Remission of hypersensitivity pneumonitis after allogeneic hematopoietic stem cell transplantation.

A 50-year-old man was diagnosed with hypersensitivity pneumonitis caused by the environment of his bar owing to worsening symptoms, laboratory test results, and computed tomography images after an environmental inhalation challenge test. His hypersensitivity pneumonitis exacerbated despite receiving prednisolone 20 mg/day. The patient underwent allogeneic hematopoietic stem cell transplantation (HSCT) from a human leukocyte antigen-matched unrelated donor for myelodysplastic syndrome. No exacerbation of hypersensitivity pneumonitis was observed after HSCT. An environmental inhalation challenge test involving exposure to his bar confirmed the remission of hypersensitivity pneumonitis after HSCT. This case demonstrates that hypersensitivity pneumonitis can be remitted by HSCT.

Myelodysplastic syndrome occurring after enfortumab vedotin treatment for metastatic urothelial carcinoma.

Introduction: Enfortumab vedotin is an antibody-drug conjugate targeting Nectin-4 for the treatment of advanced urothelial carcinoma in patients previously treated with platinum-containing chemotherapy and immune checkpoint inhibitors. Common adverse events include rashes, peripheral neuropathy, and hyperglycemia. However, there are no reports on the development of myelodysplastic syndrome during enfortumab vedotin therapy in clinical settings. Case presentation: A 72-year-old male patient experienced prolonged and severe thrombocytopenia 18 weeks after the start of enfortumab vedotin therapy for metastatic urothelial carcinoma, requiring daily platelet transfusions. Bone marrow examination and chromosomal analysis confirmed the diagnosis of myelodysplastic syndrome. Treatment with eltrombopag proved to be effective. Conclusion: This is the first report of the development of myelodysplastic syndrome during enfortumab vedotin therapy in a clinical setting. Although rare, myelodysplastic syndrome can occur during enfortumab vedotin therapy.

WT1 gene mutations impact post-transplant relapse in myelodysplastic syndrome with excess blasts 2 patients.

Wilms tumor 1 (WT1) gene mutations are infrequent in myelodysplastic syndrome (MDS), but MDS with WT1 mutations (WT1mut) is considered high risk for acute myeloid leukemia (AML) transformation. The influence of WT1 mutations in patients with MDS after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is unclear. We performed a retrospective analysis of 136 MDS with excess blasts 2 (MDS-EB2) patients with available WT1 status who underwent their first allo-HSCT between 2017 and 2022 in our center. There were 20 (20/136, 15%) cases in the WT1mut group and 116 (116/136, 85%) cases in the WT1 wild-type (WT1wt) group. WT1mut patients had a higher 2-year cumulative incidence of relapse (CIR) than WT1wt cases (26.2% vs. 9.4%, p = 0.037) after allo-HSCT. Multivariate analysis of relapse showed that WT1 mutations (HR, 6.0; p = 0.002), TP53 mutations (HR, 4.2; p = 0.021), and ≥ 5% blasts in bone marrow (BM) at transplantation (HR, 6.6; p = 0.004) were independent risk factors for relapse. Patients were stratified into three groups according to the risk factors. Two-year CIR differed significantly in high-, intermediate-, and low-risk groups (31.8%, 11.6%, and 0%, respectively). Hence, WT1 mutations may be related to post-transplant relapse in patients with MDS-EB2, which warrants further study.

A comparison of WHO-5 and ICC classifications in a series of myeloid neoplasms, considerations for hematopathologists and molecular pathologists.

