell transplantation (allo‐HSCT). There is no consensus on the indication of donor lymphocyte infusion (DLI) for prophylaxis of relapse after allo‐HSCT. To evaluate the tolerance and efficacy of prophylactic DLI in patients with unfavourable gene mutations such as FLT3‐ITD, TP53, ASXL1, DNMT3A or TET2, we performed a prospective, single‐arm study. Prophylactic use of decitabine followed by DLI was planned in patients with TP53 or epigenetic modifier gene mutations. The prophylaxis was planned in 46 recipients: it was administered in 28 patients and it was not administered in 18 patients due to contraindications. No DLI‐associated pancytopenia was observed. The cumulative incidences of grade II–IV and III–IV acute graft‐versus‐host disease (GVHD) at 100 days post‐DLI were 25.8% and 11.0%, respectively. The rates of chronic GVHD, non‐relapse mortality and relapse at 3 years post‐DLI were 21.6%, 25.0% and 26.1%, respectively. The 3‐year relapse‐free survival and overall survival (OS) rates were 48.9% and 48.2%, respectively. Acute GVHD (HR: 2.30, p = 0.016) and relapse (HR: 2.46, p = 0.003) after DLI were independently associated with inferior OS. Data in the current study showed the feasibility of prophylactic DLI with/without decitabine in the early stage after allo‐HSCT in patients with unfavourable gene mutations.

Acute myeloid leukemia: Treatment and research outlook for 2021 and the MD Anderson approach

The unraveling of the pathophysiology of acute myeloid leukemia (AML) has resulted in rapid translation of the information into clinical practice. After more than 40 years of slow progress in AML research, the US Food and Drug Administration has approved nine agents for different AML treatment indications since 2017. In this review, we detail the progress that has been made in the research and treatment of AML, citing key publications related to AML research and therapy in the English literature since 2000. The notable subsets of AML include acute promyelocytic leukemia (APL), core-binding factor AML (CBF-AML), AML in younger patients fit for intensive chemotherapy, and AML in older/unfit patients (usually at the age cutoff of 60-70 years). We also consider within each subset whether the AML is primary or secondary (therapy-related, evolving from untreated or treated myelodysplastic syndrome or myeloproliferative neoplasm). In APL, therapy with all-trans retinoic acid and arsenic trioxide results in estimated 10-year survival rates of ≥80%. Treatment of CBF-AML with fludarabine, high-dose cytarabine, and gemtuzumab ozogamicin (GO) results in estimated 10-year survival rates of ≥75%. In younger/fit patients, the "3+7" regimen (3 days of daunorubicin + 7 days of cytarabine) produces less favorable results (estimated 5-year survival rates of 35%; worse in real-world experience); regimens that incorporate high-dose cytarabine, adenosine nucleoside analogs, and GO are producing better results. Adding venetoclax, FLT3, and IDH inhibitors into these regimens has resulted in encouraging preliminary data. In older/unfit patients, low-intensity therapy with hypomethylating agents (HMAs) and venetoclax is now the new standard of care. Better low-intensity regimens incorporating cladribine, low-dose cytarabine, and other targeted therapies (FLT3 and IDH inhibitors) are emerging. Maintenance therapy now has a definite role in the treatment of AML, and oral HMAs with potential treatment benefits are also available. In conclusion, AML therapy is evolving rapidly and treatment results are improving in all AML subsets as novel agents and strategies are incorporated into traditional AML chemotherapy. LAY SUMMARY: Ongoing research in acute myeloid leukemia (AML) is progressing rapidly. Since 2017, the US Food and Drug Administration has approved 10 drugs for different AML indications. This review updates the research and treatment pathways for AML.

Acute myeloid leukemia: current progress and future directions

Progress in the understanding of the biology and therapy of acute myeloid leukemia (AML) is occurring rapidly. Since 2017, nine agents have been approved for various indications in AML. These included several targeted therapies like venetoclax, FLT3 inhibitors, IDH inhibitors, and others. The management of AML is complicated, highlighting the need for expertise in order to deliver optimal therapy and achieve optimal outcomes. The multiple subentities in AML require very different therapies. In this review, we summarize the important pathophysiologies driving AML, review current therapies in standard practice, and address present and future research directions.

