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Recent studies have revealed an association between TP53 mutations and endocrine resistance in hormone receptor-positive, HER2-negative breast cancer (HR + HER2 -BC). Aberrant p53 immunostaining (IHC) patterns may provide a surrogate marker for TP53 mutations. Building upon a ternary algorithm of aberrant staining patterns, this study evaluates the reliability of p53 IHC as screening tool for TP53 mutations in BC (NST). Furthermore, it describes the histopathological and molecular characteristics of TP53-mutated cases, along with the mutational status of PIK3CA. This study comprised 131 early-stage, node-negative BCs with available core biopsies and resection specimens. Cases were categorized as follows: HR + HER2 - (85 cases), HER2 + (21 cases) and triple negative (TN, 25 cases). Aberrant IHC staining patterns for p53 were defined as overexpression (OE), complete absence (CA) and cytoplasmic (CY). In addition, targeted sequencing of TP53 and PIK3CA genes was performed. TP53 mutations were identified in 53 of 126 cases (42.1%). Within HR + HER2 - cases, TP53 mutations were found in 17 of 80 cases (21.3%). IHC accurately predicted TP53 mutation in 96.2% of cases with a specificity of 100%. Additionally, there was a significant agreement between missense mutations and OE, as well as between truncating mutations and CA (κ 73% and 76%). CY was observed in two TN cases with truncating mutations within the nuclear localization signalling domain of p53. TP53-mutated cases exhibited higher grade, greater nuclear pleomorphism and higher Ki-67 proliferation index and were associated with the PIK3CA wild-type status (p < 0.001). p53 IHC may provide a useful screening tool for identifying TP53-mutated BC of NST., (© 2024. The Author(s).)

Abstract: Burkitt lymphoma (BL) is characterized by a tumor microenvironment (TME) in which macrophages represent the main component, determining a distinct histological appearance known as "starry sky" pattern. However, in some instances, BL may exhibit a granulomatous reaction that has been previously linked to favorable prognosis and spontaneous regression. The aim of our study was to deeply characterize the immune landscape of 7 cases of Epstein-Barr virus-positive (EBV+) BL with granulomatous reaction compared with 8 cases of EBV+ BL and 8 EBV-negative (EBV-) BL, both with typical starry sky pattern, by Gene expression profiling performed on the NanoString nCounter platform. Subsequently, the data were validated using multiplex and combined immunostaining. Based on unsupervised clustering of differentially expressed genes, BL samples formed 3 distinct clusters differentially enriched in BL with a diffuse granulomatous reaction (cluster 1), EBV+ BL with typical starry sky pattern (cluster 2), EBV- BL with typical "starry sky" (cluster 3). We observed variations in the immune response signature among BL with granulomatous reaction and BL with typical "starry sky," both EBV+ and EBV-. The TME signature in BL with diffuse granulomatous reaction showed a proinflammatory response, whereas BLs with "starry sky" were characterized by upregulation of M2 polarization and protumor response. Moreover, the analysis of additional signatures revealed an upregulation of the dark zone signature and epigenetic signature in BL with a typical starry sky. Tumor-associated macrophages and epigenetic regulators may be promising targets for additional therapies for BL lymphoma, opening novel immunotherapeutic strategies., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht.

Cancer affects the mechanical properties of tissue. Therefore, elastography techniques can be used to differentiate cancerous from healthy tissue. Due to probe size and restricted handling, most elastography techniques are not applicable in minimally invasive surgery (MIS). Established techniques such as endoscopic ultrasound elastography measure under undefined boundary conditions, making the determination of quantitative mechanical properties challenging. Water flow elastography (WaFE) has recently been introduced for application in MIS. Here, we present an improved WaFE measurement method in which the probe attaches itself to the sample with a small suction pressure. This leads to defined boundary conditions, allowing for a quantitative determination of the Young's modulus of tissue. To facilitate fast measurements, we developed a correction model for the hydrodynamic resistance and the fluid inertia of the tubing. We used WaFE for ex vivo measurements on human bladders and found a significantly larger Young's modulus for cancerous vs. healthy tissue. We determined the optimal classification threshold for the Young's modulus to be 8 kPa and found that WaFE can differentiate between cancerous and healthy tissue with a sensitivity of 0.96 and a specificity of 1. Our results underline that WaFE can be a helpful differentiating tool in MIS., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

