TP53 copy number and protein expression inform mutation status across risk categories in acute myeloid leukemia

p53 immunohistochemistry staining is a rapid screening method for TP53 mutation in myeloid malignancies suitable for integration into routine diagnostic laboratory practice

TP53 mutations are a recognised poor prognostic marker across myeloid malignancies associated with inferior overall survival. Immunohistochemistry (IHC) for p53 represents a promising adjunctive test with rapid turn-around; however, controversy exists around its utility and optimal positive staining threshold. The aims of this study were to determine the diagnostic testing characteristics and optimal threshold of positive staining for p53 IHC in comparison to next-generation sequencing (NGS) results across myeloid malignancies and compare haematopathologist review to digital analysis. A total of 117 bone marrow samples, including TP53 wild-type (n=50) and TP53 mutant (n=67) based on NGS results, were independently assessed by two blinded haematopathologists and analysed using image analysis software with reliability assessment. A receiver operating characteristic curve was used to determine the optimal cut-off for predicting TP53 mutation. There was high reliability between reviewers [intraclass correlation (ICC) 0.84; confidence interval (CI) 0.783-0.891] and between average reviewer and analysis software (ICC 0.794; CI 0.715-0.853). The area under the curve was similar (p=0.818) for computer versus average reviewer. The optimal cut-off for reviewer assessment was 2% strong positive staining with adequate sensitivity (70%) and specificity (90%). p53 IHC has adequate test characteristics to be considered as a rapid screen to identify cases of TP53 mutation. Issues remain in identifying truncating and some splicing mutations.

ARF6 Promotes AML Progression via Activation of PI3K/AKT/mTOR Signaling

BACKGROUND

Acute myeloid leukemia (AML) represents a highly aggressive hematological malignancy characterized by a poor prognosis and a pressing demand for innovative diagnostic and prognostic biomarkers. Recent studies have indicated that ADP-ribosylation factor 6 (ARF6) is overexpressed across various cancer types; however, its specific role and implications in AML have yet to be thoroughly investigated.

METHODS

To elucidate the clinical relevance and functional mechanisms of ARF6 in AML, we conducted an integrated analysis utilizing RNA sequencing data from The Cancer Genome Atlas (TCGA) alongside clinical samples and AML cell lines. The diagnostic potential of ARF6 was assessed through receiver operating characteristic curve analysis, and logistic regression was employed to identify factors correlating with elevated ARF6 expression. Functional assays were performed to elucidate the effects of ARF6 modulation on apoptosis, cell cycle progression, and AML cell proliferation, while mechanistic investigations focused on the PI3K/AKT/mTOR signaling pathway, particularly in the context of pharmacological PI3K inhibition.

RESULTS

Our findings revealed a significant upregulation of ARF6 in AML compared to normal controls, with diagnostic efficacy indicated by an AUC of 0.793. Logistic regression analysis identified older age (> 60 years) and a higher white blood cell count (> 20 × 109/L) as significant predictors of high ARF6 expression. Moreover, elevated ARF6 levels were independently associated with shorter overall survival (HR = 1.634, p = 0.045). Notably, ARF6 knockdown induced apoptosis and G0/G1 cell cycle arrest, whereas its overexpression yielded contrary effects. In addition, ARF6 activated the PI3K/AKT/mTOR pathway, which was abrogated by pharmacological PI3K inhibition.

CONCLUSION

Collectively, our findings establish ARF6 as a valuable diagnostic and prognostic marker in AML, driving disease progression through the activation of the PI3K/AKT/mTOR pathway. These insights not only enhance our understanding of AML pathology but also underscore the potential of targeting ARF6 for therapeutic intervention in AML treatment paradigms. Future research should aim at evaluating the therapeutic implications of targeting ARF6 in combination with existing treatment modalities.

Fifth edition WHO classification: myeloid neoplasms

The fifth edition of the WHO classification of haematolymphoid tumours (WHO-HEM5) introduces significant advancements in the understanding and diagnosis of myeloid neoplasms, emphasising molecular and genetic insights. This review highlights key updates from the revised fourth edition (WHO-HEM4R), particularly the integration of genetic criteria for disease classification. Many entities are now defined by specific genetic abnormalities, enhancing diagnostic precision and prognostic assessment. Notably, the elimination of the 20% blast threshold for acute myeloid leukaemia (AML) with specific defining genetic alterations reflects a shift towards genomic-driven diagnostics. Additional updates include the refined subclassification of myelodysplastic neoplasms (MDS) and MDS/myeloproliferative neoplasms, as well as the recognition of novel entities such as clonal haematopoiesis and MDS with biallelic TP53 inactivation, further expanding the spectrum of myeloid neoplasms. WHO-HEM5 illustrates the diagnostic utility of morphology, flow cytometry, immunohistochemistry and next-generation sequencing in resource-rich settings. However, its implementation in low-income and middle-income countries (LMICs) remains challenging due to limited access to advanced diagnostic tools. This review explores strategies to optimise diagnosis in resource-constrained environments, where morphology and immunophenotyping remain fundamental. By integrating molecular diagnostics with traditional methods, WHO-HEM5 aims to refine classification and facilitate risk stratification in the era of personalised medicine, providing haematopathologists and clinicians with an essential framework to navigate the complexities of myeloid neoplasms. The emphasis on advancing haematopathology practices worldwide, including in LMICs, demonstrates the ongoing commitment to improving global outcomes in haematological malignancies.

Tetrahydrocurcumin-induced apoptosis of hepatocellular carcinoma cells involves the TP53 signaling pathway, as determined by network pharmacology

BACKGROUND

Hepatocellular carcinoma (HCC) is a malignant disease with high incidence and mortality worldwide. This study focuses on the TP53 target protein to investigate the potential therapeutic effect of tetrahydrocurcumin (THC) on HCC and its mechanism of action. The research hypothesis is that THC can inhibit the proliferation, migration, and invasion of HCC cells, and promote their apoptosis by regulating the TP53 target protein.

AIM

To explore the mechanism by which THC inhibits HCC cell proliferation via the TP53 signaling pathway.

METHODS

Potential targets of THC and HCC were identified from multiple databases. The core targets were subjected to analyses using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes databases, and visualization processing, using the online platform Metascape to identify the key molecules and signaling pathways involved in the action of THC against HCC. The molecular mechanisms of action of THC against TP53 in the inhibition of HCC cells were verified using cell counting kit-8, Transwell, apoptosis, and western blotting assays.

RESULTS

Molecular docking results showed that THC had a high score for the TP53 target protein. In vitro experiments indicated that THC effectively inhibited the proliferation and migration of HCC cells, and affected the expression levels of TP53, MDM2, cyclin B, Bax, Bcl-2, caspase-9, and caspase-3.

CONCLUSION

THC induces the apoptosis of HCC cells through the TP53 signaling pathway, thereby inhibiting their proliferation and migration.

TP53 Mutation Status in Myelodysplastic Neoplasm and Acute Myeloid Leukemia: Impact of Reclassification Based on the 5th WHO and International Consensus Classification Criteria: A Korean Multicenter Study

Background

TP53 mutations are associated with poor prognosis in myelodysplastic neoplasm (MDS) and AML. The updated 5th WHO classification and International Consensus Classification (ICC) categorize TP53-mutated MDS and AML as unique entities. We conducted a multicenter study in Korea to investigate the characteristics of TP53-mutated MDS and AML, focusing on diagnostic aspects based on updated classifications.

Methods

This study included patients aged ≥ 18 yrs who were diagnosed as having MDS (N=1,244) or AML (N=2,115) at six institutions. The results of bone marrow examination, cytogenetic studies, and targeted next-generation sequencing, including TP53, were collected and analyzed.