OBJECTIVES: The International Consensus Classification (ICC) and 5th Edition of the World Health Organization Classification (WHO-5) made substantive updates to the classification of myeloid neoplasms. This study compares the systems in a series of myeloid neoplasms with increased blasts, analyzing implications for diagnostic workflow and reporting. METHODS: Bone marrow biopsies categorized as myelodysplastic syndrome with excess blasts (MDS-EB) or acute myeloid leukemia (AML) by WHO-R4 were identified. Results of morphology review, karyotype, fluorescence in situ hybridization, and next-generation sequencing were compiled. Cases were retrospectively re-classified by WHO-5 and ICC. RESULTS: 46 cases were reviewed. 28 cases (61 %) had ≥20 % blasts, with the remaining cases having 5-19.5 % blasts. The most common differences in classification were 1) the designation of MDS versus MDS/AML (10/46, 22 %) for cases with 10-19 % blasts and 2) the ICC's designation of TP53 variants as a separate classifier for AML (8/46, 17 %). Bi-allelic/multi-hit TP53 alterations were identified in 15 cases (33 %). Variants of potential germline significance were identified in 29 (63 %) cases. CONCLUSIONS: While terminology differences between WHO-5 and ICC exist, both systems invoke similar opportunities for improved reporting: standardized classification of pathogenic variants (notably TP53), streamlined systems to evaluate for potential germline variants, and integrated reporting of morphologic and genetic data.

[Analysis of the efficacy and prognostic factors of allogeneic hematopoietic stem cell transplantation in patients with myelodysplastic syndrome with blastomycosis and survival comparison of different subtypes after the WHO 2022 reclassification].

Objective: To evaluate the efficacy and prognostic factors of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with myelodysplastic syndrome accompanied by myelodysplasia (MDS-EB) and to compare the prognosis of different subtypes of patients classified by World Health Organization (WHO) 2022. Methods: A total of 282 patients with MDS-EB who underwent allo-HSCT at the Hematology Hospital of the Chinese Academy of Medical Sciences from October 2006 to December 2022 were included in the study. The WHO 2022 diagnostic criteria reclassified MDS into three groups: myelodysplastic tumors with type 1/2 of primitive cell proliferation (MDS-IB1/IB2, 222 cases), MDS with fibrosis (MDS-f, 41 cases), and MDS with biallelic TP53 mutation (MDS-biTP53, 19 cases). Their clinical data were retrospectively analyzed. Results: ① The median age of 282 patients was 46 (15-66) years, with 191 males and 91 females. Among them, 118 (42% ) and 164 (58% ) had MDS-EB1 and MDS-EB2, respectively. ②Among the 282 patients, 256 (90.8% ) achieved hematopoietic reconstruction after transplantation, with 11 (3.9% ) and 15 (5.3% ) having primary and secondary implantation dysfunctions, respectively. The cumulative incidence of acute graft-versus-host disease (GVHD) 100 days post-transplantation was (42.6±3.0) %, and the cumulative incidence of grade Ⅱ-Ⅳ acute GVHD was (33.0±2.8) %. The cumulative incidence of chronic GVHD 1 year post-transplantation was (31.0±2.9) %. Post-transplantation, 128 (45.4% ), 63 (22.3% ), 35 (12.4% ), and 17 patients (6.0% ) developed cytomegalovirus infection, bacteremia, pulmonary fungal infection, and Epstein-Barr virus infection. ③The median follow-up time post-transplantation was 22.1 (19.2-24.7) months, and the 3-year overall survival (OS) and disease-free survival (DFS) rates were 71.9% (95% CI 65.7% -78.6% ) and 63.6% (95% CI 57.2% -70.7% ), respectively. The 3-year non-recurrent mortality rate (NRM) is 17.9% (95% CI 13.9% -22.9% ), and the 3-year cumulative recurrence rate (CIR) is 9.8% (95% CI 6.7% -13.7% ). The independent risk factors affecting OS post-transplantation include monocyte karyotype (P=0.004, HR=3.26, 95% CI 1.46-7.29), hematopoietic stem cell transplantation complication index (HCI-CI) of ≥3 points (P<0.001, HR=2.86, 95% CI 1.72-4.75), and the occurrence of acute gastrointestinal GVHD of grade Ⅱ-Ⅳ (P<0.001, HR=5.94, 95% CI 3.50-10.10). ④The 3-year OS and DFS rates in the MDS-IB1/IB2 group post-transplantation were better than those in the MDS-biTP53 group [OS: 72.0% (95% CI 63.4% -80.7% ) vs 46.4% (95% CI 26.9% -80.1% ), P=0.020; DFS: 67.4% (95% CI 60.3% -75.3% ) vs 39.7% (95% CI 22.3% -70.8% ), P=0.015]. The 3-year CIR was lower than that of the MDS-biTP53 group [7.3% (95% CI 4.3% -11.4% ) vs 26.9% (95% CI 9.2% -48.5% ), P=0.004]. The NRM at 3 years post-transplantation in the MDS-IB1/IB2, MDS-f, and MDS-biTP53 groups were 16.7% (95% CI 12.1% -22.1% ), 20.5% (95% CI 9.4% -34.6% ), and 26.3% (95% CI 9.1% -47.5% ), respectively (P=0.690) . Conclusion: Allo-HSCT is an effective treatment for MDS-EB, with monomeric karyotype, HCI-CI, and grade Ⅱ-Ⅳ acute gastrointestinal GVHD as independent risk factors affecting the patient's OS. The WHO 2022 classification helps distinguish the efficacy of allo-HSCT in different subgroups of patients. Allo-HSCT can improve the poor prognosis of patients with MDS-f, but those with MDS-biTP53 have a higher risk of recurrence post-transplantation.