TP53 Mutations in Acute Myeloid Leukemia: Still a Daunting Challenge?

TP53 is a key tumor suppressor gene with protean functions associated with preservation of genomic balance, including regulation of cellular senescence, apoptotic pathways, metabolism functions, and DNA repair. The vast majority of de novo acute myeloid leukemia (AML) present unaltered TP53 alleles. However, TP53 mutations are frequently detected in AML related to an increased genomic instability, such as therapy‐related (t-AML) or AML with myelodysplasia-related changes. Of note, TP53 mutations are associated with complex cytogenetic abnormalities, advanced age, chemoresistance, and poor outcomes. Recent breakthroughs in AML research and the development of targeted drugs directed at specific mutations have led to an explosion of novel treatments with different mechanisms. However, optimal treatment strategy for patients harboring TP53 mutations remains a critical area of unmet need. In this review, we focus on the incidence and clinical significance of TP53 mutations in de novo and t-AML. The influence of these alterations on response and clinical outcomes as well as the current and future therapeutic perspectives for this hardly treatable setting are discussed.

Prognostic Impact of Cytogenetic Evolution on the Outcome of Allogeneic Stem Cell Transplantation in Patients with Acute Myeloid Leukemia in Nonremission: A Single-Institute Analysis of 212 Recipients

Recent progress in genetic analysis technology has helped researchers understand the pathogenesis of acute myeloid leukemia (AML). Considering this progress, AML karyotype is still one of the most significant prognostic factors that provides risk-adapted treatment approaches. Karyotype changes during treatment have been observed at times, but their prognostic impact is sparse, especially on allogeneic stem cell transplantation (allo-SCT). Here, we retrospectively investigated the effect of chromosomal changes between diagnosis and pretransplantation on the prognosis of allo-SCT by analyzing the outcomes of 212 consecutive patients who underwent allo-SCT for the first time at Toranomon Hospital, Tokyo, Japan, between 2008 and 2018. Cytogenetic abnormalities at diagnosis and pretransplantation were categorized based on the 2017 European Leukemia Net risk stratification. Genetic abnormalities such as FLT3-ITD and NPM1 were not considered in this study due to lack of genetic information in most patients. We defined cytogenetic evolution as chromosomal changes classified from lower category to higher category. Seventeen patients (8%) had cytogenetic evolution between diagnosis and pretransplantation, and they showed a significantly worse relapse rate than those who were categorized in the intermediate group based on the karyotype at diagnosis (3-year confidence interval [CI] of relapse, 57.4% versus 24.9%; P < .01). In multivariate analysis, cytogenetic evolution before allo-SCT had a significant impact on the CI of relapse (hazard ratio [HR], 3.89; CI, 1.75 to 8.67; P < .01), as well as the high score of the hematopoietic cell transplantation-specific comorbidity index (HR, 0.54; CI, 0.31 to 0.94; P = .03), but had no significant impact on overall survival or nonrelapse mortality. These results indicate that cytogenetic evolution has a significant impact after allo-SCT and should be considered during AML treatment.

An expert overview of emerging therapies for acute myeloid leukemia: novel small molecules targeting apoptosis, p53, transcriptional regulation and metabolism

INTRODUCTION

Acute myeloid leukemia (AML) is an aggressive malignancy of clonal myeloid precursor cells. Curative therapy has classically involved the use of intensive induction chemotherapy followed by consolidation with additional chemotherapy or allogeneic hematopoietic stem cell transplant. For many patients, such an approach is prohibitive because of high treatment-related toxicities. Advancements in the molecular understanding of AML have led to the introduction of new targeted therapies that are changing the treatment landscape for AML.