Results

TP53 mutations were detected in 9.3% and 9.2% of patients with MDS and AML, respectively. Missense mutation was the most common, with hotspot codons R248/R273/G245/Y220/R175/C238 accounting for 25.4% of TP53 mutations. Ten percent of patients had multiple TP53 mutations, and 78.4% had a complex karyotype. The median variant allele frequency (VAF) of TP53 mutations was 41.5%, with a notable difference according to the presence of a complex karyotype. According to the 5th WHO classification and ICC, the multi-hit TP53 mutation criteria were met in 58.6% and 75% of MDS patients, respectively, and the primary determinants were a TP53 VAF >50% for the 5th WHO classification and the presence of a complex karyotype for the ICC.

Conclusions

Collectively, we elucidated the molecular genetic characteristics of patients with TP53-mutated MDS and AML, highlighting key factors in applying TP53 mutation-related criteria in updated classifications, which will aid in establishing diagnostic strategies.

Transplantation outcomes of TP53-mutant AML and MDS: a single transplantation center experience of 63 patients

Allogeneic hematopoietic stem cell transplantation is recommended for TP53-mutant acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) despite a high relapse rate and poor survival. To understand TP53 alterations on a molecular level and define stratified prognostic outcomes following transplantation, we performed targeted next-generation sequencing on 63 patients who underwent transplantation for TP53-mutant AML/MDS and profiled their molecular spectrum. Sixty-eight TP53 mutations were detected, with a median variant allele frequency of 46.8%. Copy number alterations at the TP53 locus were present in 19 patients (30%). Complex karyotype was detected in 48 patients (76%) and was significantly associated with larger TP53 clone size, bi-allelic status, and the absence of concurrent mutations, reflecting the high TP53 mutational burden. Specifically, 51 patients (81%) with the dominant TP53 clone greatly overlapped with those with the complex karyotype. Multivariable overall survival (OS) analysis identified AML (hazard ratio [HR], 2.51; P = 0.03) and TP53 clonal dominance (HR, 5.30; P = 0.002) as prognostic factors. One-year OS was worse in AML with the dominant TP53 clone than in others (13% vs 61%; P < 0.001). Our results underscore the utility of mutational profile-guided risk stratification in patients with TP53-mutant AML/MDS, and could aid in transplantation-related decision-making.

Erythroblastic Sarcoma in Adults and Children: Different Pathways to the Same Destination

Erythroblastic sarcoma (ES), the mass-forming presentation of acute erythroid leukemia, is a rare and challenging diagnosis. Given the limited number of published cases, the diagnostic criteria, immunophenotype, and molecular characteristics are not well defined. We describe 56 cases of ES (36 adult and 11 pediatric cases from our cohort, and 9 pediatric cases from the literature). The median age was 60 years among adults and 1.8 years among children. An association with prior cytotoxic therapy or myeloid neoplasm was documented in 10/36 (28%) and 25/36 (69%) adults, respectively, but was not reported in children. Bones were the most common site of involvement among adults (16/36, 44%), whereas soft tissue or central nervous system involvement was most common among children (each 9/20, 45%). Adult and pediatric ES shared similar morphologic features with all cases showing mass formation of erythroblasts and/or involvement of body fluids. Immunophenotypic analysis showed that blasts were positive for CD71 (49/49, 100%), GLUT1 (12/12, 100%), CD43 (37/39, 95%), E-cadherin (38/44, 86%), and CD117 (39/51, 76%) but were mostly negative for CD45 (15/48, 31% positive). Strong and diffuse P53 expression was common among adults (21/24, 88%) and absent among children (3/10, 30% with dim/subset positivity). Although a complex karyotype was common in adult (15/17, 88%) and pediatric ES (8/12, 68%), TP53 mutations were exclusively seen in adult ES (17/19, 89%), at least 11 of which (65%) were biallelic. Instead, pediatric ES was enriched for gene fusions; specific fusions were identified in 10 cases, 7 of which involved NFIA rearrangement. The prognosis was poor among both age groups; 29/37 (78%) patients died from disease with a median overall survival of 3 months. Overall, these results show that adult and pediatric ES have overlapping morphologic and immunophenotypic features but distinct molecular profiles suggesting diverging pathogenesis.

Diagnosis of TP53-mutated myeloid disease by the ICC and WHO fifth edition classifications

ABSTRACT

The International Consensus (ICC) and World Health Organization fifth edition (WHO5) classifications introduced new, but differing, categories of myeloid disease defined by TP53 mutations. We reviewed a cohort of 188 cases of TP53-mutated myeloid disease to determine how diagnoses and outcomes differ between the 2 classifications. Overall, 120 (64%) cases were classified differently by the ICC and WHO5, including 24 of 80 (30%) cases with <20% blasts. These cases were discrepantly categorized primarily because of inclusion of complex karyotype (CK) as a surrogate for biallelic TP53 inactivation only in the ICC. However, there were no significant differences in clinicopathologic characteristics or overall survival between cases categorized as TP53-mutated disease by both classifications and those with a single TP53 mutation and CK, suggesting that CK reliably identifies TP53-mutated cases with biallelic TP53 inactivation. Most cases of acute myeloid leukemia (AML; 96/102 [94%]) were discrepantly diagnosed between the ICC and WHO5 because of the introduction of AML with mutated TP53 as a distinct category only in the ICC. Nearly all of these were instead diagnosed as AML, myelodysplasia related (AML-MR) by WHO5. However, when compared with a separate cohort of patients with AML-MR without TP53 mutations, patients with TP53-mutated AML showed a distinct genetic profile and significantly worse overall survival, supporting the inclusion of AML with mutated TP53 as a distinct disease category. Overall, our results show that a significant percentage of TP53-mutated myeloid disease is classified differently by the ICC and WHO5 and highlight areas to address in future classification systems.

MDM2 inhibition is associated with the emergence of TP53-altered clonal hematopoiesis

Murine double minute 2 (MDM2) inhibitors have shown promising activity in TP53-wild type tumors and are under active investigation across a spectrum of malignancies. Herein, we report a 51-year-old female with MDM2-amplified, TP53-wild type adenoid cystic carcinoma who was treated with a MDM2 inhibitor and developed persistent pancytopenia despite drug discontinuation. Her pancytopenia was associated with 20 distinct pathogenic TP53 mutations in peripheral blood and bone marrow not present in drug-resistant tumor tissue. Plasma TP53 mutations were similarly detected among 4 other patients treated at our institution, with the number of mutations correlating strongly with duration of treatment. This case suggests that MDM2 inhibitors are associated with TP53 clonal hematopoiesis, which may confer a risk of subsequent myeloid malignancy. As multiple MDM2 inhibitor trials are ongoing, our findings underscore the need for further investigation into the potential long-term deleterious effects of these inhibitors in the hematopoietic stem and progenitor compartment.

Are TP53 mutations all alike?

TP53 is mutated in 10 to 15% of cases of acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) and is associated with a previous exposure to cytotoxic therapy, complex cytogenetic abnormalities, and a poor prognosis. Recent data have established the importance of TP53-mutant allele status, the determination of which requires specific genetic testing. Compared with monoallelic disease, multihit TP53-mutant AML/MDS is associated with chromosomal abnormalities and decreased overall survival. Most TP53 mutations are missense mutations that localize to the DNA binding domain. Hot-spot mutations involving residues R175, Y220, G245, R248, R273, or R282 represent approximately 35% of all TP53 missense mutations in AML/MDS. There is evidence that these hot-spot mutations may have dominant negative or gain-of-function properties. Here we review this evidence and discuss its potential impact on patient outcomes and clinical management.

Contemporary Approach to the Diagnosis and Classification of Myelodysplastic Neoplasms/Syndromes-Recommendations From the International Consortium for Myelodysplastic Neoplasms/Syndromes (MDS [icMDS])

Myelodysplastic neoplasms/syndromes (MDS) are a heterogeneous group of biologically distinct entities characterized by variable degrees of ineffective hematopoiesis. Recently, 2 classification systems (the 5th edition of the World Health Organization Classification of Haematolymphoid tTumours and the International Consensus Classification) further subcharacterized MDS into morphologically and genetically defined groups. Accurate diagnosis and subclassification of MDS require a multistep systemic approach. The International Consortium for MDS (icMDS) summarizes a contemporary, practical, and multimodal approach to MDS diagnosis and classification.