Subsequent Malignancies after CD19-Targeted Chimeric Antigen Receptor T cells in Patients with Lymphoma.

Chimeric antigen receptor (CAR) T cells are an established treatment for B cell non-Hodgkin lymphomas (B-NHL). With the remarkable success in improving survival, understanding the late effects of CAR T cell therapy is becoming more relevant. The aim of this study is to determine the incidence of subsequent malignancies in adult patients with B-NHL. We retrospectively studied 355 patients from two different medical centers treated with four different CAR T cell products from 2016 to 2022. The overall cumulative incidence for subsequent malignancies at 36 months was 14% (95% CI: 9.2%, 19%). Subsequent malignancies were grouped into three primary categories: solid tumor, hematologic malignancy, and dermatologic malignancy with cumulative incidences at 36 months of 6.1% (95% CI: 3.1%-10%), 4.5% (95% CI: 2.1%-8.1%) and 4.2% (95% CI: 2.1%-7.5%) respectively. Notably, no cases of T cell malignancies were observed. In univariable analysis, increasing age was associated with higher risk for subsequent malignancy. While the overall benefits of CAR T products continue to outweigh their potential risks, more studies and longer follow ups are needed to further demonstrate the risks, patterns, and molecular pathways that lead to the development of subsequent malignancies.

Low Levels of Natural Killer Cell in Newly Diagnosed Myelodysplastic Syndromes Patients May Confer Poor Prognosis: A Retrospective Cohort Study.

Background: Immune imbalance appears to have a critical role in tumor growth according to emerging research. Peripheral lymphocyte subsets are considered to reflect the systemic immune response and clinical prognosis. The prognostic value of lymphocyte subpopulations in myelodysplastic syndrome (MDS) patients remains unclear. Methods: A total of 94 MDS patients were enrolled for the study. X-tile software was performed to determine the prognostic significance of various lymphocyte subpopulations, CD3, CD4, CD8, CD4/CD8 ratio, natural killer cell (NK) and CD19. Among them, the appropriate threshold of NK percent could be found only. Patients were divided into the high NK percent group and the low NK percent group. The prognostic significance was determined by univariate and multivariate Cox hazard models. Results: MDS patients with lower NK level had significantly shorter overall survival (OS). Based on univariate analysis, male gender (P = 0.030), lower HB (<10 g/dl, P = 0.029), higher BM blast (>5%, P < 0.0001), higher-risk IPSS-R cytogenetic (P = 0.032) and lower NK percent (P < 0.0001) were significantly associated with shorter OS. Multivariate Cox proportional hazards regression analysis indicated that low NK was also independent adverse prognostic factor for OS in MDS. Conclusion: Decreased NK level predicts poor prognosis independent of the IPSS-R and provide a novel evaluation factor for MDS patients.

Abstracts of the Cell Therapy Transplant Canada 2023 Annual Conference.

