TP53 immunohistochemistry correlates with TP53 mutation status and clearance in decitabine-treated patients with myeloid malignancies

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.

A line in shifting sand: Can we define and target TP53 mutated MDS?

Mutations in the tumor suppressor protein, TP53, lead to dismal outcomes in myeloid malignancies, including myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Recent pathological reclassifications have integrated TP53 mutated MDS and AML under a unified category of TP53 mutated myeloid neoplasms, which allows for more flexibility in treatment approaches. Therapeutic strategies have predominantly mirrored those for AML, with allogeneic stem cell transplantation emerging as critical for long-term disease control. The question remains whether there are physiological distinctions within TP53 mutated myeloid neoplasms that will significantly impact prognosis and therapeutic considerations. This review explores the unique aspects of classically defined "TP53 mutated MDS", focusing on its distinct biological characteristics and outcomes. Our current understanding is that TP53 mutated MDS and AML are globally quite similar, but as a group have unique features compared to TP53 wildtype (WT) disease. Optimizing immunotherapy and targeting vulnerabilities due to co-mutations and/or chromosome abnormalities should be the focus of future research.

p53 Abnormal Oral Epithelial Dysplasias are Associated With High Risks of Progression and Local Recurrence-A Retrospective Study in a Longitudinal Cohort

Grading of oral epithelial dysplasia (OED) can be challenging with considerable intraobserver and interobserver variability. Abnormal immunohistochemical staining patterns of the tumor suppressor protein, p53, have been recently shown to be potentially associated with progression in OED. We retrospectively identified 214 oral biopsies from 203 patients recruited in a longitudinal study between 2001 and 2008 with a diagnosis of reactive, nondysplastic lesions, low-grade lesions (mild OED and moderate OED) and high-grade lesions (HGLs; severe OED/carcinoma in situ). Tissue microarrays were constructed from the most representative area of the pathology. Three consecutive sections were sectioned and stained for hematoxylin and eosin, p53 immunohistochemistry, and p16 immunohistochemistry. The staining results were reviewed by 2 pathologists (Y.C.K.K., C.F.P.) blinded to clinical outcome. Samples were categorized into p53 abnormal OED (n = 46), p53 conventional OED (n = 118), and p53 human papillomavirus (HPV) OED (HPV associated) (n = 12) using a previously published pattern-based approach. All cases of p53 HPV OED (HPV associated) were identified in HGLs. In contrast, cases of p53 abnormal OED were observed in mild OED (9.5%), moderate OED (23%), and severe OED/carcinoma in situ (51%). None of the 27 reactive or nondysplastic lesions showed abnormal p53 staining patterns. Among the 135 low-grade lesions, 23 cases (17.0%; 2 mild OEDs and 21 moderate OEDs) progressed to HGL or squamous cell carcinoma, with 11 cases showing progression within the first 3 years. Remarkably, 82% (9/11) of these faster progressors showed abnormal p53 patterns. Survival analysis revealed that p53 abnormal OED had significantly poorer progression-free probability (P < .0001) with hazard ratio of 11.24 (95% CI, 4.26-29.66) compared with p53 conventional OED. Furthermore, p53 abnormal OED had poorer local recurrence-free survival compared with p53 wild-type OED (P = .03). The study supports that OED with p53 abnormal pattern is at high risk for progression and recurrence independent of the dysplasia grade.

From regulation to deregulation of p53 in hematologic malignancies: implications for diagnosis, prognosis and therapy

The p53 protein, encoded by the TP53 gene, serves as a critical tumor suppressor, playing a vital role in maintaining genomic stability and regulating cellular responses to stress. Dysregulation of p53 is frequently observed in hematological malignancies, significantly impacting disease progression and patient outcomes. This review aims to examine the regulatory mechanisms of p53, the implications of TP53 mutations in various hematological cancers, and emerging therapeutic strategies targeting p53. We conducted a comprehensive literature review to synthesize recent findings related to p53's multifaceted role in hematologic cancers, focusing on its regulatory pathways and therapeutic potential. TP53 mutations in hematological malignancies often lead to treatment resistance and poor prognosis. Current therapeutic strategies, including p53 reactivation and gene therapy, show promise in improving treatment outcomes. Understanding the intricacies of p53 regulation and the consequences of its mutations is essential for developing effective diagnostic and therapeutic strategies in hematological malignancies, ultimately enhancing patient care and survival.