The prognostic effect of blast count in TP53 mutant myeloid neoplasms -the Minnesota experience

In 2022, the World Health Organization (WHO) and International Consensus Classification (ICC) recognized TP53 as an entity-defining alteration in myeloid neoplasms, yet with differing criteria that could lead to discrepant diagnoses and affect clinical trial eligibility. We studied 67 patients with TP53 mutant myeloid neoplasms, reclassifying them using both criteria. While most cases fulfill the criteria for TP53 mutant defined entities, most discrepancies were found in cases with ≥20% blasts. Patients were stratified into three groups based on blast count (<10%, 10-19%, and ≥20%) which revealed comparable clinicopathologic features, genetic characteristics, and outcomes. Notably, patients with ≥10% blasts had shorter overall survival compared to those with <10% blasts (8.1 vs. 12.4 months; p = 0.03). This study is among the few to examine TP53 mutant myeloid neoplasms as a single entity and suggests that the 10% blast count threshold could serve as a gateway to a more harmonized classification for these patients.

Overall survival in TP53-mutated AML and MDS

TP53 mutations in patients with AML and MDS frequently portend a poor prognosis, related to both p53 allele status and blast count. In 2022, the ICC and WHO released updated guidelines for classifying p53-mutated AML/MDS. The characteristics of p53 mutations, their associated co-mutations, and their effects on overall survival (OS) are not known in the context of these new guidelines. A retrospective chart review was undertaken for all patients with AML or MDS and at least one TP53 mutation detected on next generation sequencing (NGS) at Yale New Haven Hospital from 2015 to 2023. All patients (N = 210) met criteria for one of the 5 diagnostic classes based on WHO and ICC guidelines. Kaplan-Meier curves with associated log-rank testing and Cox proportional hazards model quantified the effects of clinical and molecular data on survival. Multi-hit pathogenic mutations were related to poorer OS in MDS but not AML using either the WHO (p = .02) or the ICC (p = .01) diagnostic criteria. The most significant predictors of OS in the sample overall were platelet count < 50 K (HR: 2.01, 95% CI [1.47, 2.75], p < .001) and TP53 VAF ≤ 40% (HR: 0.68, 95% CI[0.50, 0.91], p = .01). Blast count ranges, complex karyotype, and p53 mutation type or location, showed no association with OS. In our cohort defined by the 2022 ICC and WHO criteria, VAF and thrombocytopenia, rather than blast count or p53 mutation features, significantly predicted OS. These results speak to each criteria's ability to identify cases of similarly aggressive disease biology and prognosis.

Single-cell multi-omics reveal stage of differentiation and trajectory-dependent immunity-related gene expression patterns in human erythroid cells

The role of Erythroid cells in immune regulation and immunosuppression is one of the emerging topics in modern immunology that still requires further clarification as Erythroid cells from different tissues and different species express different immunoregulatory molecules. In this study, we performed a thorough investigation of human bone marrow Erythroid cells from adult healthy donors and adult acute lymphoblastic leukemia patients using the state-of-the-art single-cell targeted proteomics and transcriptomics via BD Rhapsody and cancer-related gene copy number variation analysis via NanoString Sprint Profiler. We found that human bone marrow Erythroid cells express the ARG1, LGALS1, LGALS3, LGALS9, and C10orf54 (VISTA) immunosuppressive genes, CXCL5, CXCL8, and VEGFA cytokine genes, as well as the genes involved in antimicrobial immunity and MHC Class II antigen presentation. We also found that ARG1 gene expression was restricted to the single erythroid cell cluster that we termed ARG1-positive Orthochromatic erythroblasts and that late Erythroid cells lose S100A9 and gain MZB1 gene expression in case of acute lymphoblastic leukemia. These findings show that steady-state erythropoiesis bone marrow Erythroid cells express myeloid signature genes even without any transdifferentiating stimulus like cancer.

Patients with TP53-Mutated Acute Myeloid Leukemia Receiving Intensive Induction Therapy Have Superior Outcomes Due to a Higher Rate of Salvage Therapy: A Single Institution, Retrospective Study

BACKGROUND

TP53 mutations (TP53m) define the most treatment-refractory acute myeloid leukemia (AML) subtype. Optimal treatment approaches have not been established in this setting. We reviewed our institutional experience to identify therapy sequencing, treatment response, and survival patterns in these patients.

METHODS

This study was a single-center, retrospective cohort analysis.

RESULTS

Our cohort includes 86 TP53m and 337 TP53 wild-type (TP53wt) adult AML patients. TP53m AML patients presented with lower bone marrow and peripheral blasts; none presented with hyperleukocytosis. Patients who received intensive treatment up front demonstrated superior overall survival (OS) over those receiving first-line non-intensive therapy (2-year OS 22% versus 7%; p = 0.02). However, the complete remission (CR) rates among the first-line intensive and non-intensive therapy groups were comparable (21.9% and 29.4%, respectively, p = 0.49). The improved OS is therefore attributed to superior cumulative CR in the intensive group. First-line intensively treated patients were more likely to receive and respond to salvage, leading to a cumulative CR rate of 65.7% (versus 29.4%, p = 0.003). Achieving CR at any point is strongly associated with superior survival outcomes with 2-year OS of 31% versus 0% for those not achieving CR ever (p < 0.01).

CONCLUSIONS

We find that TP53m AML rarely presents with oncological emergencies, suggesting that clinical trial enrollment is feasible in this group. Additionally, in our cohort, intensive induction therapies lead to superior survival outcomes attributed to successful salvage therapy. These data suggest that strategic therapy sequencing and salvage therapy may be important in optimizing outcomes for TP53m AML patients.

Impact of p53-associated acute myeloid leukemia hallmarks on metabolism and the immune environment

Acute myeloid leukemia (AML), an aggressive malignancy of hematopoietic stem cells, is characterized by the blockade of cell differentiation, uncontrolled proliferation, and cell expansion that impairs healthy hematopoiesis and results in pancytopenia and susceptibility to infections. Several genetic and chromosomal aberrations play a role in AML and influence patient outcomes. TP53 is a key tumor suppressor gene involved in a variety of cell features, such as cell-cycle regulation, genome stability, proliferation, differentiation, stem-cell homeostasis, apoptosis, metabolism, senescence, and the repair of DNA damage in response to cellular stress. In AML, TP53 alterations occur in 5%-12% of de novo AML cases. These mutations form an important molecular subgroup, and patients with these mutations have the worst prognosis and shortest overall survival among patients with AML, even when treated with aggressive chemotherapy and allogeneic stem cell transplant. The frequency of TP53-mutations increases in relapsed and recurrent AML and is associated with chemoresistance. Progress in AML genetics and biology has brought the novel therapies, however, the clinical benefit of these agents for patients whose disease is driven by TP53 mutations remains largely unexplored. This review focuses on the molecular characteristics of TP53-mutated disease; the impact of TP53 on selected hallmarks of leukemia, particularly metabolic rewiring and immune evasion, the clinical importance of TP53 mutations; and the current progress in the development of preclinical and clinical therapeutic strategies to treat TP53-mutated disease.

p53 as a Potential Actionable Target in Myxofibrosarcoma: A Molecular and Pathologic Review of a Single-Institute Series