In critically ill patients infected with SARS-CoV-2, early leukocyte recruitment to the respiratory system was found to be orchestrated by leukocyte trafficking molecules accompanied by massive secretion of proinflammatory cytokines and hypercoagulability. Our study aimed to explore the interplay between leukocyte activation and pulmonary endothelium in different disease stages of fatal COVID-19. Our study comprised 10 COVID-19 postmortem lung specimens and 20 control lung samples (5 acute respiratory distress syndrome, 2 viral pneumonia, 3 bacterial pneumonia, and 10 normal), which were stained for antigens representing the different steps of leukocyte migration: E-selectin, P-selectin, PSGL-1, ICAM1, VCAM1, and CD11b. Image analysis software QuPath was used for quantification of positive leukocytes (PSGL-1 and CD11b) and endothelium (E-selectin, P-selectin, ICAM1, VCAM1). Expression of IL-6 and IL-1β was quantified by RT-qPCR. Expression of P-selectin and PSGL-1 was strongly increased in the COVID-19 cohort compared with all control groups (COVID-19:Controls, 17:23, P < .0001; COVID-19:Controls, 2:75, P < .0001, respectively). Importantly, P-selectin was found in endothelial cells and associated with aggregates of activated platelets adherent to the endothelial surface in COVID-19 cases. In addition, PSGL-1 staining disclosed positive perivascular leukocyte cuffs, reflecting capillaritis. Moreover, CD11b showed a strongly increased positivity in COVID-19 compared with all controls (COVID-19:Controls, 2:89; P = .0002), indicating a proinflammatory immune microenvironment. Of note, CD11b exhibited distinct staining patterns at different stages of COVID-19 disease. Only in cases with very short disease course, high levels of IL-1β and IL-6 mRNA were observed in lung tissue. The striking upregulation of PSGL-1 and P-selectin reflects the activation of this receptor-ligand pair in COVID-19, increasing the efficiency of initial leukocyte recruitment, thus promoting tissue damage and immunothrombosis. Our results show that endothelial activation and unbalanced leukocyte migration play a central role in COVID-19 involving the P-selectin-PSGL-1 axis., (Copyright © 2023 United States & Canadian Academy of Pathology. Published by Elsevier Inc. All rights reserved.)

Aims: COVID-19 has had enormous consequences on global health-care and has resulted in millions of fatalities. The exact mechanism and site of SARS-CoV-2 entry into the body remains insufficiently understood. Recently, novel virus receptors were identified, and alveolar macrophages were suggested as a potential viral entry cell type and vector for intra-alveolar virus transmission. Here, we investigated the protein expression of 10 well-known and novel virus entry molecules along potential entry sites in humans using immunohistochemistry., Methods and Results: Samples of different anatomical sites from up to 93 patients were incorporated into tissue microarrays. Protein expression of ACE2, TMPRSS2, furin, CD147, C-type lectin receptors (CD169, CD209, CD299), neuropilin-1, ASGR1 and KREMEN1 were analysed. In lung tissues, at least one of the three receptors ACE2, ASGR1 or KREMEN1 was expressed in the majority of cases. Moreover, all the investigated molecules were found to be expressed in alveolar macrophages, and co-localisation with SARS-CoV-2 N-protein was demonstrated using dual immunohistochemistry in lung tissue from a COVID-19 autopsy. While CD169 and CD209 showed consistent protein expression in sinonasal, conjunctival and bronchiolar tissues, neuropilin-1 and ASGR1 were mostly absent, suggesting a minor relevance of these two molecules at these specific sites., Conclusion: Our results extend recent discoveries indicating a role for these molecules in virus entry at different anatomical sites. Moreover, they support the notion of alveolar macrophages being a potential entry cell for SARS-CoV-2., (© 2023 The Authors. Histopathology published by John Wiley & Sons Ltd.)

