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Cyclin D1-negative mantle cell lymphoma (MCL) is regarded as a B-cell neoplasm that has morphologic and immunophenotypic findings indistinguishable from typical MCL. These neoplasms lack cyclin D1 overexpression by immunohistochemistry and t(11;14)(q13;q32)/ IGH::CCND1. Since cyclin D1-negative MCL was first recognized by gene expression profiling in 2003, there has been diagnostic confusion regarding this entity, mostly attributable to a lack of diagnostic tools to recognize these neoplasms in most clinical laboratories. Accumulated data show that most cyclin D1-negative MCL cases harbor CCND2 or CCND3 translocation with a variety of gene partners. In this review, the concept of cyclin D1-negative MCL is discussed in chronological order to further our understanding of this entity. We then discuss currently available diagnostic approaches and we conclude with future directions. We also suggest that the more specific terms CCND2-rearranged MCL or CCND3-rearranged MCL be used for neoplasms in which the rearranged gene is known, and that we reserve the term cyclin D1-negative MCL for neoplasms in which the rearranged gene in unknown., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflicts of interest directly related to the topic of this article., (Copyright © 2024. Published by Elsevier Inc.)

Background: KIT p.D816 mutation is strongly associated with systemic mastocytosis (SM). Next-generation sequencing (NGS) is now routinely performed in almost all bone marrow sample and KIT mutations are detected from patients who are not known or suspected to have SM. Therefore, we wanted to assess if KIT mutations in this patient population are associated with unsuspected SM., Methods: We searched NGS result in our institution with positive result for KIT mutation from patients with known/suspected myeloid neoplasms. Patients with previously documented history of systemic mastocytosis were excluded. Bone marrow biopsies from patients with KIT mutation were assessed with immunohistochemical stains for CD117 and mast cell tryptase (MST)., Results: Bone marrow biopsies were assessed with immunohistochemical stains for CD117 and mast cell tryptase (n = 49). Most patients had acute myeloid leukemia (AML, n = 38) or chronic myelomonocytic leukemia (CMML, n = 6). Immunohistochemical stains for CD117 and tryptase were performed in all 49 patients. A total of 4 patients (8.2%) showed mast cell nodules where spindled shaped mast cells were present, meeting the WHO criteria for SM. All four patients had KIT p.D816V mutation and had high mutant allelic frequency (∼ 50%) except one patient (1%)., Conclusion: We discovered approximately 8% of patients who had myeloid neoplasms with unexpected KIT mutations fulfilled the diagnostic criteria for systemic mastocytosis after additional immunohistochemical studies. Our data support that application of additional immunohistochemical studies is recommended to identify underrecognized SM when KIT mutations are found by molecular assays., Competing Interests: Disclosure CYO has received research funding from Blueprint Medicines., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

We present 2 diagnostically challenging cases of pediatric/adolescent relapsed/refractory aggressive mature B-cell non-Hodgkin lymphoma (B-NHL) within the spectrum of Burkitt lymphoma and diffuse large B-cell lymphoma and illustrate the different therapeutic regimens that are employed for pediatric and adult cancer centers. Both cases displayed varying-sized lymphoma cells with occasional single prominent nucleoli and heterogeneous BCL2 expression. Cytogenetics revealed complex karyotypes with t(8:14)(q24.2;q32) and IGH::MYC rearrangement by FISH. Next generation sequencing revealed deleterious TP53 and MYC mutations. We concluded that both could be diagnosed as "DLBCL-NOS with MYC rearrangement" using the current pathologic classifications, 2022 International Consensus Classification (ICC) and World Health Organization Classifications of Haematolymphoid Tumors (WHO-HAEM5). This report illustrates diagnostic challenges and treatment dilemmas that may be encountered, particularly for adolescent and young adults (AYA)., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Context.—: Flow cytometry immunophenotypic analysis plays an important role in the diagnosis, classification, and disease monitoring of hematologic neoplasms. The interpretation of flow cytometry testing can be challenging., Objective.—: To explore ways to improve diagnostic accuracy and in turn enhance the quality of patient care., Design.—: A flow cytometry quality assurance (QA) program was developed. Cases from various complex flow cytometry panels were randomly selected and cross-reviewed. The outcomes of the QA review were categorized into 3 groups: complete agreement, minor discrepancy, and major discrepancy. Each discrepancy underwent a process of documentation, discussion, and resolution. Here we summarize our 3 years of experience with this program., Results.—: In total, 6166 cases were evaluated; 6028 cases (97.7%) showed complete concordance, 120 cases (2.0%) showed minor discrepancies, and 18 cases (0.3%) showed major discrepancies. Among the top 5 panels evaluated, the panel evaluating mature T-cell abnormalities showed the highest rate of discrepancy, whereas the panel for evaluation of myelodysplastic syndromes showed the lowest discrepancy rate. When analyzing the trends of concordance and discrepancy over time, we observed a statistically significant decrease in discrepancy rate over time, from 4% at the beginning of the 6-month period to 1.5% in the final 6-month period., Conclusions.—: The overall concordance rate was 97.7%. The remaining 2.3% of cases showed discrepancies that required a correction, underscoring the value and necessity of having a QA program. The overall discrepancy rates exhibited a gradual decline over time, indicative of the positive impact of the QA program on enhancing diagnostic competency and accuracy over time., Competing Interests: The authors have no relevant financial interest in the products or companies described in this article., (© 2024 College of American Pathologists.)