AREAS COVERED

We review emerging small molecule inhibitors that have shown preclinical efficacy for the treatment of AML. The compounds discussed affect apoptosis, p53-mediated interactions, transcriptional regulation, and cellular metabolism. We performed a literature search of PubMed and primarily included relevant sources published from 2000 to the present, though earlier sources are also referenced.

EXPERT OPINION

Most clinical trials for AML currently employ novel targeted therapies that demonstrate promising activity in preclinical models. We anticipate that new small molecule inhibitors will continue to enter the clinical realm and alter the treatment paradigm for AML. In a field where clinical advancement was comparatively slow for many years, it appears that we are now starting to see the rapid growth borne out of the deepening molecular understanding of AML.

Loss of TRP53 (p53) accelerates tumorigenesis and changes the tumor spectrum of SJL/J mice

Known as the guardian of the genome, transformation-related protein 53 (TRP53) is a well -known tumor suppressor. Here, we describe a novel TRP53 deficient mouse model on a tumor prone background—SJL/J mice. The absence of TRP53 (TRP53 nullizygosity) leads to a shift in the tumor spectrum from a non-Hodgkin’s-like disease to thymic lymphomas and testicular teratomas at a very rapid tumor onset averaging ~12 weeks of age. In haplotype studies, comparing tumor prone versus tumor resistant Trp53 null mouse strains, we found that other tumor suppressor, DNA repair and/or immune system genes modulate tumor incidence in TRP53 null strains, suggesting that even a strong tumor suppressor such as TRP53 is modulated by genetic background. Due to their rapid development of tumors, the SJL/J TRP53 null mice generated here can be used as an efficient chemotherapy or immunotherapy screening mouse model.

Monosomal karyotype and chromosome 17p loss or TP53 mutations in decitabine-treated patients with acute myeloid leukemia

TP53 aberrations reportedly predict favorable responses to decitabine (DAC) in acute myeloid leukemia (AML). We evaluated clinical features and outcomes associated with chromosome 17p loss or TP53 gene mutations in older, unfit DAC-treated AML patients in a phase II trial. Of 178 patients, 25 had loss of 17p in metaphase cytogenetics; 24 of these had a complex (CK+) and 21 a monosomal karyotype (MK+). In analyses in all patients and restricted to CK+ and MK+ patients, 17p loss tended to associate with higher rates of complete remission (CR), partial remission (PR), or antileukemic effect (ALE). Despite favorable response rates, there was no significant OS difference between patients with or without loss of 17p in the entire cohort or in the CK+ and MK+ cohort. TP53 mutations were identified in eight of 45 patients with material available. Five of the eight TP53-mutated patients had 17p loss. TP53-mutated patients had similar rates of CR/PR/ALE but shorter OS than those with TP53 wild type (P = 0.036). Moreover, patients with a subclone based on mutation data had shorter OS than those without (P = 0.05); only one patient with TP53-mutated AML had a subclone. In conclusion, 17p loss conferred a favorable impact on response rates, even among CK+ and MK+ patients that however could not be maintained. The effect of TP53 mutations appeared to be different; however, patient numbers were low. Future research needs to further dissect the impact of the various TP53 aberrations in HMA-based combination therapies. The limited duration of favorable responses to HMA treatment in adverse-risk genetics AML should prompt physicians to advance allografting for eligible patients in a timely fashion.

Tumor protein 53 mutations in acute myeloid leukemia: conventional induction chemotherapy or novel therapeutics

PURPOSE OF REVIEW

Tumor protein 53 (TP53) protein is involved in fundamental processes of cancer, aging, and DNA repair. Thus, TP53 dysfunction is implicated in malignant processes and remains the most commonly mutated gene in cancer but represents a relatively small proportion in acute myeloid leukemia (AML). Patients with TP53-mutated AML attain inferior responses to therapy resulting in poor overall outcomes.