Congenital Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome is a Mullerian-duct anomaly that is characterized by agenesis of the uterus and upper part of the vagina. Uterus remnants of varying sizes can often be found. Although a functional uterus is missing, the existence of endometriosis in this patient group has been described in the literature; however, a histopathological comparison of the characteristics of the endometrium within the uterus remnants versus endometriotic peritoneal lesions in the same patient is lacking. Moreover, the characteristics of endometriotic tissue in patients with MRKH syndrome have not been correlated with those of patients with endometriosis without Mullerian anomaly. Patients who underwent laparoscopic neovagina creation with the removal of uterus remnants and possible resection of endometriotic lesions between 2010 and 2022 at the Department of Women's health of the University of Tuebingen were included in our study. Uterine remnants and endometriotic tissue were evaluated via histopathology and immunohistochemistry and were compared to endometriotic samples from patients without Mullerian anomaly. Endometriosis was detected in nine MRKH patients; in four patients, endometrial remnants could be sufficiently compared to endometriotic lesions. All samples exhibited increased expression of hormonal receptors. In two patients, Ki67 proliferation index was significantly increased in peritoneal endometriotic lesions compared with the endometrium of the remnants. In contrast, endometrium and endometriotic lesions of endometriosis patients did not exhibit any differences in the Ki67 proliferation index. Our results demonstrate distinctive immunohistochemical variability between uterine remnants and endometriotic lesions in patients with MRKH syndrome compared with patients with endometriosis, indicating a possible explanation model of the yet-unknown etiology of endometriosis. For confirmation, investigation of a broader patient collective is necessary.

Introduction: Sentinel node biopsy is a key procedure to predict prognosis in melanoma. In a prospective study we compare reporting on melanoma cell densities in cytospin preparations with semiquantitative histopathology for predicting outcome., Patients and Methods: Sentinel nodes from 900 melanoma patients were bisected. One half of each node was disaggregated mechanically. The melanoma cell density (number of HMB45 positive cells per million lymphocytes with at least one cell showing morphological features of a melanoma cell) was recorded after examining two cytospins. For the second half the maximum diameter of metastasis was determined after haematoxylin and eosin (H&E) and immunohistological staining of three slides., Results: Cytospins were positive for melanoma in 218 of 900 patients (24%). Routine pathology was positive in 111 of 900 (12%) patients. A more extensive pathological workup in cytospin-only positive patients led to a revised diagnosis (from negative to positive) in 23 of 101 patients (22.7%). We found a moderate but significant correlation between melanoma cell densities (determined in cytospins) and the maximum diameter of metastasis (determined by pathology) (rho = 0.6284, p &lt; 0.001). At a median follow-up of 37 months (IQR 25-53 months) melanoma cell density (cytospins) (p &lt; 0.001), thickness of melanoma (p = 0.008) and ulceration status (p = 0.026) were significant predictors for melanoma specific survival by multivariable testing and were all confirmed as key predictive factors by the random forest model. Maximum diameter of metastases, age and sex were not significant by multivariable testing (all p &gt; 0.05)., Conclusion: Recording melanoma cell densities by examining two cytospins accurately predicts melanoma outcome and outperforms semiquantitative histopathology., Competing Interests: Conflict of interest statement The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Background: To the best of our knowledge, this case represents the first report of an extranodal double-hit follicular lymphoma (DH-FL) as an intestinal polypoid lesion., Case Presentation: A 72-year-old woman presents with constipation. Colonoscopy reveals a sessile polypoid lesion of the colon bearing morphological, immunohistochemical and molecular hallmarks of DH-FL. Complete clinical staging and bone marrow biopsy showed no signs of disseminated disease. The patient, after two years of follow-up is still free of disease confirming the indolent behaviour of this limited lesion., Conclusions: A synoptic view at all the features of the patient and not merely at the molecular hallmarks of a disease are essential to establish the correct clinical approach., (© 2022. The Author(s).)

Burkitt lymphoma (BL) is a malignant B cell neoplasm that accounts for almost half of pediatric cancers in sub-Saharan African countries. Although the BL endemic prevalence is attributable to the combination of Epstein-Barr virus (EBV) infection with malaria and environmental carcinogens exposure, such as the food contaminant aflatoxin B1 (AFB1), the molecular determinants underlying the pathogenesis are not fully understood. Consistent with the role of epigenetic mechanisms at the interface between the genome and environment, AFB1 and EBV impact the methylome of respectively leukocytes and B cells specifically. Here, we conducted a thorough investigation of common epigenomic changes following EBV or AFB1 exposure in B cells. Genome-wide DNA methylation profiling identified an EBV-AFB1 common signature within the TGFBI locus, which encodes for a putative tumor suppressor often altered in cancer. Subsequent mechanistic analyses confirmed a DNA-methylation-dependent transcriptional silencing of TGFBI involving the recruitment of DNMT1 methyltransferase that is associated with an activation of the NF-κB pathway. Our results reveal a potential common mechanism of B cell transformation shared by the main risk factors of endemic BL (EBV and AFB1), suggesting a key determinant of disease that could allow the development of more efficient targeted therapeutic strategies.