TP53 mutations in myeloid neoplasms: implications for accurate laboratory detection, diagnosis, and treatment

Genetic alterations that affect the function of p53 tumor suppressor have been extensively investigated in myeloid neoplasms, revealing their significant impact on disease progression, treatment response, and patient outcomes. The identification and characterization of TP53 mutations play pivotal roles in subclassifying myeloid neoplasms and guiding treatment decisions. Starting with the presentation of a typical case, this review highlights the complicated nature of genetic alterations involving TP53 and provides a comprehensive analysis of TP53 mutations and other alterations in myeloid neoplasms. Currently available methods used in clinical laboratories to identify TP53 mutations are discussed, focusing on the importance of establishing a robust testing protocol within clinical laboratories to ensure the delivery of accurate and reliable results. The treatment implications of TP53 mutations in myeloid neoplasms and clinical trial options are reviewed. Ultimately, we hope that this review provides valuable insights into the patterns of TP53 alterations in myeloid neoplasms and offers guidance to establish practical laboratory testing protocols to support the best practices of precision oncology.

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.

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.

Recurrent Oropharyngeal Squamous Cell Carcinomas Maintain Anti-tumor Immunity and Multinucleation Levels Following Completion of Radiation

OBJECTIVE

Oropharyngeal squamous cell carcinoma (OPSCC) recurrence is almost universally fatal. Development of effective therapeutic options requires an improved understanding of recurrent OPSCC biology.

METHODS

We analyzed paired primary-recurrent OPSCC from Veterans treated at the Michael E. DeBakey Veterans Affairs Medical Center between 2000 and 2020 who received curative intent radiation-based treatment (with or without chemotherapy). Patient tumors were analyzed using standard immunohistochemistry and automated imaging of infiltrating lymphocytes and multinucleated tumor cells coupled to machine learning algorithms.

RESULTS

Primary and recurrent tumors demonstrated high concordance via p16 and p53 immunohistochemistry, with comparable levels of multinucleation. In contrast, recurrent tumors demonstrated significantly higher levels of CD8+ tumor infiltrating lymphocytes (p<0.05) and higher levels of PD-L1 expression (p<0.05).

CONCLUSION

Exposure to chemo-radiation and recurrence following treatment preserves critical features of intrinsic tumor biology and the tumor immune microenvironment suggesting that novel treatment regimens may be as effective in the salvage setting as in the definitive intent setting.

The Pathology according to p53 Pathway

BACKGROUND

Observations play a pivotal role in the progress of science, including in pathology. The cause of a disease such as cancer is analyzed by breaking it down into smaller organs, tissues, cells, and molecules. The current standard cancer diagnostic procedure, microscopic observation, relies on preserved morphological characteristics. In contrast, molecular analyses explore oncogenic pathway activation that leads to genetic mutations and aberrant protein expression. Such molecular analyses could potentially identify therapeutic targets and has gained considerable attention in clinical oncology.

SUMMARY

This review summarizes the cardinal biomarkers of the p53 pathway, p53, p16, and mouse double minute 2 (MDM2), in the context of traditional surgical pathology and emerging genomic oncology. The p53 pathway, which is dysregulated in more than a half of all cancers, can be applied in several diagnostic settings. A four-classification model of immunophenotype for p53 pathway gene status, tumor types with a high frequency of abnormalities for each p53 pathway gene, and a minimal p53 pathway immunohistochemical panel is also described.

KEY MESSAGES

Immunohistochemistry of oncogenic signals should be interpreted according to molecular findings based on genomic oncology, in addition to the microscopic findings of diagnostic pathology.

Recurrent oropharyngeal squamous cell carcinomas maintain anti-tumor immunity and multinucleation levels following completion of radiation

Objective

Oropharyngeal squamous cell carcinoma (OPSCC) recurrence is almost universally fatal. Development of effective therapeutic options requires an improved understanding of recurrent OPSCC biology.