Objectives: Flow cytometric immunophenotyping (FCI) is a fast and sensitive method for characterizing hematolymphoid neoplasms. It is not widely used in the workup of systemic mastocytosis (SM), in part because of the technical challenges and in part because the utility of FCI in assessing mast cells is not well understood. The objectives of this study were to assess the diagnostic utility of FCI in establishing a diagnosis of SM and distinguishing SM from nonneoplastic mast cells and to examine the immunophenotypic findings among SM subtypes., Methods: We performed FCI on bone marrow samples suspicious for SM using a panel consisting of CD2, CD25, CD30, CD45, CD117, and HLA-DR., Results: The cohort included 88 SM cases: 67 without an associated hematologic neoplasm (AHN) (PureSM) and 21 with an AHN (SM-AHN). We also assessed 40 normal/reactive controls. Overall, FCI was adequate for interpretation in 87 of 88 (99%) cases and detected at least 1 immunophenotypic aberrancy in 100% of SM cases. CD2, CD25, and CD30 were positive in 78%, 98%, and 90% of SM cases vs 0%, 13%, and 13% of cases with normal/reactive mast cells (P < .0001 for all). Two or 3 abnormalities were observed in 92% of SM cases but not in normal/reactive mast cells. Among SM cases, SM-AHN showed statistically significant less CD2 (38% vs 91%, P < .0001) and less co-expression of all 3 aberrant markers (CD2, CD25, and CD30 positive in 38% vs 86% of cases; P < .0001) than PureSM. Immunohistochemical analysis showed consistently weaker or focal expression of CD2, CD25, and CD30 than FCI, with CD2 and CD30 being falsely negative in 40% and 50% cases, respectively. A KIT D816V mutation was detected in 67% of PureSM cases and 76% of SM-AHN cases., Conclusions: Flow cytometric immunophenotyping is a quick, sensitive, high-yield tool for evaluating the immunophenotype of mast cells. An abnormal FCI finding should prompt careful histologic evaluation and sensitive KIT D816V mutation testing to address the possibility of SM. CD2, CD25, and CD30 are important markers for the detection of immunophenotypic aberrancy of mast cells, and their frequencies of aberrancy differ across SM subtypes., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Breast implant-associated anaplastic large cell lymphoma has been recognized as a distinct entity in the World Health Organization classification of hematolymphoid neoplasms. These neoplasms are causally related to textured implants that were used worldwide until recently. Consequently, there is an increased demand for processing periprosthetic capsules, adding new challenges for surgeons, clinicians, and pathologists. In the literature, the focus has been on breast implant-associated anaplastic large cell lymphoma; however, benign complications related to the placement of breast implants occur in up to 20% to 30% of patients. Imaging studies are helpful in assessing patients with breast implants for evidence of implant rupture, changes in tissues surrounding the implants, or regional lymphadenopathy related to breast implants, but pathologic examination is often required. In this review, we couple our experience with a review of the literature to describe a range of benign lesions associated with breast implants that can be associated with different clinical presentations or pathogenesis and that may require different diagnostic approaches. We illustrate the spectrum of the most common of these benign disorders, highlighting their clinical, imaging, gross, and microscopic features. Finally, we propose a systematic approach for the diagnosis and handling of breast implant specimens in general., Competing Interests: Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Enhancer of zeste homolog 2 (EZH2) expression is found in about 40% of mantle cell lymphoma (MCL) patients, which is associated with aggressive histology, high Ki-67 proliferation rate, p53 mutant pattern and inferior overall survival (OS). We conducted 11-gene (ATM, BIRC3, CCND1, KMT2C, KMT2D, NOTCH1, NOTCH2, RB1, TP53, TRAF2 and UBR5) next generation sequencing panel to shed more light on MCL with EZH2 expression (EZH2+ MCL). EZH2+ MCL more frequently harbor TP53 mutation compared to EZH2(-) MCL (41.2% vs. 19.1%, respectively, p = 0.045). TP53 mutation and EZH2 expression demonstrated overlapping features including aggressive histology, high Ki-67 proliferation rate and p53 mutant pattern by immunohistochemistry. Comparative analysis disclosed that EZH2 expression correlates with high Ki-67 proliferation rate irrespective of TP53 mutation. Aggressive histology is associated with EZH2 expression or TP53 mutation, possibly via independent mechanisms. p53 mutant pattern is due to TP53 mutation. MCL patients with EZH2 expression or TP53 mutation show inferior outcome and when both are present, patients have dismal outcome., Competing Interests: Declaration of competing interest The authors declare that they have no conflicts of interest directly related to the topic of this article., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Optical genome mapping (OGM) is a new DNA-based technology which provides comprehensive examination of the entire genome. We report two patients who presented with splenomegaly and leukocytosis with lymphocytosis including villous lymphocytes. Neither patient had lymphadenopathy. Bone marrow evaluation showed involvement by small B-cell lymphoma in a sinusoidal and interstitial distribution, and immunophenotypic analysis showed that the neoplastic cells were positive for B-cell markers and cyclin D1 but were negative for SOX11 and CD5. Initially, the clinicopathologic features in both patients were thought to be suspicious for hairy cell leukemia variant or splenic marginal zone lymphoma. However, OGM detected CCND1 rearrangement: t(2;11)/IGK::CCND1 in one case and t(11;14)/IGH::CCND1 in the other case. These cases illustrate the valuable role OGM can play in establishing the diagnosis of MCL. Case 1 also contributes to the paucity of literature on the rare occurrence of IGK::CCND1 in MCL., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Burkitt lymphoma (BL) is a mature B-cell neoplasm arising from germinal center B-cells. There are three epidemiological variants of which the sporadic variant is most prevalent in developed countries representing 1-2 % of all lymphomas in adults. Patients usually present with bulky abdominal masses and ~ 30 % have bone marrow involvement. BL is characterized by a germinal center B-cell immunophenotype and usually has a simple karyotype. Here we report an unusual case of sporadic BL in a 44-year-old man and we use this case to review sporadic BL in adults. The patient presented with a cecal mass and bone marrow involvement. Biopsy of the cecal mass and bone marrow evaluation showed infiltration by intermediate-size lymphoma cells positive for monotypic kappa, CD10, CD19, CD20, CD22, CD38 bright, CD43, CD45, Bcl6 and ROR1, and negative for CD11c, CD23, CD30, CD44, CD200 and Bcl2. As expected, the lymphoma cells were strongly positive for MYC and Ki-67 showed a proliferation rate of nearly 100 %, but the cells were also positive for SOX11 and cytoplasmic LEF1. Conventional chromosomal analysis revealed t(8;14) as part of a complex karyotype. Based on our literature review, and is shown in this case, sporadic BL in adults shows some differences with the classic description of BL in children. We also discuss the differential diagnosis of BL., Competing Interests: Declaration of competing interest None., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Acute myeloid leukemia (AML) minimal/measurable residual disease (MRD) by multicolor flow cytometry is a complex laboratory developed test (LDT), challenging for implementation. We share our experience in the validation of a 12-color AML MRD flow cytometry assay to meet stringent regulatory requirements., Methods: We worked under the guidelines of the CLSI HL62 publication, illustrated the details of the validation process that was tailored to uniqueness of AML MRD, and tested its clinical validity in 61 patients. The "trueness" was determined by correlating with concurrent molecular genetic testing and follow-up bone marrow examinations., Results: Under assay specificity, we shared the details of panel design, analysis, and criteria for interpretation and reporting. The assay accuracy was assessed by testing known positive and negative samples and correlating with molecular genetic testing and follow-up bone marrow examination. The limit of detection (LOD) and limit of quantification (LOQ) were validated to a level between 0.01% and 0.1%, varied from the leukemia-associated immunophenotypes (LAIP) and the numbers of events obtained for analysis. Assay linearity, precision and carry over studies all met acceptable criteria. In the clinical validity test, the concordance was 93%, specificity 98% and sensitivity 83%. The most challenging aspects of the assay were the discrimination of pre-leukemic cells (persistent clonal hematopoiesis) or underlying myelodysplastic clones from AML MRD with immunophenotypic switch or subclone selection., Conclusion: The validation met all criteria and obtained FDA IDE (investigational device exemption) approval. This study provides ample technical and professional details in setting up the AML MRD flow cytometry assay and illustrates through the example of the "fit for purpose" validation process. We also highlight the need for further characterization of abnormal blasts bearing the potential for AML relapse., (© 2023 International Clinical Cytometry Society.)