The gastrointestinal (GI) tract may be involved in systemic autoimmune diseases or may be the target of organ-specific autoimmunity. Autoimmune enteropathy (AIE) is a rare disorder characterized by severe and protracted diarrhea, weight loss from malabsorption and immune-mediated damage to the intestinal mucosa, generally occurring in infants and young children, only rarely in adult. The salient histopathologic features of AIE are most prominent in the small intestine: villous blunting, crypt hyperplasia, mononuclear cell inflammatory expansion of the lamina propria with intraepithelial lymphocytosis, crypt apoptosis and absence of Paneth cells, goblet cells or both. Esophagus, stomach and colon are frequently also involved. Anti-enterocyte antibodies are identified in the majority of cases, and their presence, even if variable, can help confirming the diagnosis., The purpose of this review is to provide an overview of the latest immunological advances in AIE, as well as to offer a practical approach for histological diagnosis for 'general' pathologist., (Copyright © 2022 Società Italiana di Anatomia Patologica e Citopatologia Diagnostica, Divisione Italiana della International Academy of Pathology.)

Classic Hodgkin lymphoma (CHL) is a well-defined neoplasm characterized by the presence of a minority of pathognomonic Hodgkin and Reed-Sternberg (HRS) cells in a reactive inflammatory background. Although genotypically of B cell origin, HRS cells exhibit a downregulated B cell program and therefore are set apart from other B cell lymphomas in the current WHO classification. However, cases with morphological and phenotypic features overlapping with CHL have been recognized, and the category of B cell lymphoma-unclassifiable-with features intermediate between diffuse large B cell lymphoma (DLBCL) and CHL, also termed grey zone lymphoma, was first introduced into the WHO classification in 2008 as provisional entity. These cases, as well as others raising a differential diagnosis of CHL can present diagnostic problems, as well as therapeutic challenges. Whereas some of these lymphomas only represent biologically unrelated morphological mimics, others, especially mediastinal grey zone lymphoma, exhibit genetic and gene expression profiles which overlap with CHL, indicating a true biological relationship. In this review, we address areas of diagnostic difficulties between CHL and other lymphoma subtypes, discuss the biological basis of true grey zone lymphoma based on recent molecular studies and delineate current concepts for the classification of these rare tumors.

Aims: Burkitt lymphoma (BL) is an aggressive B-cell lymphoma that, in some instances, may show a granulomatous reaction associated with a favourable prognosis and occasional spontaneous regression. In the present study, we aimed to define the tumour microenvironment (TME) in four such cases, two of which regressed spontaneously., Methods and Results: All cases showed aggregates of tumour cells with the typical morphology, molecular cytogenetics and immunophenotype of BL surrounded by a florid epithelioid granulomatous reaction. All four cases were Epstein-Barr virus (EBV)-positive with type I latency. Investigation of the TME showed similar features in all four cases. The analysis revealed a proinflammatory response triggered by Th1 lymphocytes and M1 polarised macrophages encircling the neoplastic cells with a peculiar topographic distribution., Conclusions: Our data provide an in-vivo picture of the role that specific immune cell subsets might play during the early phase of BL, which may be capable of maintaining the tumour in a self-limited state or inducing its regression. These novel results may provide insights into new potential therapeutic avenues in EBV-positive BL patients in the era of cellular immunotherapy., (© 2021 The Authors. Histopathology published by John Wiley & Sons Ltd.)