Methods

We analyzed paired primary-recurrent OPSCC from Veterans treated at the Michael E. DeBakey Veterans Affairs Medical Center between 2000 and 2020 who received curative intent radiation-based treatment (with or without chemotherapy). Patient tumors were analyzed using standard immunohistochemistry and automated imaging of infiltrating lymphocytes and multinucleated tumor cells coupled to machine learning algorithms.

Results

Primary and recurrent tumors demonstrated high concordance via p16 and p53 immunohistochemistry, with comparable levels of multinucleation. In contrast, recurrent tumors demonstrated significantly higher levels of CD8+ tumor infiltrating lymphocytes (p<0.05) and higher levels of PD-L1 expression (p<0.05).

Conclusion

Exposure to chemo-radiation and recurrence following treatment does not appear deleterious to underlying biological characteristics and anti-tumor immunity of oropharyngeal cancer, suggesting that novel treatment regimens may be as effective in the salvage setting as in the definitive intent setting.

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 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.

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.

Distinct clonal identities of B-ALLs arising after lenolidomide therapy for multiple myeloma

Patients with multiple myeloma (MM) who are treated with lenalidomide rarely develop a secondary B-cell acute lymphoblastic leukemia (B-ALL). The clonal and biological relationship between these sequential malignancies is not yet clear. We identified 17 patients with MM treated with lenalidomide, who subsequently developed B-ALL. Patient samples were evaluated through sequencing, cytogenetics/fluorescence in situ hybridization (FISH), immunohistochemical (IHC) staining, and immunoglobulin heavy chain (IgH) clonality assessment. Samples were assessed for shared mutations and recurrently mutated genes. Through whole exome sequencing and cytogenetics/FISH analysis of 7 paired samples (MM vs matched B-ALL), no mutational overlap between samples was observed. Unique dominant IgH clonotypes between the tumors were observed in 5 paired MM/B-ALL samples. Across all 17 B-ALL samples, 14 (83%) had a TP53 variant detected. Three MM samples with sufficient sequencing depth (>500×) revealed rare cells (average of 0.6% variant allele frequency, or 1.2% of cells) with the same TP53 variant identified in the subsequent B-ALL sample. A lack of mutational overlap between MM and B-ALL samples shows that B-ALL developed as a second malignancy arising from a founding population of cells that likely represented unrelated clonal hematopoiesis caused by a TP53 mutation. The recurrent variants in TP53 in the B-ALL samples suggest a common path for malignant transformation that may be similar to that of TP53-mutant, treatment-related acute myeloid leukemia. The presence of rare cells containing TP53 variants in bone marrow at the initiation of lenalidomide treatment suggests that cellular populations containing TP53 variants expand in the presence of lenalidomide to increase the likelihood of B-ALL development.

Utilizing digital pathology and immunohistochemistry of p53 as an adjunct to molecular testing in myeloid disorders

TP53 mutation status guides early therapeutic decisions in the treatment of clonal myeloid disorders and serves as a simple means of monitoring response to treatment. We aim here to develop a standardized protocol for evaluating TP53 mutation status in myeloid disorders using immunohistochemistry assisted by digital image analysis and further compare this approach to manual interpretation alone. To accomplish this, we obtained 118 bone marrow biopsies from patients with hematologic malignancy and molecular testing for mutations associated with acute myeloid leukemia was performed. Clot or core biopsy slides were stained for p53 and digitally scanned. Overall mutation burden was assessed digitally using two different metrics to determine positivity, compared to the results of manual review, and correlated with molecular results. Using this approach, we found that digital analysis of immunohistochemistry stained slides performed worse than manual categorization alone in predicting TP53 mutation status in our cohort (PPV 91%, NPV 100% vs. PPV 100%, NPV 98%). While digital analysis reduced inter- and intraobserver variability when assessing mutation burden, there was poor correlation between the quantity and intensity of p53 staining and molecular analysis (R2 = 0.204). Therefore, digital image analysis of p53 immunohistochemistry accurately predicts TP53 mutation status as confirmed by molecular testing but does not offer a significant advantage over manual categorization alone. However, this approach offers a highly standardized methodology for monitoring disease status or response to treatment once a diagnosis has been made.