Patients with mantle cell lymphoma (MCL), an incurable B-cell malignancy, benefit from accurate pretreatment disease stratification. We curated an extensive database of 862 patients diagnosed between 2014 and 2022. A machine learning (ML) gradient-boosted model incorporated baseline features from clinicopathologic, cytogenetic, and genomic data with high predictive power discriminating between patients with indolent or responsive MCL and those with aggressive disease (AUC ROC = 0.83). In addition, we utilized the gradient-boosted framework as a robust feature selection method for multivariate logistic and survival modeling. The best ML models incorporated features from clinical and genomic data types highlighting the need for correlative molecular studies in precision oncology. As proof of concept, we launched our most accurate and practical models using an application interface, which has potential for clinical implementation. We designated the 20-feature ML model-based index the "integrative MIPI" or iMIPI and a similar 10-feature ML index the "integrative simplified MIPI" or iMIPI-s. The top 10 baseline prognostic features represented in the iMIPI-s are: lactase dehydrogenase (LDH), Ki-67%, platelet count, bone marrow involvement percentage, hemoglobin levels, the total number of observed somatic mutations, TP53 mutational status, Eastern Cooperative Oncology Group performance level, beta-2 microglobulin, and morphology. Our findings emphasize that prognostic applications and indices should include molecular features, especially TP53 mutational status. This work demonstrates the clinical utility of complex ML models and provides further evidence for existing prognostic markers in MCL., Significance: Our model is the first to integrate a dynamic algorithm with multiple clinical and molecular features, allowing for accurate predictions of MCL disease outcomes in a large patient cohort., (© 2023 The Authors; Published by the American Association for Cancer Research.)

The blastoid (B) and pleomorphic (P) variants of mantle cell lymphoma (MCL) are associated with aggressive clinical behavior. In this study, we collected 102 cases of B-MCL and P-MCL from untreated patients. We reviewed clinical data, analyzed morphologic features using an image analysis tool (ImageJ) and we assessed mutational and gene expression profiles. The chromatin pattern of lymphoma cells was assessed quantitatively by the pixel value. Cases of B-MCL showed a greater median pixel value with lower variation compared with P-MCL, indicating a homogeneously euchromatin-rich pattern in B-MCL. In addition, the Feret diameter of the nuclei was significantly smaller (median 6.92 vs. 8.49 µm per nucleus, P <0.001) and had a lesser degree of variation in B-MCL compared with P-MCL, indicating that B-MCL cells have smaller cells with a more monomorphic appearance. B-MCL showed a significantly higher median Ki-67 proliferation rate (60% vs. 40%, P =0.003), and affected patients had poorer overall survival compared with those with P-MCL (median overall survival: 3.1 vs. 8.8 y, respectively, P =0.038). NOTCH1 mutation was significantly more frequent in B-MCL compared with P-MCL (33% and 0%, respectively, P =0.004). Gene expression profiling showed 14 genes overexpressed in B-MCL cases and gene set enrichment assay for the overexpressed genes showed significant enrichment in the cell cycle and mitotic transition pathways. We also report a subset of MCL cases that has blastoid chromatin but a higher degree of pleomorphism in nuclear size and shape, designated here as hybrid MCL. Hybrid MCL cases had a similar Ki-67 proliferation rate, mutation profile, and clinical outcome to B-MCL and distinct from P-MCL. In summary, these data suggest biological differences between B-MCL and P-MCL cases justifying their separate designation when possible., Competing Interests: Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Chimeric antigen receptor (CAR) T-cells anti-CD30 is an innovative therapeutic option that has been used to treat cases of refractory/relapsed (R/R) classic Hodgkin lymphoma (CHL). Limited data are available regarding the CD30 expression status of patients who relapsed after this therapy. This is the first study to show decreased CD30 expression in R/R CHL in patients (n = 5) who underwent CAR T-cell therapy in our institution between 2018 and 2022. Although conventional immunohistochemical assays showed decreased CD30 expression in neoplastic cells in all cases (8/8) the tyramide amplification assay and RNAScope in situ hybridisation detected CD30 expression at different levels in 100% (n = 8/8) and 75% (n = 3/4), respectively. Hence, our findings document that certain levels of CD30 expression are retained by the neoplastic cells. This is not only of biological interest but also diagnostically important, as detection of CD30 is an essential factor in establishing a diagnosis of CHL., (© 2023 John Wiley & Sons Ltd.)