Background: Human herpesvirus-8 (HHV8) is a lymphotropic virus associated with different lymphoproliferative disorders, including primary effusion lymphoma (PEL), multicentric Castleman's disease (MCD), diffuse large B-cell lymphomas, not otherwise specified, and the rare entity known as germinotropic lymphoproliferative disorder (GLPD). In PELs and GLPD the neoplastic cells also contain Epstein-Barr virus (EBV). In addition, occasional cases with atypical and overlapping features among these entities have been recognised, suggesting that the spectrum of the HHV8-related lesions may not be fully characterised., Aims: Here, we report two cases of lymphoproliferative disorder associated with HHV8 and EBV that further expand the spectrum of HHV8/EBV-positive lymphoproliferative disease., Methods and Results: Case 1 represented HHV8/EBV-positive extracavitary nodal PEL followed by pleural PEL. The striking characteristic of this case was the almost focal and intrasinusoidal localisation of the neoplastic cells and the association with Castleman's disease features. In the second case, we found the entire spectrum of HHV8-related disorders, i.e. MCD, GLPD, and PEL, coexisting in the same lymph node, underlining the variability, possible overlap and evolution among these entities. Both cases were well analysed with immunohistochemistry, determination of the EBV latency programme, and molecular analysis for clonality of immnoglobulin genes. In both patients, the disease followed an unexpected indolent course, both being still alive after 8 and 12 months, respectively., Conclusion: Our findings represent further evidence of the overlap among HHV8/EBV-positive lymphoproliferative disorders, and underline a grey zone that requires further study; they further confirm the experimental evidence that lytic EBV replication influences HHV8-related tumorigenesis., (© 2021 The Authors. Histopathology published by John Wiley & Sons Ltd.)

Altered cellular energetic metabolism has recently emerged as important feature of neoplastic cells. Indeed, interfering with cancer cell metabolism might represent a suitable therapeutic strategy. In this study, we aimed to assess glucose metabolism activation in human lymphomas and evaluate how metformin can exert its action on lymphoma cells. We studied a large series of human lymphomas (N = 252) and an in vitro model of Burkitt lymphoma (BL) cells. We combined molecular biology techniques, including global gene expression profiling (GEP) analysis, quantitative PCR (qPCR) and Western blotting, and biochemical assays, aimed to assess pentose phosphate pathway, tricarboxylic acid (TCA) cycle, and aerobic glycolysis rates. We found that glucose metabolism is overall enhanced in most lymphoma subtypes, based on gene expression profiling (GEP), with general shift to aerobic glycolysis. By contrast, normal B cells only showed an overall increase in glucose usage during germinal center transition. Interestingly, not only highly proliferating aggressive lymphomas but also indolent ones, like marginal zone lymphomas, showed the phenomenon. Consistently, genes involved in glycolysis were confirmed to be overexpressed in BL cells by qPCR. Biochemical assays showed that while aerobic glycolysis is increased, TCA cycle is reduced. Finally, we showed that metformin can induce cell death in BL cells by stressing cellular metabolism through the induction of GLUT1, PKM2, and LDHA. In conclusion, we unveiled glucose metabolism abnormalities in human lymphomas and characterized the mechanism of action of metformin in Burkitt lymphoma model., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Bagaloni, Visani, Biagiotti, Ruzzo, Navari, Etebari, Mundo, Granai, Lazzi, Isidori, Loscocco, Li, Leoncini, Visani, Magnani and Piccaluga.)

BACKGROUND Erdheim-Chester disease (ECD) is a rare form of non-Langerhans cell histiocytosis characterized by foamy histiocytes, Touton-like giant cells, and fibrosis, typically affecting the diaphyseal and metaphyseal region of the long bones but that can involve any organ or tissue. ECD is usually associated with the BRAF V600E mutation or with other molecular mutations inserted in the MAPK cascade. CASE REPORT We present the case of a 63-year-old man with a previous history of myocardial infarction who underwent an emergency splenectomy for splenic rupture after an accidental fall. Histological examination of the spleen showed a diffuse xanthogranulomatous proliferation (CD68+, CD163+, S100-, CD1a-) with rare Touton-like giant cells in the red pulp. Based on the histologic findings, a diagnosis of ECD was made. However, skeletal involvement and BRAF V600E mutation were not detected. CONCLUSIONS Cases of non-Langerhans cell histiocytosis that are histologically consistent with ECD in unusual sites have been increasingly described. There is also anecdotal evidence for cases being associated with mutations besides BRAF V600E or with no genetic alteration and no skeletal involvement. Likewise, the spectrum of clinical and molecular features of ECD can be broader than previously considered. Furthermore, there is evidence that various phases of the disease can show different clinical presentations with distinct prognostic impact, according to the mutational spectrum. Recognizing ECD at an early stage allows more effective patient management, and pathologists and clinicians should be aware of the unusual clinical presentations of this rare condition.