Genomic profiling for clinical decision making in myeloid neoplasms and acute leukemia

Myeloid neoplasms and acute leukemias derive from the clonal expansion of hematopoietic cells driven by somatic gene mutations. Although assessment of morphology plays a crucial role in the diagnostic evaluation of patients with these malignancies, genomic characterization has become increasingly important for accurate diagnosis, risk assessment, and therapeutic decision making. Conventional cytogenetics, a comprehensive and unbiased method for assessing chromosomal abnormalities, has been the mainstay of genomic testing over the past several decades and remains relevant today. However, more recent advances in sequencing technology have increased our ability to detect somatic mutations through the use of targeted gene panels, whole-exome sequencing, whole-genome sequencing, and whole-transcriptome sequencing or RNA sequencing. In patients with myeloid neoplasms, whole-genome sequencing represents a potential replacement for both conventional cytogenetic and sequencing approaches, providing rapid and accurate comprehensive genomic profiling. DNA sequencing methods are used not only for detecting somatically acquired gene mutations but also for identifying germline gene mutations associated with inherited predisposition to hematologic neoplasms. The 2022 International Consensus Classification of myeloid neoplasms and acute leukemias makes extensive use of genomic data. The aim of this report is to help physicians and laboratorians implement genomic testing for diagnosis, risk stratification, and clinical decision making and illustrates the potential of genomic profiling for enabling personalized medicine in patients with hematologic neoplasms.

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

Mutant TP53 is an adverse risk factor in acute myeloid leukemia (AML), but large-scale integrated genomic-proteomic analyses of TP53 alterations in patients with AML remain limited. We analyzed TP53 mutational status, copy number (CN), and protein expression data in AML (N = 528) and provide a compilation of mutation sites and types across disease subgroups among treated and untreated patients. Our analysis shows differential hotspots in subsets of AML and uncovers novel pathogenic variants involving TP53 splice sites. In addition, we identified TP53 CN loss in 70.2% of TP53-mutated AML cases, which have more deleterious TP53 mutations, as well as copy neutral loss of heterozygosity in 5/32 (15.6%) AML patients who had intact TP53 CN. Importantly, we demonstrate that mutant p53 protein expression patterns by immunohistochemistry evaluated using digital image-assisted analysis provide a robust readout that integrates TP53 mutation and allelic states in patients with AML. Expression of p53 by immunohistochemistry informed mutation status irrespective of TP53 CN status. Genomic analysis of comutations in TP53-mutant AML shows a muted landscape encompassing primarily mutations in genes involved in epigenetic regulation (DNMT3A and TET2), RAS/MAPK signaling (NF1, KRAS/NRAS, PTPN11), and RNA splicing (SRSF2). In summary, our data provide a rationale to refine risk stratification of patients with AML on the basis of integrated molecular and protein-level TP53 analyses.

Lymphocytic Infiltrate and p53 Protein Expression as Predictive Markers of Response and Outcome in Myelodysplastic Syndromes Treated with Azacitidine

High-risk Myelodysplastic syndromes (MDS) represent therapeutical challenges and are usually managed with hypomethylating agents such as azacitidine. Given the lack of data in the literature concerning azacitidine effects on bone marrow, we retrospectively analyzed 57 high-risk MDS cases in order to identify any changes induced by azacitidine therapy or relevant correlations between therapy response and pre- or post-treatment features. Azacitidine treatment had no significant impact on bone marrow cellularity or morphological dysplastic features. On the contrary, although not statistically significant, we observed a slight decrease in CD34+ and CD117+ blasts and p53+ precursors after treatment. Moreover, pre-treatment IPSS-R cytogenetic score (p = 0.004), lymphocytic infiltrate (p = 0.017) and p53+ elements (p = 0.001) correlated with AML progression; pre-treatment lymphocytic infiltrate was also linked to better response to therapy (p = 0.004), suggesting an anti-tumoral role of bone marrow microenvironment. Post-treatment blast count impacted negatively on overall survival (p = 0.035) and risk of leukemic progression (p = 0.04), while both post-treatment lymphocytic infiltrate and p53+ elements showed significant correlation with treatment response (p = 0.004 and p = 0.003 respectively). Higher post-treatment p53+ elements correlated also with risk of leukemic progression (p = 0.013). Our results suggest the possible role of lymphocytic infiltrate and p53+ elements as predictive markers in MDS treated with azacitidine, disclosing new chapters in the understanding of MDS evolution and treatment.

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.