Background: /purpose: Dental pulp plays an important role in the maintenance of tooth homeostasis and repair. The aging of dental pulp affects the functional life of the tooth owing to the senescence of dental pulp cells. Toll-like receptor 4 (TLR4) is involved in regulating cellular senescence in dental pulp. We have recently demonstrated that visfatin induces the senescence of human dental pulp cells (hDPCs). Here, we explored the association of TLR4 with visfatin signaling in cellular senescence in hDPCs., Materials and Methods: mRNA levels were determined using reverse transcription polymerase chain reaction (PCR) and quantitative real time-PCR. Protein levels were determined using immunofluorescence staining and Western blot analysis. Gene silencing was performed using small interfering RNA. The degree of cellular senescence was measured by senescence-associated-β-galactosidase (SA-β-gal) staining. Oxidative stress was determined by measurement of NADP/NADPH levels and intracellular reactive oxygen species (ROS) levels., Results: Neutralizing anti-TLR4 antibodies or TLR4 inhibitor markedly blocked visfatin-induced hDPCs senescence, as revealed by an increase in the number of SA-β-gal-positive hDPCs and upregulation of p21 and p53 proteins. Moreover, visfatin-induced senescence was associated with excessive ROS production; NADPH consumption; telomere DNA damage induction; interleukin (IL)-1β, IL-6, IL-8, cyclooxygenase-2, and tumor necrosis factor-α upregulation; and nuclear factor-κB and mitogen-activated protein kinase activation. All of these alterations were attenuated by TLR4 blockade., Conclusion: Our findings indicate that TLR4 plays an important role in visfatin-induced senescence of hDPCs and suggest that the visfatin/TLR4 signaling axis can be a novel therapeutic target for the treatment of inflammaging-related diseases, including pulpitis., Competing Interests: The authors declare that they have no conflicts of interest., (© 2022 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

Background: ETNK1 mutation has been suggested as a useful tool to support the diagnosis of atypical chronic myeloid leukemia. ETNK1 mutations, however, occur in other myeloid neoplasms., Methods: The authors assessed the clinicopathologic and molecular genetic features of 80 ETNK1-mutated myeloid neoplasms., Results: Thirty-seven neoplasms (46%) were classified as myelodysplastic syndrome, 17 (21%) were classified as myelodysplastic/myeloproliferative neoplasm, 14 (18%) were classified as acute myeloid leukemia, and 12 (15%) were classified as myeloproliferative neoplasm. ETNK1 mutations were detected at the first test in 96% of patients, suggesting that ETNK1 mutation is an early event in pathogenesis. ETNK1 mutations represented the dominant clone in 63% of patients and was persistently dominant in 93%. The variant allele frequencies were usually higher in acute myeloid leukemia and increased upon leukemic transformation. ETNK1 mutation was accompanied by coexisting mutations in all patients, with ASXL1 (50%), TET2 (25%), EZH2 (24%), RUNX1 (24%), and SRSF2 (24%) mutations being the most common. Neoplasms with ETNK1 mutations were associated with morphologic dysplasia, increased blasts, myelofibrosis, and noncomplex karyotypes. With a median follow-up of 16.5 months, 30 patients died, 44 had persistent disease, and four achieved complete remission after stem cell transplantation., Conclusions: ETNK1 mutation is present in various myeloid neoplasms, often as an early event and a dominant clone and always with concurrent mutations. It may play an important role in the pathogenesis and progression of myeloid neoplasms by causing DNA damage and inducing other mutations and genomic instability, and it may serve as a potential therapeutic target. ETNK1 mutation is not disease-specific and should be interpreted with caution to classify myeloid neoplasms., (© 2022 American Cancer Society.)

High-grade B-cell lymphoma, not otherwise specified (HGBL-NOS) is rare and data focused on these neoplasms is lacking. We studied the clinicopathologic and genetic features of 136 HGBL-NOS patients and compared them to patients with DLBCL/HGBL-DH (n = 224, defined by 5th Edition WHO) and DLBCL (n = 217). HGBL-NOS patients had clinical features similar to DLBCL/HGBL-DH patients. MYC rearrangement (MYC-R) was present in 43% of HGBL-NOS. With induction regimen similar to DLBCL/HGBL-DH patients, HGBL-NOS patients had a median overall survival (OS) of 28.9 months, similar to DLBCL/HGBL-DH (p = 0.48) but inferior to DLBCL patients (p = 0.03). R-EPOCH induction was associated with improved OS compared with R-CHOP. MYC-R, history of lymphoma, and high IPI were independent adverse prognostic factors in HGBL-NOS patients. Whole transcriptome profiling performed on a subset of HGBL-NOS cases showed a profile more similar to DLBCL/HGBL-DH than to DLBCL; 53% of HGBL-NOS had a DH-like signature (DH-like-Sig) and were enriched for MYC-R. DH-like-Sig+ HGBL-NOS patients had a poorer OS than DH-like-Sig-negative patients (p = 0.04). In conclusion, HGBL-NOS has clinicopathologic features and a gene expression profile more similar to DLBCL/HGBL-DH than to DLBCL. Cases of HGBL-NOS frequently carry MYC-R and have a DH-like-Sig+. R-EPOCH induction in HGBL-NOS appears associated with improved OS compared with standard R-CHOP., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

It has been reported that gene mutations in SF3B1 and PHF6 are mutually exclusive. However, this observation has never been rigorously assessed. We report the clinicopathologic and molecular genetic features of 21 cases of myeloid neoplasms with double mutations in SF3B1 and PHF6 , including 9 (43%) with myelodysplastic syndrome, 5 (24%) with acute myeloid leukemia, 4 (19%) with myeloproliferative neoplasms, and 3 (14%) with myelodysplastic/myeloproliferative neoplasms. Multilineage dysplasia with ring sideroblasts, increased blasts, and myelofibrosis are common morphologic findings. All cases but one had diploid or non-complex karyotypes. SF3B1 mutations were detected in the first analysis of all the patients. PHF6 mutations occurred either concurrently with SF3B1 mutations or in subsequent follow-up samples and are associated with disease progression and impending death in most cases. Most cases had co-mutations, the most common being ASXL1 , RUNX1 , TET2 , and NRAS . With a median follow-up of 39 months (range, 3-155), 17 (81%) patients died, 3 were in complete remission, and 1 had persistent myelodysplastic syndrome. The median overall survival was 51 months. In summary, concurrent mutations in SF3B1 and PHF6 are rare, but they do exist in a variety of myeloid neoplasms, with roles as early initiating events and in disease progression, respectively.