Post-transplant lymphoproliferative disorders (PTLD) occur after solid organ transplantation (SOT) or hematopoietic stem cell transplantation (HCT) and are frequently associated with Epstein-Barr virus (EBV). Because of the complex immune setup in PTLD patients, the tumor microenvironment (TME) is of particular interest to understand PTLD pathogenesis and elucidate predictive factors and possible treatment options. We present a comparative study of clinicopathological features of 48 PTLD after HCT (n = 26) or SOT (n = 22), including non-destructive (n = 6), polymorphic (n = 23), and monomorphic (n = 18) PTLD and classic Hodgkin lymphoma (n = 1). EBV was positive in 35 cases (73%). A detailed examination of the TME with image analysis-based quantification in 22 cases revealed an inflammatory TME despite underlying immunosuppression and significant differences in its density and composition depending on type of transplant, PTLD subtypes, and EBV status. Tumor-associated macrophages (TAMs) expressing CD163 (p = 0.0022) and Mannose (p = 0.0016) were enriched in PTLD after HCT. Double stains also showed differences in macrophage polarization, with more frequent M1 polarization after HCT (p = 0.0321). Higher counts for TAMs (CD163 (p = 0.0008) and cMaf (p = 0.0035)) as well as in the T cell compartment (Granzyme B (p = 0.0028), CD8 (p = 0.01), and for PD-L1 (p = 0.0305)) were observed depending on EBV status. In conclusion, despite the presence of immunosuppression, PTLD predominantly contains an inflammatory TME characterized by mostly M1-polarized macrophages and cytotoxic T cells. Status post HCT, EBV positivity, and polymorphic subtype are associated with an actively inflamed TME, indicating a specific response of the immune system. Further studies need to elucidate prognostic significance and potential therapeutic implications of the TME in PTLD.

Background: The present study aimed to classify lymphoid neoplasms according to the latest World Health Organization (WHO) classification and outlining the distribution in Nigeria of different entities. Additionally, the study describes the prevalence of lymphoid neoplasms associated with Epstein-Barr virus (EBV) infection in the Nigerian population., Methods: We collected 152 formalin-fixed paraffin-embedded (FFPE) tissues diagnosed as lymphoma from 2008 to 2018, coming from three different institutions located within three geopolitical zone in Nigeria. These institutions included the University College Hospital (UCH), Ibadan, Oyo State, the Enugu State University of Science and Technology Teaching Hospital (ESUTH), Enugu, Enugu State, and the Meena Histopathology and Cytology Laboratory (MHCL), Jos, Plateau State., Results: From the total 152 cases retrieved, 50 were excluded due to insufficient tissue materials or inconclusive antigen reactivity. We confirmed 66 (64.7%) cases as lymphomas out of the remaining 102 FFPE with a male to female ratio of 2:1 and a mean age of 44.4 years. Ten entities were identified, and of these, chronic lymphocytic leukemia (CLL) was the most prevalent category (34.8%). For the diffuse large B-cell lymphomas not otherwise specified (DLBCL, NOS), the germinal centre B-cell type was the most common (71.4%). Ten lymphoma cases (15.2%) were positive for Epstein-Barr virus (EBV), most of which were Hodgkin lymphoma (HL). CLL was common in the Hausa ethnic group, HL in the Yoruba ethnic group, while the Igbo ethnic group had an equal distribution of CLL, HL, and DLBCL diagnosis., Conclusion: Although the distribution of lymphomas in Nigeria shares some similarities with those of other countries, we described distinct features of some subtypes of lymphomas. Also, the study underscores the need for a more precise diagnosis and classification of lymphoid neoplasms in Nigeria using the latest WHO classification.