Myxofibrosarcoma (MFS) is a common adult soft tissue sarcoma characterized by high-local recurrence rate, poorly understood molecular pathogenesis, lack of specific prognostic markers, and effective targeted therapies. To gain further insights into the disease, we analyzed a well-defined group of 133 primary MFS cases. Immunohistochemical (IHC) staining for p53, MET, RET, and RB was performed. Twenty-five cases were analyzed by targeted resequencing of known cancer driver hotspot mutations, whereas 66 and 64 MFSs were examined for the presence of genetic variants in TP53 and MET gene, respectively. All clinical, histologic, immunostaining, and genetic variables were analyzed for their impact on 5-years overall survival (OS) and 5-years event-free survival (EFS). In our series, no grade I tumors relapsed and high grade are related to a positive MET immunostaining (P = .034). Both local recurrence (P = .038) and distal metastases (P = .016) correlated to the presence of "single nucleotide variant (SNV) plus copy number variation (CNV)" in TP53. Multivariate analysis revealed that age (>60 years), metastasis at presentation, and positive IHC-p53 signal are risk factors for a poor OS (P = .003, P = .000, and P = .002), whereas age (>60 years), synchronous metastasis, and tumor size (>10 cm) predict an unfavorable 5-years EFS (P = .011, P = .000, and P = .023). Considering the smaller series (n = 66) that underwent molecular screening, the presence of "SNV+CNV" in TP53 represents a risk factor for a worse 5-years EFS (hazard ratio, 2.5; P = .017). The present series confirms that TP53 is frequently altered in MFS (86.4% of cases), appearing to play an important role in MFS tumorigenesis and being a potentially drugable target. A positive p53 immunostainings is related to a poor diagnosis, and it is the presence of a single nucleotide genetic alterations in TP53 that is essential in conferring MFS an aggressive phenotype, thus supporting the use of molecular profiling in MFS to better define the role of p53 as a prognostic factor.

Exploring p53 protein expression and its link to TP53 mutation in myelodysplasia-related malignancies-Interpretive challenges and potential field of applications

AIMS

TP53 alterations have a significant prognostic effect in myeloid neoplasms. Our objective was to investigate the TP53 gene mutation status, p53 protein expression and their relationship in dysplasia-related myeloid neoplasms with varying levels of myeloblast counts.

METHODS AND RESULTS

A total of 76 bone marrow biopsy samples with different blast counts were analysed. Total and strong (3+) p53 expression was determined. Dual immunohistochemical staining was performed to determine the cell population associated with p53 expression. NGS analysis was performed using the Accel-Amplicon Comprehensive TP53 panel. Both p53 expression and TP53 VAF showed a significant correlation with the myeloblast ratio (P < 0.0001); however, p53 expression was also present in other cell lineages. The VAF value exhibited a significant correlation with p53 expression. A high specificity (0.9800) was observed for TP53 mutation using the ≥ 10% strong (3+) p53 cut-off value, although the sensitivity (0.4231) was low.

CONCLUSIONS

Strong (3+) p53 expression using a ≥ 10% cut-off value accurately predicts TP53 mutation but does not reveal the allelic state. The p53 expression is significantly influenced by myeloblast count, and histological interpretation should consider the presence of intermixed non-neoplastic marrow cells with varying physiological p53 expression.

Real world predictors of response and 24-month survival in high-grade TP53-mutated myeloid neoplasms

Current therapies for high-grade TP53-mutated myeloid neoplasms (≥10% blasts) do not offer a meaningful survival benefit except allogeneic stem cell transplantation in the minority who achieve a complete response to first line therapy (CR1). To identify reliable pre-therapy predictors of complete response to first-line therapy (CR1) and outcomes, we assembled a cohort of 242 individuals with TP53-mutated myeloid neoplasms and ≥10% blasts with well-annotated clinical, molecular and pathology data. Key outcomes examined were CR1 & 24-month survival (OS24). In this elderly cohort (median age 68.2 years) with 74.0% receiving frontline non-intensive regimens (hypomethylating agents +/- venetoclax), the overall cohort CR1 rate was 25.6% (50/195). We additionally identified several pre-therapy factors predictive of inferior CR1 including male gender (P = 0.026), ≥2 autosomal monosomies (P < 0.001), -17/17p (P = 0.011), multi-hit TP53 allelic state (P < 0.001) and CUX1 co-alterations (P = 0.010). In univariable analysis of the entire cohort, inferior OS24 was predicated by ≥2 monosomies (P = 0.004), TP53 VAF > 25% (P = 0.002), TP53 splice junction mutations (P = 0.007) and antecedent treated myeloid neoplasm (P = 0.001). In addition, mutations/deletions in CUX1, U2AF1, EZH2, TET2, CBL, or KRAS ('EPI6' signature) predicted inferior OS24 (HR = 2.0 [1.5-2.8]; P < 0.0001). In a subgroup analysis of HMA +/-Ven treated individuals (N = 144), TP53 VAF and monosomies did not impact OS24. A risk score for HMA +/-Ven treated individuals incorporating three pre-therapy predictors including TP53 splice junction mutations, EPI6 and antecedent treated myeloid neoplasm stratified 3 prognostic distinct groups: intermediate, intermediate-poor, and poor with significantly different median (12.8, 6.0, 4.3 months) and 24-month (20.9%, 5.7%, 0.5%) survival (P < 0.0001). For the first time, in a seemingly monolithic high-risk cohort, our data identifies several baseline factors that predict response and 24-month survival.

TP53 Mutations in Acute Leukemias and Myelodysplastic Syndromes: Insights and Treatment Updates

TP53 mutations are found in 5%-10% of de novo myelodysplastic syndrome (MDS) and AML cases. By contrast, in therapy related MDS and AML, mutations in TP53 are found in up to 30%-40% of patients. The majority of inactivating mutations observed in MDS and AML are missense mutations localized in a few prevalent hotspots. TP53 missense mutations together with truncating mutations or chromosomal loss of TP53 determine a loss-of-function effect on normal p53 function. Clonal expansion of TP53-mutant clones is observed under the selection pressure of chemotherapy or MDM2 inhibitor therapy. TP53-mutant clones are resistant to current chemotherapy, and when responses to treatment have been observed, they have correlated poorly with overall survival. The most heavily investigated and targeted agent for patients with TP53-mutant MDS and AML has been APR-246 (eprenetapopt) a p53 reactivator, in combination with azacitidine, but also in triplets with venetoclax. Despite positive results in phase II trials, a phase III trial did not confirm superior response or improved survival. Other agents, like magrolimab (anti-CD47 antibody), failed to demonstrate improved activity in TP53-mutant MDS and AML. Agents whose activity is not dependent on a functional apoptosis system like anti-CD123 antibodies or cellular therapies are in development and may hold promises. Delivering prognostic information in a dismal disease like TP53-mutated MDS and AML is particularly challenging. The physician should balance hope and realism, describing the trajectory of possible treatments and at the same time indicating the poor outcome, together with promoting adaptive coping in patients and elaborating on the nature of the disease.

TP53 in MDS and AML: Biological and clinical advances

Recently, the WHO-5 and the ICC 2022 criteria have emphasized poor prognosis in AML/MDS patients with multi-hit TP53 mutations, whereas mutated TP53 plays a critical role in tumorigenesis, drawing substantial interest in exploring its biological behaviors. Diverse characteristics of TP53 mutations, including types, VAF, CNVs, allelic status, karyotypes, and concurrent mutations have been extensively studied. Novel potential targets and comprehensive treatment strategies nowadays are under swift development, owing to great advances in technology. However, accurately predicting prognosis of patients with TP53-mutated myeloid neoplasms remains challenging. And there is still a lack of effective treatment for those patients.