On behalf of Cell Therapy Transplant Canada (CTTC), we are pleased to present the Abstracts of the CTTC 2023 Annual Conference. The conference was held in-person, 31 May-2 June 2023, in Halifax, Nova Scotia at the Westin Nova Scotian hotel. Poster authors presented their work during a lively and engaging welcome reception on Thursday, 1 June, and oral abstract authors were featured during the oral abstract session in the afternoon of Friday, 2 June 2023. Twenty-three (23) abstracts were selected for presentation as posters and four (4) as oral presentations. Abstracts were submitted within four categories: (1) Basic/Translational Sciences, (2) Clinical Trials/Observations, (3) Laboratory/Quality, and (4) Pharmacy/Nursing/Other Transplant Support. The top four (4) oral abstracts and top four (4) poster abstracts were selected to receive an award. All of these were marked as "Award Recipient" within the relevant category. We congratulate all the presenters on their research and contributions to the field.

HALP score as a novel prognostic factor for patients with myelodysplastic syndromes.

Myelodysplastic syndrome (MDS) is a heterogeneous spectrum of clonal hematopoietic disorders with varying degrees of cytopenia and morphologic dysplasia. The hemoglobin, albumin, lymphocyte, and platelet (HALP) score is a prognostic marker in several types of malignant tumors. Prognostic value of HALP score remains unclear for MDS. To determine the prognostic value of baseline HALP score in MDS. We retrospectively analyzed data from 130 newly diagnosed MDS patients evaluated and classified under HALP score. By the receiver operating characteristic (ROC) analysis, the optimal cut-off value of HALP was > 67.5 in predicting mortality. Patients were divided into two groups: with low and high HALP scores, and the characteristics were compared between both groups. Patients' median age was 68 (19-84) years, and 79 (60.8%) were male. Higher HALP score was detected in MDS patients with intermediate-risk under IPSS score, and at high and very high risks under IPSS-R score, and those receiving azacitidine (AZA) treatment. The survival rates of those with a HALP score > 67.5 were significantly lower than those with low HALP score at 17.77 ± 3.98 (median ± SE) (p < 0.001). The 3-, 5- and 10-years survival rates of individuals with HALP scores > 67.5 were found as 25, 18, and 11%, respectively. Median overall survival (OS) was also determined as 33.10 (95% CI 16.34-49.88) months by the Kaplan-Meier method. HALP score has shown an ability to be a useful prognostic biomarker in various cancers, including MDS. The meaningful cut-off value of HALP is disease-specific and largely study-specific. High HALP score is associated with unfavorable clinicopathological characteristics. Also, it may be useful in predicting OS and mortality of MDS.

Severe B12 Deficiency Causing a Maturation Defect Mimicking Myelodysplastic Syndrome With Excess Blasts.

Vitamin B12 deficiency is a common condition that is often asymptomatic, though in severe cases may cause megaloblastic anemia and even neurologic symptoms. Occasionally, the clinical presentation can include pancytopenia and thus mimic a more concerning myelodysplastic syndrome (MDS) until corrected by B12 supplementation. In this unusual case, we present a patient with B12 deficiency who presents with severe macrocytic anemia, neutropenia, lymphocytosis, and a bone marrow morphology consistent with MDS.

Clinicians' Perspectives on the Telehealth Serious Illness Care Program for Older Adults With Myeloid Malignancies: Single-Arm Pilot Study.