Myeloproliferative neoplasms (MPNs) are frequently associated with classic driver mutations involving JAK2, MPL or CALR. SRSF2 is among the most frequently mutated splicing genes in myeloid neoplasms and SRSF2 mutations are known to confer a poor prognosis in patients with MPNs. In this study, we sought to evaluate the clinicopathologic spectrum of myeloid neoplasms harboring concurrent MPN-driver mutations and SRSF2 mutations. The study cohort included 27 patients, 22 (82%) men and five (19%) women, with a median age of 71 years (range, 51-84). These patients presented commonly with organomegaly (n = 15; 56%), monocytosis (n = 13; 48%), morphologic dysplasia (n = 11; 41%), megakaryocytic hyperplasia and/or clustering (n = 10; 37%) and bone marrow fibrosis >MF-1 (17/22; 77%). About one third of patients either initially presented with acute myeloid leukemia (AML) or eventually progressed to AML. Eighteen (68%) patients had a dominant clone with SRSF2 mutation and nine (33%) patients had a dominant clone with a classic MPN-associated driver mutation. Our data suggest that the presence of an SRSF2 mutation preceding the acquisition of a MPN driver mutations is not a disease-defining alteration nor is it restricted to any specific disease entity within the spectrum of myeloid neoplasms. In summary, patients with myeloid neoplasms associated with concurrent SRSF2 and classic MPN driver mutations have clinical and morphologic features close to that of classic MPNs often with frequent dysplasia and monocytosis., (© 2022. The Author(s), under exclusive licence to United States & Canadian Academy of Pathology.)

EZH2 coding mutation (EZH2 MUT ), resulting in loss-of-function, is an independent predictor of overall survival in MDS. EZH2 function can be altered by other mechanisms including copy number changes, and mutations in other genes and non-coding regions of EZH2. Assessment of EZH2 protein can identify alterations of EZH2 function missed by mutation assessment alone. Precise evaluation of EZH2 function and gene-protein correlation in clinical MDS cohorts is important in the context of upcoming targeted therapies aimed to restore EZH2 function. In this study, we evaluated the clinicopathologic characteristics of newly diagnosed MDS patients with EZH2 MUT and correlated the findings with protein expression using immunohistochemistry. There were 40 (~6%) EZH2 MUT MDS [33 men, seven women; median age 74 years (range, 55-90)]. EZH2 mutations spanned the entire coding region. Majority had dominant EZH2 clone [median VAF, 30% (1-92)], frequently co-occurring with co-dominant TET2 (38%) and sub-clonal ASXL1 (55%) and RUNX1 (43%) mutations. EZH2 MUT MDS showed frequent loss-of-expression compared to EZH2 WT (69% vs. 27%, p = 0.001). Interestingly, NINE (23%) EZH2 WT MDS also showed loss-of-expression. EZH2 MUT and loss-of-expression significantly associated with male predominance and chr(7) loss. Further, only EZH2 loss-of-expression patients showed significantly lower platelet counts, a trend for higher BM blast% and R-IPSS scores. Over a 14-month median follow-up, both EZH2 MUT (p = 0.027) and loss-of-expression (p = 0.0063) correlated with poor survival, independent of R-IPSS, age and gender. When analyzed together, loss-of-expression showed a stronger correlation than mutation (p = 0.061 vs. p = 0.43). In conclusion, immunohistochemical assessment of EZH2 protein, alongside mutation, is important for prognostic workup of MDS., (© 2022. The Author(s), under exclusive licence to United States & Canadian Academy of Pathology.)