Immunohistochemistry screening for TP53 mutation in myeloid neoplasms in AZF-fixed bone marrow biopsies

TP53 mutational status in myeloid neoplasms is prognostic and in acute myeloid leukaemia (AML) may lead to alternative induction therapy; therefore, rapid assessment is necessary for precision treatment. Assessment of multiple prognostic genes by next generation sequencing in AML is standard of care, but the turn-around time often cannot support rapid clinical decision making. Studies in haematological neoplasms suggest p53 immunohistochemistry (IHC) correlates with TP53 mutational status, but they have used variable criteria to define TP53 overexpression. p53 IHC was performed and interpreted on AZF-fixed, acid decalcified bone marrow biopsies on 47 cases of clonal myeloid neoplasms with TP53 mutations between 2016 and 2019 and 16 control samples. Results were scored by manual and digital analysis. Most TP53-mutated cases (81%) overexpressed p53 by digital analysis and manual analysis gave similar results. Among the nine TP53-mutated IHC-negative cases, seven (78%) were truncating mutations and two (22%) were single-hit missense mutations. Using a digital cut-off of at least 3% ≥1+ positive nuclei, the sensitivity and specificity are 81% and 100%; cases with loss-of-function mutations were more likely to be negative. In this cohort, p53 immunopositivity correlated with TP53 mutational status, especially missense mutations, with excellent specificity. Truncating TP53 mutations explain most IHC-negative cases, impacting the sensitivity. We demonstrate that p53 IHC can screen for TP53 mutations allowing quicker treatment decisions for most patients. However, not all patients will be identified, so molecular studies are required. Furthermore, cut-offs for positivity vary in the literature, consequently laboratories should independently validate their processes before adopting p53 IHC for clinical use. p53 IHC performs well to screen for TP53 mutations in AZF-fixed bone marrow. Performance in our setting differs from the literature, which shows variability of pre-analytic factors and cut-offs used to screen for TP53 mutations. Each laboratory should validate p53 IHC to screen for TP53 mutations in their unique setting.

p53 biology and reactivation for improved therapy in MDS and AML

Myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) originate from preleukemic hematopoietic conditions, such as clonal hematopoiesis of indeterminate potential (CHIP) or clonal cytopenia of undetermined significance (CCUS) and have variable outcomes despite the successful implementation of targeted therapies. The prognosis differs depending on the molecular subgroup. In patients with TP53 mutations, the most inferior outcomes across independent studies were observed. Myeloid malignancies with TP53 mutations have complex cytogenetics and extensive structural variants. These factors contribute to worse responses to induction therapy, demethylating agents, or venetoclax-based treatments. Survival of patients with biallelic TP53 gene mutations is often less than one year but this depends on the type of treatment applied. It is still controversial whether the allelic state of mutant TP53 impacts the outcomes in patients with AML and high-risk MDS. Further studies are needed to justify estimating TP53 LOH status for better risk assessment. Yet, TP53-mutated MDS, MDS/AML and AML are now classified separately in the International Consensus Classification (ICC). In the clinical setting, the wild-type p53 protein is reactivated pharmacologically by targeting p53/MDM2/MDM4 interactions and mutant p53 reactivation is achieved by refolding the DNA binding domain to wild-type-like conformation or via targeted degradation of the mutated protein. This review discusses our current understanding of p53 biology in MDS and AML and the promises and failures of wild-type and mutant p53 reactivation in the clinical trial setting.

A cuproptosis-related gene expression signature predicting clinical prognosis and immune responses in intrahepatic cholangiocarcinoma detected by single-cell RNA sequence analysis

BACKGROUND

Cholangiocarcinoma represents a malignant neoplasm originating from the hepatobiliary tree, with a subset of tumors developing inside the liver. Intrahepatic cholangiocarcinomas (ICC) commonly exhibit an asymptomatic presentation, rendering both diagnosis and treatment challenging. Cuproptosis, an emerging regulated cell death pathway induced by copper ions, has garnered attention recently. As cancer cells show altered copper metabolism and comparatively higher copper needs, cuproptosis may play a role in the development of ICC. However, studies investigating this possibility are currently lacking.

METHODS

Single-cell and bulk RNA sequence data were analyzed, and correlations were established between the expression of cuproptosis-related molecules and ICC patient survival. Genes with predicting survival were used to create a CUPT score using Cox and LASSO regression and tumor mutation burden (TMB) analysis. The CIBERSORT software was employed to characterize immune cell infiltration within the tumors. Furthermore, immune infiltration prediction, biological function enrichment, and drug sensitivity analyses were conducted to explore the potential implications of the cuproptosis-related signature. The effects of silencing solute carrier family 39 member 4 gene (SLC39A4) expression using siRNA were investigated using assays measuring cell proliferation, colony formation, and cell migration. Key genes of cuproptosis were detected by western blotting.

RESULTS

The developed CUPT score divided patients into high and low CUPT score groups. Those with a low score had significantly better prognosis and longer survival. In contrast, high CUPT scores were associated with worse clinical outcomes and significantly higher TMB. Comparisons of the two groups also indicated differences in the immune infiltrate present in the tumors. Finally, we were able to identify 95 drugs potentially affecting the cuproptosis pathway. Some of these might be effective in the treatment of ICC. The in vitro experiments revealed that suppressing the expression of SLC39A4 in ICC cell lines resulted in reduced cell proliferation, colony formation, and cell migration. It also led to an increase in cell death and the upregulation of key genes associated with cuproptosis, namely ferredoxin 1 (FDX1) and dihydrolipoyl transacetylase (DLAT). These findings strongly suggest that this cuproptosis-associated molecule may play a pivotal role in the development and metastasis of ICC.

CONCLUSIONS

Changes in the expression of a cuproptosis-related gene signature can predict the clinical prognosis of ICC with considerable accuracy. This supports the notion that cuproptosis influences the diversity and complexity of the immune microenvironment, mutational landscape, and biological behavior of ICC. Understanding this pathway better may hold promise for the development of innovative strategies in the management of this disease.

Pathophysiology of Acute Myeloid Leukemia

BACKGROUND

Acute myeloid leukemia (AML) is a biologically heterogenous disease arising in clonally proliferating hematopoietic stem cells. Sequential acquisition of mutations leads to expanded proliferation of clonal myeloid progenitors and failure of differentiation, leading to fulminant AML.

SUMMARY

Here, we review the pathophysiology of AML with a focus on factors predisposing to AML development, including prior chemo- and radiation therapy, environmental factors, and germline predisposition.

KEY MESSAGE

Increasing genomic characterization of AML and insight into mechanisms of its development will be critical to improvement in AML prognostication and therapy.

Utility or futility? A contemporary approach to allogeneic hematopoietic cell transplantation for TP53-mutated MDS/AML

ABSTRACT

TP 53-mutated myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) are among the most lethal malignancies, characterized by dismal outcomes with currently available therapies. Allogeneic hematopoietic cell transplantation (allo-HCT) is widely thought to be the only treatment option to offer durable disease control. However, outcomes with allo-HCT in this context are quite poor, calling into question the utility of transplantation. In this review, we summarize the latest data on allo-HCT outcomes in this subgroup, evaluating the limitations of available evidence; we review the molecular heterogeneity of this disease, delineating outcomes based on distinct biological features to aid in patient selection; and we critically examine whether allo-HCT should be routinely applied in this disease on the basis of currently available data. We propose that the exceptionally poor outcomes of patients with TP53-mutated MDS/AML with biallelic loss and/or adverse-risk cytogenetics should motivate randomized-controlled trials of HCT vs non-HCT to determine whether transplantation can prolong survival and/or positively impact other clinically relevant outcomes such as patient-reported outcomes or healthcare resource utilization in this disease subset. Without dedicated prospective randomized trials, selecting who may actually derive benefit from allo-HCT for TP53-mutated MDS/AML can be described as ambiguous guesswork and must be carefully contemplated.

Pharmacological reactivation of p53 in the era of precision anticancer medicine

p53, which is encoded by the most frequently mutated gene in cancer, TP53, is an attractive target for novel cancer therapies. Despite major challenges associated with this approach, several compounds that either augment the activity of wild-type p53 or restore all, or some, of the wild-type functions to p53 mutants are currently being explored. In wild-type TP53 cancer cells, p53 function is often abrogated by overexpression of the negative regulator MDM2, and agents that disrupt p53-MDM2 binding can trigger a robust p53 response, albeit potentially with induction of p53 activity in non-malignant cells. In TP53-mutant cancer cells, compounds that promote the refolding of missense mutant p53 or the translational readthrough of nonsense mutant TP53 might elicit potent cell death. Some of these compounds have been, or are being, tested in clinical trials involving patients with various types of cancer. Nonetheless, no p53-targeting drug has so far been approved for clinical use. Advances in our understanding of p53 biology provide some clues as to the underlying reasons for the variable clinical activity of p53-restoring therapies seen thus far. In this Review, we discuss the intricate interactions between p53 and its cellular and microenvironmental contexts and factors that can influence p53's activity. We also propose several strategies for improving the clinical efficacy of these agents through the complex perspective of p53 functionality.