RECENT FINDINGS

Traditional treatment approaches with conventional chemotherapy yields suboptimal responses for patients with TP53 mutant AML compared with wildtype TP53. In recent years, there is increasing interest in understanding the role and underlying biology of TP53 mutations in AML with efforts to harness the physiological tumor suppressive function of TP53 protein. Novel combination and targeted therapies may contribute to improved outcomes; however, responses to therapy may be short-lived and ongoing research is indicated to evaluate relapse-risk reduction strategies. These patients may benefit from consideration of enrollment in clinical trials or lower intensity therapy approaches in lieu of intensive chemotherapy.

SUMMARY

Pharmacological treatments targeting the TP53 pathway in addition to novel emerging therapeutics and immunotherapy-based approaches hold promise for treatment of TP53 mutant AML.

How we treat older patients with acute myeloid leukaemia

After decades when intensive chemotherapy remained the only effective anti-acute myeloid leukaemia (AML) treatment, a torrent of novel, less toxic agents are about to revolutionise AML therapy. Prolonged remissions with good quality of life become achievable for many patients previously considered only for palliative care because they could not tolerate intensive therapy. As treatment options multiply, the importance of genetic profile is recognised, even for advanced-age patients for whom cure is unlikely. With lack of randomised comparative trials for most treatment regimens, one can only extrapolate data from existing studies to make evidence-based decisions. We herein present seven common clinical scenarios illustrating the complexity of treating older AML patients and describe our approach to their management. In each case, up-to-date data on relevant agents to be offered to a particular patient are discussed. The current review is limited to the drugs, available and approved in the Western world and many promising agents, still under investigation, are not discussed.

Whole genome analysis identifies the association of TP53 genomic deletions with lower survival in Stage III colorectal cancer

DNA copy number aberrations (CNA) are frequently observed in colorectal cancers (CRC). There is an urgent need for CNA-based biomarkers in clinics,. n For Stage III CRC, if combined with imaging or pathologic evidence, these markers promise more precise care. We conducted this Stage III specific biomarker discovery with a cohort of 134 CRCs, and with a newly developed high-efficiency CNA profiling protocol. Specifically, we developed the profiling protocol for tumor-normal matched tissue samples based on low-coverage clinical whole-genome sequencing (WGS). We demonstrated the protocol’s accuracy and robustness by a systematic benchmark with microarray, high-coverage whole-exome and -genome approaches, where the low-coverage WGS-derived CNA segments were highly accordant (PCC >0.95) with those derived from microarray, and they were substantially less variable if compared to exome-derived segments. A lasso-based model and multivariate cox regression analysis identified a chromosome 17p loss, containing the TP53 tumor suppressor gene, that was significantly associated with reduced survival (P = 0.0139, HR = 1.688, 95% CI = [1.112–2.562]), which was validated by an independent cohort of 187 Stage III CRCs. In summary, this low-coverage WGS protocol has high sensitivity, high resolution and low cost and the identified 17p-loss is an effective poor prognosis marker for Stage III patients.

Landscape of Tumor Suppressor Mutations in Acute Myeloid Leukemia

Acute myeloid leukemia is mainly characterized by a complex and dynamic genomic instability. Next-generation sequencing has significantly improved the ability of diagnostic research to molecularly characterize and stratify patients. This detailed outcome allowed the discovery of new therapeutic targets and predictive biomarkers, which led to develop novel compounds (e.g., IDH 1 and 2 inhibitors), nowadays commonly used for the treatment of adult relapsed or refractory AML. In this review we summarize the most relevant mutations affecting tumor suppressor genes that contribute to the onset and progression of AML pathology. Epigenetic modifications (TET2, IDH1 and IDH2, DNMT3A, ASXL1, WT1, EZH2), DNA repair dysregulation (TP53, NPM1), cell cycle inhibition and deficiency in differentiation (NPM1, CEBPA, TP53 and GATA2) as a consequence of somatic mutations come out as key elements in acute myeloid leukemia and may contribute to relapse and resistance to therapies. Moreover, spliceosomal machinery mutations identified in the last years, even if in a small cohort of acute myeloid leukemia patients, suggested a new opportunity to exploit therapeutically. Targeting these cellular markers will be the main challenge in the near future in an attempt to eradicate leukemia stem cells.