NOTCH1 is one of the most frequently mutated genes in chronic lymphocytic leukemia and has emerged as a marker of poor prognosis. In addition to coding NOTCH1 mutations involving exon 34, non-coding NOTCH1 mutations involving the 3' UTR have been described in a limited number of chronic lymphocytic leukemia (CLL) patients and were associated with adverse outcomes. In this study, 1574 CLL patients were assessed using targeted sequencing with a 29 gene panel and the results were correlated with prognostic characteristics. NOTCH1 mutations were detected in 252 (16%) patients, including both coding (220/252, 14%), non-coding (24/252, 1.5%) and a mixture of coding and non-coding (8/252, 0.5%) NOTCH1 mutations. NOTCH1 mutations were more commonly seen in patients with unmutated IGHV, ZAP70 positivity and CD38 positivity. Mixed NOTCH1 mutations were also more commonly seen in patients with unmutated IGHV and ZAP70. There was no association between mixed NOTCH1 mutations and CD38 expression in this cohort. The most common cytogenetic alteration detected in patients with coding and mixed NOTCH1 mutations was trisomy 12, whereas del13q was the most common cytogenetic alteration detected in patients with non-coding NOTCH1 mutation. The most common gene mutations co-occurring with coding NOTCH1 mutations were: TP53 (23.2%), SF3B1 (16.4%) and SPEN (10%). The most common gene mutations co-occurring with non-coding NOTCH1 mutations were: SF3B1 11(34.4%), ATM 4(12.5%) and TP53 4(12.5%). CLL patients with clonal coding and non-coding NOTCH1 mutations had a significantly shorter time-to-first treatment than patients with wild type NOTCH1 (4.3 vs 10.0 years and 0.9 vs 10.0 years respectively, p < 0.05). Similarly, CLL patients with subclonal coding NOTCH1 mutations had a significantly shorter time-to-first treatment than patients with wild type NOTCH1 (5.6 vs 10.0 years, p < 0.05). CLL patients with subclonal non-coding NOTCH1 mutations also had a shorter time-to-first treatment than patients with wild type NOTCH1 mutations, however, the difference was not significant (5.1 vs 10.0 years, p = 0.15). These data confirm that both coding and non-coding NOTCH1 mutations carry adverse prognostic impact and need to be included in sequencing assays performed for the prognostic workup of CLL patients., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The role of WT1 protein in hematopoiesis and leukemogenesisis incompletely elucidated. WT1 overexpression is common in acute myeloid leukemia (AML); however, WT1 mutations occur in only about 10% of cases, with increasing incidence in the setting of relapse. In this study, we investigated the clinical and molecular characteristics of WT1 mutations in NPM1-mutated AML, to enhance our understanding of the biology and potential therapeutic implications of WT1 mutations. Our study cohort included 67 patients with NPM1 mutated AML and a median follow-up of 13.7 months. WT1 mutations were identified in 7% (n = 5) of patients at the time of initial diagnosis. WT1 mutant clones were presumed to be present as co-dominant clones in 3/5 and in subclonal populations in 2/5 cases based on variant allelic frequency (VAF) when compared with NPM1 mutation VAF. All WT1 mutations became undetectable at time of MRD-negative (NPM1-wild type) remission. None of these patients experienced relapse at the time of last follow-up (median, 15 months; range, 4.5-20.2 months). A total of 15/67 (22%) patients relapsed; among these patient, four (27%) relapsed with WT1 mutant AML. Three of four patients had undergone allogeneic hematopoietic stem cell transplantation (HSCT). None of these patients had detectable WT1 mutations at the time of initial diagnosis. WT1 mutations were presumed clonal in two cases and subclonal in the other two cases, based on VAF. Our results indicate that WT1 mutations contribute to relapse in NPM1 mutated AML, especially in the setting of HSCT. These findings suggest that emerging WT1 mutations may serve as a conduit for relapse in NPM1-mutated AML, and that sequential molecular profiling to evaluate potential emergent WT1 mutations during surveillance and particularly at relapse likely has prognostic value in patients with NPM1 mutated AML., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Induction with ibrutinib and rituximab provides an opportunity to minimise chemotherapy exposure, because upfront use of these targeted therapies could result in remission without chemotherapy and allow for consolidation with only four cycles of chemotherapy instead of the conventional eight. We aimed to determine the activity and safety of ibrutinib-rituximab induction followed by shortened chemoimmunotherapy (four cycles) with rituximab plus hyper-fractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (R-HCVAD) alternating with methotrexate-cytarabine in previously untreated patients with mantle cell lymphoma., Methods: We did a single-centre, single-arm, phase 2 trial in previously untreated patients with mantle cell lymphoma. Eligible patients were aged 65 years or younger and had serum bilirubin of less than 1·5 mg/dL, creatinine clearance of 30 mL/min or more, Eastern Cooperative Oncology Group performance status of 2 or less, and cardiac ejection fraction 50% or more by echocardiogram. Patients received 12 cycles of ibrutinib-rituximab induction (part A; oral ibrutinib 560 mg daily and intravenous rituximab 375 mg/m 2 weekly for the first 4 weeks and then on day 1 of cycles 3-12). As soon as patients had a complete response, four cycles of R-HCVAD alternating with methotrexate-cytarabine (part B) were administered. If they did not have a complete response or had a partial response, patients received two cycles of R-HCVAD alternating with methotrexate-cytarabine followed by reassessment, up to a total of eight cycles. Patients were taken off study if they had stable disease or progression during R-HCVAD. The primary outcome was the overall response rate after part A. The analyses were conducted on an intention-to-treat basis. This trial is registered with ClinicalTrials.gov, number NCT02427620., Findings: 131 patients were enrolled between June 12, 2015, and Dec 6, 2018. The median age was 56 years (IQR 49-60). 58 (50%) of 117 patients had high Ki-67 (≥30%). 129 (98%, 95% CI 95-100) of 131 patients had an overall response in part A. The most common grade 3-4 adverse events were lymphocytopenia (19 [14%] of 131), skin rash (16 [12%]), thrombocytopenia (12 [9%]), infections (11 [8%]), and fatigue (ten [8%]) in part A and lymphocytopenia (96 [73%]), leukocytopenia (42 [32%]), thrombocytopenia (40 [30%]), and neutropenia (26 [20%]) in part B. There was one on-study death, which was not deemed to be treatment-related., Interpretation: Induction with ibrutinib-rituximab in the frontline treatment of young patients with mantle cell lymphoma is active and safe. This approach allowed minimisation of the number of chemotherapy cycles, thereby reducing the adverse events associated with chemotherapy. Newer trials bringing the next-generation Bruton's tyrosine kinase inhibitors into the frontline setting might obviate the need for chemotherapy altogether in patients with mantle cell lymphoma., Funding: Pharmacyclics, Janssen., Competing Interests: Declaration of interests MLW reports consultancy for InnoCare, Loxo Oncology, Juno, Oncternal, CStone, AstraZeneca, Janssen, VelosBio, Pharmacyclics, Genentech, and Bayer Healthcare; research funding from Pharmacyclics, Janssen, AstraZeneca, Celgene, Loxo Oncology, Kite Pharma, Juno, BioInvent, VelosBio, Acerta Pharma, Oncternal, Verastem, Molecular Templates, Lilly, and Innocare; and honoraria from Janssen, Acerta Pharma, OMI, Physicians Education Resources, Dava Oncology, CAHON, Hebei Cancer Prevention Federation, Clinical Care Options, Mumbai Hematology Group, Anticancer Association, and Newbridge Pharmaceuticals. PJ reports consultancy for Incyte, Eli Lilly, Aptitude Health, and Kite Pharma; research funding from Kite and AstraZeneca; and honoraria from Aptitude Health. FV reports research funding and support from National Cancer Institute, CRISP Therapeutics, and Geron Corporation; and honoraria from i3Health, Elsevier, America Registry of Pathology, Congressionally Directed Medical Research Program, and Society of Hematology Oncology. CRF has consulted for Abbvie, Bayer, BeiGene, Celgene, Denovo Biopharma, Epizyme, Genentech–Roche, Gilead, Karyopharm, MEI Pharmaceuticals, Pharmacyclics–Janssen, and Spectrum in the past 3 years; and reports research funding in the past 12 months from Abbvie, Acerta, Celgene, Gilead, Genentech–Roche, Janssen Pharmaceutical, Millennium–Takeda, Pharmacyclics, TG Therapeutics, Burroughs Wellcome Fund, CPRIT, Eastern Cooperative Oncology Group, National Cancer Institute, and V Foundation. All other authors declare no competing interests., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Purpose: Most patients with mantle cell lymphoma (MCL) are older. In this study, we investigated the efficacy and safety of a chemotherapy-free combination with ibrutinib and rituximab (IR) in previously untreated older patients with MCL (age ≥ 65 years)., Methods: We enrolled 50 patients with MCL in this single-institution, single-arm, phase II clinical trial (NCT01880567). Patients with Ki-67% ≥ 50% and blastoid morphology were excluded. Ibrutinib was administered with rituximab up to 2 years with continuation of ibrutinib alone. The primary objective was to assess the overall response rate and safety of IR. In evaluable samples, whole-exome sequencing and bulk RNA sequencing from baseline tissue samples were performed., Results: The median age was 71 years (interquartile range 69-76 years). Sixteen percent of patients had high-risk simplified MCL international prognostic index. The Ki-67% was low (< 30%) in 38 (76%) and moderately high (≥ 30%-50%) in 12 (24%) patients. The best overall response rate was 96% (71% complete response). After a median follow-up of 45 months (interquartile range 24-56 months), 28 (56%) patients came off study for various reasons (including four progression, 21 toxicities, and three miscellaneous reasons). The median progression-free survival and overall survival were not reached, and 3-year survival was 87% and 94%, respectively. None of the patients died on study therapy. Notably, 11 (22%) patients had grade 3 atrial fibrillation. Grade 3-4 myelosuppression was seen in < 5% of patients. Differential overexpression of CCND1 , BIRC3 , BANK1 , SETBP1 , AXIN2 , and IL2RA was noted in partial responders compared with patients with complete response., Conclusion: IR combination is effective in older patients with MCL. Baseline evaluation for cardiovascular risks is highly recommended. Randomized trial is needed for definitive conclusions., Competing Interests: Preetesh JainHonoraria: Kite, a Gilead company, LillyConsulting or Advisory Role: Lilly Hun Ju LeeHonoraria: Aptitude Health, Cancer Experts Now, Curio Science, Century TherapeuticsConsulting or Advisory Role: BMS, Guidepoint Global,Research Funding: Seattle Genetics, BMS, Takeda, Oncternal Therapeutics, Celgene, Chi Young OkResearch Funding: Seattle Genetics Fredrick B. HagemeisterConsulting or Advisory Role: Genentech Nathan FowlerEmployment: BostonGeneConsulting or Advisory Role: Roche/Genentech, TG Therapeutics, Verastem, Bayer, Celgene, Novartis,Research Funding: Roche, Celgene, Gilead Sciences, TG Therapeutics, Novartis, Abbvie, BeiGene Luis FayadConsulting or Advisory Role: EUSA Pharma Francisco VegaHonoraria: i3HealthResearch Funding: CRISPR Therapeutics, Geron Christopher R. FlowersThis author is a member of the Journal of Clinical Oncology Editorial Board. Journal policy recused the author from having any role in the peer review of this manuscript.Consulting or Advisory Role: Bayer, Gilead Sciences¸ Spectrum Pharmaceuticals, Abbvie, Celgene, Denovo Biopharma, BeiGene, Karyopharm Therapeutics, Pharmacyclics/Janssen, Genentech/Roche, EpizymeResearch Funding: Acerta Pharma (Inst), Janssen Oncology (Inst), Gilead Sciences (Inst), Celgene (Inst), TG Therapeutics (Inst), Genentech/Roche (Inst), Pharmacyclics (Inst), Abbvie (Inst), Millennium (Inst), Alimera Sciences (Inst), Xencor (Inst) Michael L. WangHonoraria: Janssen Research & Development, DAVA Oncology, OM Pharmaceutical Industries, AstraZeneca, CAHON, Hebei Cancer Prevention Federation, Mumbai Hematology Group, Acerta Pharma, Anticancer Association, BeiGene, Chinese Medical Association, Clinical Care Options, Epizyme, Imbruvica, Imedex, Kite, a Gilead company, Miltenyi Biomedicine GmbH, Moffit Cancer Center, Newbridge Pharmaceuticals, Physicians Education Resources (PER), Scripps, The First Afflicted Hospital of Zhejiang University, BGICS,Consulting or Advisory Role: AstraZeneca, Janssen Research & Development, Juno Therapeutics, Bioinvent, Pharmacyclics/Janssen, Pulse Biosciences, Guidepoint Global, Loxo, Kite, a Gilead company, InnoCare, Oncternal Therapeutics, CStone Pharmaceuticals, Genentech, Bayer, BeiGene, DTRM Biopharma (Cayman) Limited, Epizyme, Miltenyi Biomedicine GmbH, VelosBioResearch Funding: AstraZeneca, Janssen Research & Development, Pharmacyclics, Kite, a Gilead company¸ Juno Therapeutics, BeiGene, Acerta Pharma, Oncternal Therapeutics, Bioinvent, Loxo, Celgene, VelosBio, Molecular Templates, Lilly, InnoCareTravel, Accommodations, Expenses: Janssen Research & Development, AstraZeneca, Celgene, DAVA Oncology, OM Pharmaceutical IndustriesNo other potential conflicts of interest were reported.