Fifth Edition of the World Health Classification of Tumors of the Hematopoietic and Lymphoid Tissue: Myeloid Neoplasms

In this manuscript, we review myeloid neoplasms in the fifth edition of the World Health Organization classification of hematolymphoid tumors (WHO-HEM5), focusing on changes from the revised fourth edition (WHO-HEM4R). Disease types and subtypes have expanded compared with WHO-HEM4R, mainly because of the expansion in genomic knowledge of these diseases. The revised classification is based on a multidisciplinary approach including input from a large body of pathologists, clinicians, and geneticists. The revised classification follows a hierarchical structure allowing usage of family (class)-level definitions where the defining diagnostic criteria are partially met or a complete investigational workup has not been possible. Overall, the WHO-HEM5 revisions to the classification of myeloid neoplasms include major updates and revisions with increased emphasis on genetic and molecular drivers of disease. The most notable changes have been applied to the sections of acute myeloid leukemia and myelodysplastic neoplasms (previously referred to as myelodysplastic syndrome) with incorporation of novel, disease-defining genetic changes. In this review we focus on highlighting the updates in the classification of myeloid neoplasms, providing a comparison with WHO-HEM4R, and offering guidance on how the new classification can be applied to the diagnosis of myeloid neoplasms in routine practice.

DNA Sequencing of CD138 Cell Population Reveals TP53 and RAS-MAPK Mutations in Multiple Myeloma at Diagnosis

Multiple myeloma is a hematologic neoplasm caused by abnormal proliferation of plasma cells. Sequencing studies suggest that plasma cell disorders are caused by both cytogenetic abnormalities and oncogene mutations. Therefore, it is necessary to detect molecular abnormalities to improve the diagnosis and management of MM. The main purpose of this study is to determine whether NGS, in addition to cytogenetics, can influence risk stratification and management. Additionally, we aim to establish whether mutational analysis of the CD138 cell population is a suitable option for the characterization of MM compared to the bulk population. Following the separation of the plasma cells harvested from 35 patients newly diagnosed with MM, we performed a FISH analysis to detect the most common chromosomal abnormalities. Consecutively, we used NGS to evaluate NRAS, KRAS, BRAF, and TP53 mutations in plasma cell populations and in bone marrow samples. NGS data showed that sequencing CD138 cells provides a more sensitive approach. We identified several variants in BRAF, KRAS, and TP53 that were not previously associated with MM. Considering that the presence of somatic mutations could influence risk stratification and therapeutic approaches of patients with MM, sensitive detection of these mutations at diagnosis is essential for optimal management of MM.

Recent advances in precision medicine for acute myeloid leukemia

PURPOSE OF REVIEW

Acute myeloid leukemia (AML) is a heterogeneous disease, in which treatment response and patient survival are highly conditioned by the leukemia biology. The aim of this review is to summarize recent advances in AML classification, risk stratification models, measurable residual disease (MRD) and the increasing number of treatment options that are paving the way towards precision medicine in AML.

RECENT FINDINGS

AML classification and risk stratification were recently updated by incorporating novel molecular markers that are important for diagnosis and outcome prediction. In addition, the impact of co-mutational patterns is under investigation and novel approaches using machine learning algorithms are starting to be used for individualized risk estimation. Molecular markers are also becoming useful in predicting response to non-intensive treatments. MRD informs of treatment response with high sensitivity, allowing dynamic patient risk assessment and early intervention. Finally, important advances were made in AML therapy, with an increasing number of targeted therapies becoming available and many novel treatment approaches being under development with promising early results.

SUMMARY

A better understanding of AML biology is leading to improved risk stratification and important advances in treatments, which are allowing the development of precision medicine in AML at an unprecedented pace.

Current State and Future Prospects of Diagnosis and Management of TP53-Mutated Myeloid Neoplasms

TP53-mutated myeloid neoplasms including acute myeloid leukemia (AML) and myelodysplastic neoplasms (MDS) are notoriously treatment resistant with uniformly poor outcomes. TP53 status is an important prognostic indicator and early knowledge of the TP53 mutation/allelic state may assist in appropriate management including clinical trial enrollment for eligible patients. Thus far, no therapy has shown to demonstrate durable response or incremental survival benefit in TP53-mutated AML or MDS. Therefore, there is an urgent need for innovative therapies to improve the outcomes in this notoriously recalcitrant genomic subset. In this review, we dissect the biology, classification, prognosis, current treatment landscape, and the early phase evaluation of investigational agents in TP53-mutated AML and MDS.

Acute myeloid leukemia: from NGS, through scRNA-seq, to CAR-T. dissect cancer heterogeneity and tailor the treatment

Acute myeloid leukemia (AML) is a malignant blood cancer with marked cellular heterogeneity due to altered maturation and differentiation of myeloid blasts, the possible causes of which are transcriptional or epigenetic alterations, impaired apoptosis, and excessive cell proliferation. This neoplasm has a high rate of resistance to anticancer therapies and thus a high risk of relapse and mortality because of both the biological diversity of the patient and intratumoral heterogeneity due to the acquisition of new somatic changes. For more than 40 years, the old gold standard "one size fits all" treatment approach included intensive chemotherapy treatment with anthracyclines and cytarabine.The manuscript first traces the evolution of the understanding of the pathology from the 1970s to the present. The enormous strides made in its categorization prove to be crucial for risk stratification, enabling an increasingly personalized diagnosis and treatment approach.Subsequently, we highlight how, over the past 15 years, technological advances enabling single cell RNA sequencing and T-cell modification based on the genomic tools are affecting the classification and treatment of AML. At the dawn of the new millennium, the advent of high-throughput next-generation sequencing technologies has enabled the profiling of patients evidencing different facets of the same disease, stratifying risk, and identifying new possible therapeutic targets that have subsequently been validated. Currently, the possibility of investigating tumor heterogeneity at the single cell level, profiling the tumor at the time of diagnosis or after treatments exist. This would allow the identification of underrepresented cellular subclones or clones resistant to therapeutic approaches and thus responsible for post-treatment relapse that would otherwise be difficult to detect with bulk investigations on the tumor biopsy. Single-cell investigation will then allow even greater personalization of therapy to the genetic and transcriptional profile of the tumor, saving valuable time and dangerous side effects. The era of personalized medicine will take a huge step forward through the disclosure of each individual piece of the complex puzzle that is cancer pathology, to implement a "tailored" therapeutic approach based also on engineered CAR-T cells.

TP53 Mutation in Acute Myeloid Leukemia: An Old Foe Revisited

INTRODUCTION

TP53 is the most commonly mutated gene in human cancers and was the first tumor suppressor gene to be discovered in the history of medical science. Mutations in the TP53 gene occur at various genetic locations and exhibit significant heterogeneity among patients. Mutations occurring primarily within the DNA-binding domain of TP53 result in the loss of the p53 protein's DNA-binding capability. However, a complex phenotypic landscape often combines gain-of-function, dominant negative, or altered specificity features. This complexity poses a significant challenge in developing an effective treatment strategy, which eradicates TP53-mutated cancer clones. This review summarizes the current understanding of TP53 mutations in AML and their implications. TP53 mutation in AML: In patients with acute myeloid leukemia (AML), six hotspot mutations (R175H, G245S, R248Q/W, R249S, R273H/S, and R282W) within the DNA-binding domain are common. TP53 mutations are frequently associated with a complex karyotype and subgroups of therapy-related or secondary AML. The presence of TP53 mutation is considered as a poor prognostic factor. TP53-mutated AML is even classified as a distinct subgroup of AML by itself, as TP53-mutated AML exhibits a significantly distinct landscape in terms of co-mutation and gene expression profiles compared with wildtype (WT)-TP53 AML.