The Epstein-Barr virus (EBV) is linked to various B-cell lymphomas, including Burkitt lymphoma (BL), classical Hodgkin lymphoma (cHL) and diffuse large B-cell lymphoma (DLBCL) at frequencies ranging, by routine techniques, from 5 to 10% of cases in DLBCL to >95% in endemic BL. Using higher-sensitivity methods, we recently detected EBV traces in a few EBV-negative BL cases, possibly suggesting a "hit-and-run" mechanism. Here, we used routine and higher-sensitivity methods (qPCR and ddPCR for conserved EBV genomic regions and miRNAs on microdissected tumor cells; EBNA1 mRNA In situ detection by RNAscope) to assess EBV infection in a larger lymphoma cohort [19 BL, 34 DLBCL, 44 cHL, 50 follicular lymphomas (FL), 10 T-lymphoblastic lymphomas (T-LL), 20 hairy cell leukemias (HCL), 10 mantle cell lymphomas (MCL)], as well as in several lymphoma cell lines (9 cHL and 6 BL). qPCR, ddPCR, and RNAscope consistently documented the presence of multiple EBV nucleic acids in rare tumor cells of several cases EBV-negative by conventional methods that all belonged to lymphoma entities clearly related to EBV (BL, 6/9 cases; cHL, 16/32 cases; DLBCL, 11/30 cases), in contrast to fewer cases (3/47 cases) of FL (where the role of EBV is more elusive) and no cases (0/40) of control lymphomas unrelated to EBV (HCL, T-LL, MCL). Similarly, we revealed traces of EBV infection in 4/5 BL and 6/7 HL cell lines otherwise conventionally classified as EBV negative. Interestingly, additional EBV-positive cases (1 DLBCL, 2 cHL) relapsed as EBV-negative by routine methods while showing EBNA1 expression in rare tumor cells by RNAscope. The relapse specimens were clonally identical to their onset biopsies, indicating that the lymphoma clone can largely loose the EBV genome over time but traces of EBV infection are still detectable by high-sensitivity methods. We suggest EBV may contribute to lymphoma pathogenesis more widely than currently acknowledged.

Introduction: Microenvironment has a prognostic influence in diffuse large B-cell lymphoma (DLBCL); among its components, tumor-associated macrophages (TAM) play a leading role. TAM can be classified into M1 (anti-tumor) and M2 (pro-tumor). Another prognostic factor could be represented by lymphocyte-to-monocyte and neutrophil-to-lymphocyte ratio (LMR and NLR)., Objective: The aim of the study is to evaluate the prognostic impact of M1 and M2 TAM subtypes, LMR and NLR in DLBCL., Methods: We analyzed 37 consecutive patients between 2009 and 2013. Out of 37 patients, 28/37 (75.6%) received R-CHOP/CHOP-like regimens, 9/37 (24.4%) less intensive therapies. Immunohistochemistry was performed with antibodies against CD68 and CD163. We divided our cohort into 2 categories according to the Steidl score. TAM who coexpressed CD68 and CD163 were considered as M2. For LMR and NLR we used previously published cut-offs of 2.71 and 2.81., Results: CR rate was 70.3%; we did not record a significant correlation between CD68+ TAM, CD163+ TAM, CD68+/CD163+ TAM, LMR, NLR and CR. We observed a reduced PFS in patients with IPI ≥ 2 and high M2 TAM expression and a trend between higher expression of CD68+ TAM and improved PFS., Conclusion: M2 TAM could have a prognostic role for IPI ≥ 2 DLBCL patients receiving R-CHOP, which thus warrants further investigation., Competing Interests: None., (AJBR Copyright © 2020.)

This error was caused due to the author's oversight and this does not change the views or the results presented in the manuscript.

The precise B cell of origin and molecular pathogenesis of nodal marginal zone lymphoma (NMZL) remain poorly defined. To date, due to the rarity of NMZL, the vast majority of already-published studies have been conducted on a limited number of samples and the technical approach to analyze the immunoglobulin genes was of amplifying rearranged variable region genes with the classical direct sequencing of the PCR products followed by cloning. Here, we studied the B cell Ig heavy-chain repertoires by next-generation sequencing (NGS) in 30 NMZL cases. Most of the cases were mutated (20/28; 71.5%) with homologies to the respective germ line genes ranging from 85 to 97, 83%, whereas 8/28 (28.5%) were unmutated. In addition, our results show that NMZL cases have a biased usage of specific immunoglobulin heavy-chain variable (IGHV) region genes. Moreover, we documented intraclonal diversity in all (100%) of the mutated cases and ongoing somatic hypermutations (SHM) have been confirmed by hundreds of reads. We analyzed the mutational pattern to detect and quantify antigen selection pressure and we found a positive selection in 4 cases, whereas in the remaining cases there was an unspecific stimulation. Finally, the disease-specific survival and the progression-free survival were significantly different between cases with mutated and unmutated IGHV genes, pointing out mutational status as a possible new biomarker in NMZL.