Mantle cell lymphoma (MCL) is a mature B-cell neoplasm characterized by t(11;14) (q13;q32) and cyclin D1 overexpression in >95% of cases. Classic MCL cases are composed of a monotonous population of small- to medium-sized lymphocytes with irregular nuclear contours that are positive for cyclin D1 and SOX11 and negative for CD23 and CD200. By contrast, occasional MCL cases express CD23 and CD200 but lack SOX11 and morphologically and immunophenotypically resemble chronic lymphocytic leukemia (CLL), termed as CLL-like MCL in this study. These neoplasms pose a diagnostic challenge and are easy to be diagnosed as CLL in daily practice. We studied 14 cases of CLL-like MCL to define their clinicopathologic features and compared them with 33 traditional CLL cases. There were 8 men and 6 women with a median age of 62 years (range, 44-80). Compared with CLL, patients with CLL-like MCL have lower levels of peripheral blood and bone marrow involvement and more frequently had mutated IGHV. Immunophenotypically, CLL-like MCL often showed moderate to bright expression of B-cell antigens and surface immunoglobulin light chain, dim and partial expression of CD23 and CD200, infrequent CD43 positivity, and lack of LEF1. The overall survival of patients with CLL-like MCL was similar to that of CLL patients. In conclusion, CD23+, CD200+, and SOX11-negative MCL closely resemble CLL, both clinically and pathologically, including a similar indolent clinical course. They may pose a diagnostic challenge. However, patients with CLL-like MCL also have distinctive immunophenotypic features that are useful to distinguish these neoplasms from CLL., (Copyright © 2021 Elsevier Inc. All rights reserved.)