BACKGROUND: Serious illness conversations may help patients avoid unwanted treatments. We previously piloted the telehealth Serious Illness Care Program (SICP) for older adults with acute myeloid leukemia and myelodysplastic syndrome. OBJECTIVE: In this study, we aimed to understand the experience of the telehealth SICP from the clinician's perspective. METHODS: We studied 10 clinicians who delivered the telehealth SICP to 20 older adults with acute myeloid leukemia or myelodysplastic syndrome. Quantitative outcomes included confidence and acceptability. Confidence was measured using a 22-item survey (range 1-7; a higher score is better). Acceptability was measured using an 11-item survey (5-point Likert scale). Hypothesis testing was performed at α=.10 (2-tailed) due to the pilot nature and small sample size. Clinicians participated in audio-recorded qualitative interviews at the end of the study to discuss their experience. RESULTS: A total of 8 clinicians completed the confidence measure and 7 clinicians completed the acceptability measure. We found a statistically significant increase in overall confidence (mean increase of 0.5, SD 0.6; P=.03). The largest increase in confidence was in helping families with reconciliation and goodbye (mean 1.4, SD 1.5; P=.04). The majority of clinicians agreed that the format was simple (6/7, 86%) and easy to use (6/7, 86%). Clinicians felt that the telehealth SICP was effective in understanding their patients' values about end-of-life care (7/7, 100%). A total of three qualitative themes emerged: (1) the telehealth SICP deepened relationships and renewed trust; (2) each telehealth SICP visit felt unique and personal in a positive way; and (3) uninterrupted, unrushed time optimized the visit experience. CONCLUSIONS: The telehealth SICP increased confidence in having serious illness conversations while deepening patient-clinician relationships. TRIAL REGISTRATION: ClinicalTrials.gov NCT04745676; https://www.clinicaltrials.gov/study/NCT04745676.

[Effect of TP53 Allelic State on Clinical Performance and Prognosis of Patients with Myelodysplastic Syndrome].

OBJECTIVE: To investigate the clinical significance of TP53 allelic state in patients with myelodysplastic syndromes (MDS). METHODS: The clinical data of 858 MDS patients who underwent second-generation sequencing (NGS) testing in the First Affiliated Hospital of Soochow University from January 2019 to December 2021 were retrospectively analyzed. RESULTS: The median age of the patients was 52 years old, and median follow-up time was 23.8 (0.4-109.6) months. Four hundred and one patients (46.7%) had at least one chromosomal abnormality, including 106 complex karyotypes and 78 monosomal karyotypes. A total of 103 cases of TP53 mutations were identified, with a mutation rate of 12%. Compared with TP53 wild-type, various types of chromosomal abnormalities were significantly more common in patients with TP53 mutations (all P < 0.001). Patients with TP53 mutations had lower hemoglobin levels, lower platelet counts and higher percentage of bone marrow primitive cell compared with TP53 wild type (all P < 0.05), and significantly shorter overall survival (OS). Among 97 evaluable patients, 33 cases (34%) were mono-allelic TP53 mutation, while 64 cases were bi-allelic TP53 mutation. Patients in bi-allelic TP53 mutation subgroup had a higher proportion of chromosomal abnormalities and a lower number of co-mutations compared with mono-allelic TP53 mutation. The median OS was 33.6 months in patients with mono-allelic state and only 11.4 months in patients with bi-allelic state (HR=2.138, 95%CI : 1.053-4.343, P >0.05). Median OS was not reached in TP53 wild-type patients, and there was a significant difference in OS among TP53 wild-type, mono-allelic and bi-allelic TP53 mutation patients (P < 0.001). Multivariable Cox regression analysis showed that bi-allelic TP53 was an independent predictor of poor outcomes (HR=2.808, 95%CI : 1.487-5.003, P =0.001), while mono-allelic TP53 mutation and wild-type TP53 were not. CONCLUSION: Patients with TP53 mutations have a poor prognosis, and bi-allelic TP53 mutations have a worse prognosis compared with mono-allelic TP53 mutations and independently affect the prognosis of MDS patients.

VEXAS syndrome: A 2-case series report.

VEXAS syndrome is a rare entity secondary to UBA1 gene mutations, located on the X chromosome. This mutation generates, as a consequence, a characteristic vacuolation on haematopoietic stem-cells. It is characterized by multiple autoinflammatory and haematologic manifestations, which respond and end up being dependent on corticosteroid treatment. In this publication we present a 2-case series diagnosed at our hospital and make a brief literature review of the published evidence so far.

Inflamma-miRs Profile in Myelodysplastic Syndrome Patients.