CLINICAL IMPLICATIONS

To better predict the prognosis in cancer patients with different TP53 mutations, several predictive scoring systems have been proposed based on screening experiments, to assess the aggressiveness of TP53-mutated cancer cells. Among those scoring systems, a relative fitness score (RFS) could be applied to AML patients with TP53 mutations in terms of overall survival (OS) and event-free survival (EFS). The current standard treatment, which includes cytotoxic chemotherapy and allogeneic hematopoietic stem cell transplantation, is largely ineffective for patients with TP53-mutated AML. Consequently, most patients with TP53-mutated AML succumb to leukemia within several months, despite active anticancer treatment. Decitabine, a hypomethylating agent, is known to be relatively effective in patients with AML. Numerous trials are ongoing to investigate the effects of novel drugs combined with hypomethylating agents, TP53-targeting agents or immunologic agents.

CONCLUSIONS

Developing an effective treatment strategy for TP53-mutated AML through innovative and multidisciplinary research is an urgent task. Directly targeting mutated TP53 holds promise as an approach to combating TP53-mutated AML, and recent developments in immunologic agents for AML offer hope in this field.

Interaction between myelodysplasia-related gene mutations and ontogeny in acute myeloid leukemia

Accurate classification and risk stratification are critical for clinical decision making in patients with acute myeloid leukemia (AML). In the newly proposed World Health Organization and International Consensus classifications of hematolymphoid neoplasms, the presence of myelodysplasia-related (MR) gene mutations is included as 1 of the diagnostic criteria for AML, AML-MR, based largely on the assumption that these mutations are specific for AML with an antecedent myelodysplastic syndrome. ICC also prioritizes MR gene mutations over ontogeny (as defined in the clinical history). Furthermore, European LeukemiaNet (ELN) 2022 stratifies these MR gene mutations into the adverse-risk group. By thoroughly annotating a cohort of 344 newly diagnosed patients with AML treated at the Memorial Sloan Kettering Cancer Center, we show that ontogeny assignments based on the database registry lack accuracy. MR gene mutations are frequently observed in de novo AML. Among the MR gene mutations, only EZH2 and SF3B1 were associated with an inferior outcome in the univariate analysis. In a multivariate analysis, AML ontogeny had independent prognostic values even after adjusting for age, treatment, allo-transplant and genomic classes or ELN risks. Ontogeny also helped stratify the outcome of AML with MR gene mutations. Finally, de novo AML with MR gene mutations did not show an adverse outcome. In summary, our study emphasizes the importance of accurate ontogeny designation in clinical studies, demonstrates the independent prognostic value of AML ontogeny, and questions the current classification and risk stratification of AML with MR gene mutations.

Comparison of TP53 Mutations in Myelodysplasia and Acute Leukemia Suggests Divergent Roles in Initiation and Progression

TP53 mutation predicts adverse prognosis in many cancers, including myeloid neoplasms, but the mechanisms by which specific mutations impact disease biology, and whether they differ between disease categories, remain unknown. We analyzed TP53 mutations in four myeloid neoplasm subtypes (MDS, AML, AML with myelodysplasia-related changes (AML-MRC), and therapy-related acute myeloid leukemia (tAML)), and identified differences in mutation types, spectrum, and hotspots between disease categories and compared to solid tumors. Missense mutations in the DNA-binding domain were most common across all categories, whereas inactivating mutations and mutations outside the DNA binding domain were more common in AML-MRC compared to MDS. TP53 mutations in MDS were more likely to retain transcriptional activity, and co-mutation profiles were distinct between disease categories and mutation types. Our findings suggest that mutated TP53 contributes to initiation and progression of neoplasia via distinct mechanisms, and support the utility of specific identification of TP53 mutations in myeloid malignancies.

p53 as Exemplar Next-Generation Immunohistochemical Marker: A Molecularly Informed, Pattern-Based Approach, Methodological Considerations, and Pan-Cancer Diagnostic Applications

This review is based on a webinar I presented for the International Society for Immunohistochemistry and Molecular Morphology (ISIMM) in February 2022. It is intended that all ISIMM webinars will ultimately be published in AIMM as review articles. This work is also dedicated to Clive Taylor, who has deeply impacted my career. It presents a molecularly informed, pattern-based approach to p53 immunohistochemistry interpretation, methodological considerations (ie, antibody selection, optimization, validation, controls, and external quality assessment), and pan-cancer diagnostic applications, including those drawn from gastrointestinal, genitourinary, gynecological, neuroendocrine, hematologic, and neuropathology. It intends to prove the thesis statement that p53 is an exemplar next-generation immunohistochemical marker "born" ahead of its time.

TP53-Mutated Myelodysplasia and Acute Myeloid Leukemia

TP53-mutated myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) form a distinct and heterogeneous group of myeloid malignancies associated with poor outcomes. Studies carried out in the last years have in part elucidated the complex role played by TP53 mutations in the pathogenesis of these myeloid disorders and in the mechanisms of drug resistance. A consistent number of studies has shown that some molecular parameters, such as the presence of a single or multiple TP53 mutations, the presence of concomitant TP53 deletions, the association with co-occurring mutations, the clonal size of TP53 mutations, the involvement of a single (monoallelic) or of both TP53 alleles (biallelic) and the cytogenetic architecture of concomitant chromosome abnormalities are major determinants of outcomes of patients. The limited response of these patients to standard treatments, including induction chemotherapy, hypomethylating agents and venetoclax-based therapies and the discovery of an immune dysregulation have induced a shift to new emerging therapies, some of which being associated with promising efficacy. The main aim of these novel immune and nonimmune strategies consists in improving survival and in increasing the number of TP53-mutated MDS/AML patients in remission amenable to allogeneic stem cell transplantation.

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.

AML classification in the year 2023: How to avoid a Babylonian confusion of languages

In parallel to the 5th edition of the World Health Organization Classification of Haematolymphoid Tumours (WHO 2022), an alternative International Consensus Classification (ICC) has been proposed. To evaluate the impact of the new classifications on AML diagnoses and ELN-based risk classification, we analyzed 717 MDS and 734 AML non-therapy-related patients diagnosed according to the revised 4th WHO edition (WHO 2017) by whole genome and transcriptome sequencing. In both new classifications, the purely morphologically defined AML entities decreased from 13% to 5%. Myelodysplasia-related (MR) AML increased from 22% to 28% (WHO 2022) and 26% (ICC). Other genetically-defined AML remained the largest group, and the abandoned AML-RUNX1 was mainly reclassified as AML-MR (WHO 2022: 77%; ICC: 96%). Different inclusion criteria of AML-CEBPA and AML-MR (i.a. exclusion of TP53 mutated cases according to ICC) were associated with differences in overall survival. In conclusion, both classifications focus on more genetics-based definitions with similar basic concepts and a large degree of agreement. The remaining non-comparability (e.g., TP53 mutated AML) needs additional studies to definitely answer open questions on disease categorization in an unbiased way.

A Phase I study of Milademetan (DS3032b) in combination with low dose cytarabine with or without venetoclax in acute myeloid leukemia: Clinical safety, efficacy, and correlative analysis

In TP53 wild-type acute myeloid leukemia (AML), inhibition of MDM2 can enhance p53 protein expression and potentiate leukemic cell apoptosis. MDM2 inhibitor (MDM2i) monotherapy in AML has shown modest responses in clinical trials but combining options of MDM2i with other potent AML-directed agents like cytarabine and venetoclax could improve its efficacy. We conducted a phase I clinical trial (NCT03634228) to study the safety and efficacy of milademetan (an MDM2i) with low-dose cytarabine (LDAC)±venetoclax in adult patients with relapsed refractory (R/R) or newly diagnosed (ND; unfit) TP53 wild-type AML and performed comprehensive CyTOF analyses to interrogate multiple signaling pathways, the p53-MDM2 axis and the interplay between pro/anti-apoptotic molecules to identify factors that determine response and resistance to therapy. Sixteen patients (14 R/R, 2 N/D treated secondary AML) at a median age of 70 years (range, 23-80 years) were treated in this trial. Two patients (13%) achieved an overall response (complete remission with incomplete hematological recovery). Median cycles on trial were 1 (range 1-7) and at a median follow-up of 11 months, no patients remained on active therapy. Gastrointestinal toxicity was significant and dose-limiting (50% of patients ≥ grade 3). Single-cell proteomic analysis of the leukemia compartment revealed therapy-induced proteomic alterations and potential mechanisms of adaptive response to the MDM2i combination. The response was associated with immune cell abundance and induced the proteomic profiles of leukemia cells to disrupt survival pathways and significantly reduced MCL1 and YTHDF2 to potentiate leukemic cell death. The combination of milademetan, LDAC±venetoclax led to only modest responses with recognizable gastrointestinal toxicity. Treatment-induced reduction of MCL1 and YTHDF2 in an immune-rich milieu correlate with treatment response.