We report 83 cases of mantle cell lymphoma (MCL) involving the tonsil as initial manifestation (IM). The median age at the time of tonsillar involvement was 58 years (range, 35-79 years). Most (85%) patients presented similar to acute tonsillitis. Lymphadenopathy (84%) and advanced stage of disease (81%) were frequent. With a median follow-up of 6.1 years (range, 0.5-18.4 years), the median overall survival (OS) was 11.3 years for all patients. Cases with classic MCL morphology demonstrated a superior OS (median OS: 11.7 years versus 7.8 years for aggressive morphology, P = 0.0361). Approximately 20% of patients had limited stage of disease, and they had excellent outcomes (median OS: not reached versus 11.3 years for advanced-stage MCL, P = 0.0479). All the patients were alive after a median follow-up of 6.6 years (range, 1-16.2 years). There were no differences in relapse-free survival in morphology and stage (P > 0.05). When tonsils were involved by relapsed MCL, patients less commonly had acute tonsillitis-like symptoms, lymphadenopathy, and advanced stage of disease compared to MCL as IM. Patients in the relapse group had poorer OS than patients in the IM group from the time of tonsillar involvement by MCL to the date of death or last follow-up (7.8 versus 11.7 years, P = 0.003). Compared with a group of 93 patients whose initial biopsy specimen was a lymph node, patients whose initial biopsy specimen was tonsil had similar OS (11.7 versus 8.8 years, P = 0.1764). However, patients with tonsillar MCL more commonly had limited stage disease (19% versus 8%, P = 0.0385) and a low-risk Mantle Cell Lymphoma International Prognostic Index score (71% versus 47%, P = 0.0025)., (Copyright © 2021. Published by Elsevier Inc.)

Enhancer of zeste homolog 2 (EZH2) is a catalytic component of the polycomb repressive complex 2 (PRC2) which reduces gene expression via trimethylation of a lysine residue of histone 3 (H3K27me3). Expression of EZH2 has not been assessed systematically in mantle cell lymphoma (MCL). Expression of EZH2 was assessed by immunohistochemistry in 166 patients with MCL. We also assessed other PRC2 components and H3K27me3. Fifty-seven (38%) of MCL patients were positive for EZH2 using 40% cutoff. EZH2 expression was associated with aggressive histologic variants (65% vs. 29%, p < 0.001), high Ki-67 proliferation rate (median, 72% vs. 19%, p < 0.001), and p53 overexpression (43% vs. 2%, p < 0.001). EZH2 expression did not correlate with expression of other PRC2 components (EED and SUZ12), H3K27me3, MHC-I, and MHC-II. Patients with EZH2 expression (EZH2+) had a poorer overall survival (OS) compared with patients without EZH2 expression (EZH2-) (median OS: 3.9 years versus 9.4 years, respectively, p < 0.001). EZH2 expression also predicted a poorer prognosis in MCL patients with classic histology (median OS, 4.6 years for EZH2+ and 9.6 years for EZH2-negative, respectively, p < 0.001) as well as aggressive histology (median OS, 3.7 years for EZH2+ and 7.9 years for EZH2-negative, respectively, p = 0.046). However, EZH2 expression did not independently correlate with overall survival in a multivariate analysis. Gene expression analysis and pathway enrichment analysis demonstrated a significant enrichment in cell cycle and mitotic transition pathways in MCL with EZH2 expression. EZH2 expression detected by immunohistochemistry is present in 38% of MCL cases and it is associated with high proliferation rate, p53 overexpression, aggressive histologic variants, and poorer OS. Based on gene expression profiling data, EZH2 expression could potentiate cell cycle machinery in MCL. These data suggest that assessment of EZH2 expression could be useful to stratify MCL patients into low- and high-risk groups., (© 2021. The Author(s), under exclusive licence to United States & Canadian Academy of Pathology.)

Breast implant-associated anaplastic large cell lymphoma (ALCL) is a distinctive type of T-cell lymphoma that arises around textured-surface breast implants. In a subset of patients, this disease can involve surrounding tissues, spread to regional lymph nodes, and rarely metastasize to distant sites. The aim of this study was to assess sequential pathologic specimens from patients with breast implant-associated ALCL to better understand the natural history of early-stage disease. To achieve this goal, we searched our files for patients who had breast implant-associated ALCL and who had undergone earlier surgical intervention with assessment of biopsy or cytologic specimens. We then focused on the patient subset in whom a definitive diagnosis was not established, and patients did not receive current standard-of-care therapy at that time. We identified a study group of ten patients with breast implant-associated ALCL in whom pathologic specimens were collected 0.5 to 4 years before a definitive diagnosis was established. A comparison of these serial biopsy specimens showed persistent disease without change in pathologic stage in three patients, progression in five patients, and persistence versus progression in two patients. Eventually, six patients underwent implant removal with complete capsulectomy and four underwent partial capsulectomy. Seven patients also received chemotherapy because of invasive disease, three of whom also received radiation therapy, two brentuximab vedotin after chemotherapy failure, and one allogeneic stem cell transplant. Eight patients achieved complete remission and two had partial remission after definitive therapy. At time of last follow-up, six patients were alive without disease, one had evidence of disease, one died of disease, and two patients died of unrelated cancers. In summary, this analysis of sequential specimens from patients with breast implant-associated ALCL suggests these neoplasms persist or progress over time if not treated with standard-of-care therapy., (© 2021. The Author(s), under exclusive licence to United States & Canadian Academy of Pathology.)