Etiological factors involved in myelodysplastic syndrome (MDS) include immunologic, oxidative stress and inflammatory factors, among others, and these are targets for microRNAs (miRNs). Here, we evaluated whether some miRNs may affect tumor development comparing untreated and 5-azacitidine (5-AZA) MDS-treated patients. Peripheral blood samples were collected from 20 controls and 24 MDS patients, and selected miRNs related to redox balance and inflammation (inflamma-miRs), including miR-18a, miR-21, miR-34a and miR-146a, were isolated and measured by quantitative real-time polymerase chain reaction (qRTPCR). A differential expression profile of miRNs was detected in untreated MDS patients and the 5-AZA group. Inflammation increases miRNs and, specifically, miR-18a, miR-21 and miR-34a were significantly overexpressed in untreated MDS, compared to controls. However, we did not observe any miRN profile alteration during the progression of the disease. On the other hand, 5-AZA treatment tends to restore miRN expression levels. Relating to prognostic risk factors, high-risk MDS groups (high Revised International Prognostic Scoring System (IPSS-R), high cytogenetic risk, high molecular risk (HMR) mutations) tended to be related with higher expression levels of miR-18a and miR-34a. Higher miRN expression is correlated with lower glutathione peroxidase activity, while they are related with a higher profile of pro-inflammatory cytokines (IL-2, IL-6, IL-8, TNF-α). Although our study was limited by the low number of MDS patients included, we identified miRN deregulation involved in MDS development that could regulate redox sensors and inflammatory responses. Finally, 5-AZA treatment is related with lower miRN expression levels in MDS patients.

Donor Lymphocyte Infusion (DLI) post allogeneic stem cell transplant (allo-SCT) in Acute Myeloid Leukemia (AML) and High-Grade Myelodysplastic Syndrome (MDS). A longitudinal retrospective study using peripheral blood (PB) CD34+ and CD3+ donor chimerism (DC) monitoring.

INTRODUCTION: This longitudinal study was based on the outcomes of Donor Lymphocyte Infusion (DLI) for falling peripheral blood (PB) CD34+ and CD3+ donor chimerism (DC). METHODS: From 2012 to 2018, data was collected from the BMT database and electronic medical records (EMR). The primary objective was to compare the indication for DLI based on falling PB CD34+ or CD3+ DC in patients post allo-SCT for AML and MDS and their overall survival (OS). RESULTS: 18/70 patients met the inclusion criteria. Indications for DLI were i) falling PB CD34+ DC ≤ 80 % with morphological relapse, ii) falling PB CD34+ DC ≤ 80 % without morphological relapse and iii) falling PB CD3+ DC ≤ 80 % without falling PB CD34+ DC. Log rank analysis showed falling PB CD34+ DC and morphological relapse had significantly lower OS. Linear regression demonstrated better OS post DLI if there was PB CD34+ and CD3+ chimerism response at 30 days (p = 0.029), GVHD (p = 0.032) and tapering immunosuppression at the time of falling DC (p = 0.042). CONCLUSION: DLI for PB CD34+ DC values ≤ 80 % and morphological relapse had the lowest OS. In this study, full DC was achieved after DLI even with a PB CD3+DC value as low as 13 %, provided the PB CD34+ DC remained > 80 %. Further research is vital in CD34+ DC as a biomarker for disease relapse and loss of engraftment.

Impact of Early Cytomegalovirus Reactivation After Allogeneic Hematopoietic Stem Cell Transplantation on Relapse in Patients With Myelodysplastic Syndrome: A Nationwide Retrospective Study From Adult Myelodysplastic Syndrome Working Group of the JSTCT.