TP53 Mutations in AML Patients Are Associated with Dismal Clinical Outcome Irrespective of Frontline Induction Regimen and Allogeneic Hematopoietic Cell Transplantation

TP53 mutations are associated with extremely poor outcomes in acute myeloid leukemia (AML). The outcomes of patients with TP53-mutated (TP53^MUT) AML after different frontline treatment modalities are not well established. Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative procedure for AML; however, long-term outcomes among patients with TP53^MUT AML after allo-HCT are dismal, and the benefit of allo-HCT remains controversial. We sought to evaluate the outcomes of patients with TP53^MUT AML after treatment with different frontline induction therapies and allo-HCT. A total of 113 patients with TP53^MUT AML were retrospectively evaluated. Patients with TP53^MUT AML who received intensive or azacitidine-venetoclax induction had higher complete remission rates compared to patients treated with other hypomethylating-agent-based induction regimens. However, OS and EFS were not significantly different among the induction regimen groups. Allo-HCT was associated with improved OS and EFS among patients with TP53^MUT AML; however, allo-HCT was not significantly associated with improved OS or EFS in time-dependent or landmark analysis. While the outcomes of all patients were generally poor irrespective of therapeutic strategy, transplanted patients with lower TP53^MUT variant allele frequency (VAF) at the time of diagnosis had superior outcomes compared to transplanted patients with higher TP53 VAF. Our study provides further evidence that the current standards of care for AML confer limited therapeutic benefit to patients with TP53 mutations.

TP53 mutation variant allele frequency of ≥10% is associated with poor prognosis in therapy-related myeloid neoplasms

Revised diagnostic criteria for myeloid neoplasms (MN) issued by the International Consensus Classification (ICC) and the World Health Organization (WHO) recommended major change pertaining to TP53-mutated (TP53mut) MN. However, these assertions have not been specifically examined in therapy-related myeloid neoplasm (t-MN), a subset enriched with TP53mut. We analyzed 488 t-MN patients for TP53mut. At least one TP53mut with variant allele frequency (VAF) ≥ 2% with or without loss of TP53 locus was noted in 182 (37.3%) patients and 88.2% of TP53mut t-MN had a VAF ≥10%. TP53mut t-MN with VAF ≥ 10% had a distinct clinical and biological profile compared to both TP53mut VAF < 10% and wild-type TP53 (TP53wt) cases. Notably, TP53mut VAF ≥ 10% had a significantly shorter survival compared to TP53wt (8.3 vs. 21.6 months; P < 0.001), while the survival of TP53mut VAF < 10% was comparable to TP53wt. Within TP53mut VAF ≥ 10% cohort, the inferior outcomes persisted irrespective of the single- or multi-hit status, co-mutation pattern, or treatments received. Finally, survival of TP53mut patients was poor across all the blast categories and MDS patients with >10% blasts had inferior survival compared to <5%. In summary, TP53mut VAF ≥10% signified a clinically and molecularly homogenous cohort regardless of the allelic status.

Recent advances in targeted therapies in acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. While survival for younger patients over the last several decades has improved nearly sixfold with the optimization of intensive induction chemotherapy and allogeneic stem cell transplantation (alloHSCT), this effect has been largely mitigated in older and less fit patients as well as those with adverse-risk disease characteristics. However, the last 10 years has been marked by major advances in the molecular profiling of AML characterized by a deeper understanding of disease pathobiology and therapeutic vulnerabilities. In this regard, the classification of AML subtypes has recently evolved from a morphologic to a molecular and genetic basis, reflected by recent updates from the World Health Organization and the new International Consensus Classification system. After years of stagnation in new drug approvals for AML, there has been a rapid expansion of the armamentarium against this disease since 2017. Low-intensity induction therapy with hypomethylating agents and venetoclax has substantially improved outcomes, including in those previously considered to have a poor prognosis. Furthermore, targeted oral therapies against driver mutations in AML have been added to the repertoire. But with an accelerated increase in treatment options, several questions arise such as how to best sequence therapy, how to combine therapies, and if there is a role for maintenance therapy in those who achieve remission and cannot undergo alloHSCT. Moreover, certain subtypes of AML, such as those with TP53 mutations, still have dismal outcomes despite these recent advances, underscoring an ongoing unmet need and opportunity for translational advances. In this review, we will discuss recent updates in the classification and risk stratification of AML, explore the literature regarding low-intensity and novel oral combination therapies, and briefly highlight investigative agents currently in early clinical development for high-risk disease subtypes.

Molecular characterization and prognosis of mutant TP53 acute myeloid leukemia and myelodysplastic syndrome with excess blasts

INTRODUCTION

Myeloid tumors typically harbor TP53 mutations, which are linked to a dismal prognosis. There are fewer studies on whether TP53-mutated acute myeloid leukemia (AML) and myelodysplastic syndrome with excess blasts (MDS-EB) differ in molecular characteristics and should be considered as separate entities.

METHODS

Between January 2016 and December 2021, a retrospective analysis was done on a total of 73 newly diagnosed AML patients and 61 MDS-EB patients from the first affiliated hospital of Soochow University. We described a survival profile and a thorough characterization of newly found TP53-mutant AML and MDS-EB and investigated the relationship between these characteristics and overall survival (OS).

RESULTS

38 (31.1%) were mono-allelic, and 84 (68.9%) were bi-allelic. There is no significant difference between TP53-mutated AML and MDS-EB (median OS 12.9 verse 14.4 months; p = .558). Better overall survival was linked to mono-allelic TP53 than bi-allelic TP53(HR = 3.030, CI:1.714-5.354, p < .001). However, the number of TP53 mutations and comutations were not significantly associated with OS. TP53 variant allele frequency cutoff of 50% is significant correlation with OS (HR: 2.177, 95% CI: 1.142-4.148; p = .0063).

CONCLUSION

Our data revealed that allele status and allogeneic hematopoietic stem cell transplant independently affect the prognostic of AML and MDS-EB patients, with a concordance of molecular features and survival between these two disease entities. Our analysis favors considering TP53-mutated AML/MDS-EB as a distinct disorder.

Comparison of the International Consensus and 5th WHO edition classifications of adult myelodysplastic syndromes and acute myeloid leukemia

Several editions of the World Health Organization (WHO) classifications of lympho-hemopoietic neoplasms in 2001, 2008, and 2016 served as the international standard for diagnosis. Since the 4th WHO edition, here referred as WHO-HAEM4, significant clinico-pathological, immunophenotypic, and molecular advances have been made in the field of myeloid neoplasms, which have contributed to refine diagnostic criteria, to upgrade entities previously defined as provisional and to identify new entities. This process has resulted in two recent classification proposals of myeloid neoplasms: the International Consensus Classification (ICC) and the 5th edition of the WHO classification (WHO-HAEM5). In this paper, we review and compare the two classifications in terms of diagnostic criteria and entity definition, with a focus on adult myelodysplastic syndromes/neoplasms (MDS) and acute myeloid leukemia (AML). The goal is to provide a tool to facilitate the work of pathologists, hematologists and researchers involved in the diagnosis and treatment of these hematological malignancies.