Cytomegalovirus (CMV) reactivation is a prominent complication associated with adverse outcomes in allogeneic hematopoietic stem cell transplantation (HSCT). However, CMV reactivation after allogeneic HSCT may be associated with a lower incidence of relapse in some hematological malignancies. This study analyzed the Japanese registry data from 1082 patients with myelodysplastic syndrome (MDS) who underwent their first allogeneic HSCT and survived for 100 days after transplantation without graft failure or disease relapse to investigate this association. Patients who received cord blood transplants, demonstrated in vivo T cell depletion, underwent prophylactic anti-CMV treatment, or diagnosed with secondary MDS were excluded. CMV reactivation measured by pp65 antigenemia within 100 days after allogeneic HSCT was observed in 57.5% of patients, with a median time of 46 days from transplant. The 5-yr overall survival and cumulative incidence of relapse (CIR) in the cohort were 60.5% and 15.6%, respectively. The 5-yr CIR showed no significant difference between patients with and without CMV reactivation (14.4% versus 17.2%; P = .185). Interestingly, CMV reactivation within 100 days was significantly associated with a lower 5-yr CIR (7.6% versus 16.4%; P = .002) in patients with <5% myeloblasts in the bone marrow (BM) just before HSCT. Furthermore, this relevancy confirmed even when excluding patients with Grade II to IV acute GVHD (Hazard ratio: 0.38; 95% confidential intervals: 0.18-0.801; P = .011). Our findings indicate a correlation between early CMV reactivation and MDS relapse, based on the proportion of myeloblasts in the BM. These results may contribute to the development of effective CMV prophylaxis post-HSCT.

Multiplex imaging reveals spatially resolved DNA-damage response neighborhoods in TP53-mutated myelodysplastic neoplasms.

While increased DNA damage is a well-described feature of myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), it is unclear whether all lineages and all regions of the marrow are homogeneously affected. In this study, we performed immunohistochemistry on formalin-fixed, paraffin-embedded whole-section bone marrow biopsies using a well-established antibody to detect pH2A.X (phosphorylated histone variant H2A.X) that recognizes DNA double-strand breaks. Focusing on TP53-mutated and complex karyotype MDS/AML, we find a greater pH2A.X+ DNA damage burden compared to TP53 wild-type neoplastic cases and non-neoplastic controls. To understand how double-strand breaks vary between lineages and spatially in TP53-mutated specimens, we applied a low-multiplex immunofluorescence staining and spatial analysis protocol to visualize pH2A.X+ cells with p53 protein staining and lineage markers. pH2A.X marked predominantly mid- to late-stage erythroids, whereas early erythroids and CD34+ blasts were relatively spared. In a prototypical example, these pH2A.X+ erythroids were organized locally as distinct colonies, and each colony displayed pH2A.X+ puncta at a synchronous level. This highly coordinated immunophenotypic expression was also seen for p53 protein staining and among presumed early myeloid colonies. Neighborhood clustering analysis showed distinct marrow regions differentially enriched in pH2A.X+/p53+ erythroid or myeloid colonies, indicating spatial heterogeneity of DNA-damage response and p53 protein expression. The lineage and architectural context within which DNA damage phenotype and oncogenic protein are expressed is relevant to current therapeutic developments that leverage macrophage phagocytosis to remove leukemic cells in part due to irreparable DNA damage. © 2024 The Pathological Society of Great Britain and Ireland.

A Brief Overview of the Molecular Landscape of Myelodysplastic Neoplasms.

Myelodysplastic neoplasm (MDS) is a heterogeneous group of clonal hematological disorders that originate from the hematopoietic and progenitor cells and present with cytopenias and morphologic dysplasia with a propensity to progress to bone marrow failure or acute myeloid leukemia (AML). Genetic evolution plays a critical role in the pathogenesis, progression, and clinical outcomes of MDS. This process involves the acquisition of genetic mutations in stem cells that confer a selective growth advantage, leading to clonal expansion and the eventual development of MDS. With the advent of next-generation sequencing (NGS) assays, an increasing number of molecular aberrations have been discovered in recent years. The knowledge of molecular events in MDS has led to an improved understanding of the disease process, including the evolution of the disease and prognosis, and has paved the way for targeted therapy. The 2022 World Health Organization (WHO) Classification and the International Consensus Classification (ICC) have incorporated the molecular signature into the classification system for MDS. In addition, specific germline mutations are associated with MDS development, especially in pediatrics and young adults. This article reviews the genetic abnormalities of MDS in adults with a brief review of germline predisposition syndromes.