Background: The Tumor Microenviroment (TME) is a complex milieu that is increasingly recognized as a key factor in multiple stages of disease progression and responses to therapy as well as escape from immune surveillance. However, the precise contribution of specific immune effector and immune suppressor components of the TME in Burkitt lymphoma (BL) remains poorly understood., Methods: In this paper, we applied the computational algorithm CIBERSORT to Gene Expression Profiling (GEP) datasets of 40 BL samples to draw a map of immune and stromal components of TME. Furthermore, by multiple immunohistochemistry (IHC) and multispectral immunofluorescence (IF), we investigated the TME of additional series of 40 BL cases to evaluate the role of the Programmed Death-1 and Programmed Death Ligand-1 (PD-1/PD-L1) immune checkpoint axis., Results: Our results indicate that M2 polarized macrophages are the most prominent TME component in BL. In addition, we investigated the correlation between PD-L1 and latent membrane protein-2A (LMP2A) expression on tumour cells, highlighting a subgroup of BL cases characterized by a non-canonical latency program of EBV with an activated PD-L1 pathway., Conclusion: In conclusion, our study analysed the TME in BL and identified a tolerogenic immune signature highlighting new potential therapeutic targets., Competing Interests: Competing interestsThe authors declare that they have no competing interests., (© The Author(s) 2020.)

MYC is the most altered oncogene in human cancer, and belongs to a large family of genes, including MYCN and MYCL. Recently, while assessing the degree of correlation between MYC gene rearrangement and MYC protein expression in aggressive B-cell lymphomas, we observed few Burkitt lymphoma (BL) cases lacking MYC protein expression despite the translocation involving the MYC gene. Therefore, in the present study we aimed to better characterize such cases. Our results identified two sub-groups of MYC protein negative BL: one lacking detectable MYC protein expression but presenting MYCN mRNA and protein expression; the second characterized by the lack of both MYC and MYCN proteins but showing MYC mRNA. Interestingly, the two sub-groups presented a different pattern of SNVs affecting MYC gene family members that may induce the switch from MYC to MYCN. Particulary, MYCN-expressing cases show MYCN SNVs at interaction interface that stabilize the protein associated with loss-of-function of MYC. This finding highlights MYCN as a reliable diagnostic marker in such cases. Nevertheless, due to the overlapping clinic, morphology and immunohistochemistry (apart for MYC versus MYCN protein expression) of both sub-groups, the described cases represent bona fide BL according to the current criteria of the World Health Organization.

The Shc family adaptor p66Shc acts as a negative regulator of proliferative and survival signals triggered by the B-cell receptor and, by enhancing the production of reactive oxygen species, promotes oxidative stress-dependent apoptosis. Additionally, p66Shc controls the expression and function of chemokine receptors that regulate lymphocyte traffic. Chronic lymphocytic leukemia cells have a p66Shc expression defect which contributes to their extended survival and correlates with poor prognosis. We analyzed the impact of p66Shc ablation on disease severity and progression in the Eμ-TCL1 mouse model of chronic lymphocytic leukemia. We showed that Eμ-TCL1/p66Shc -/- mice developed an aggressive disease that had an earlier onset, occurred at a higher incidence and led to earlier death compared to that in Eμ-TCL1 mice. Eμ-TCL1/p66Shc -/- mice displayed substantial leukemic cell accumulation in both nodal and extranodal sites. The target organ selectivity correlated with upregulation of chemokine receptors whose ligands are expressed therein. This also applied to chronic lymphocytic leukemia cells, where chemokine receptor expression and extent of organ infiltration were found to correlate inversely with these cells' level of p66Shc expression. p66Shc expression declined with disease progression in Eμ-TCL1 mice and could be restored by treatment with the Bruton tyrosine kinase inhibitor ibrutinib. Our results highlight p66Shc deficiency as an important factor in the progression and severity of chronic lymphocytic leukemia and underscore p66Shc expression as a relevant therapeutic target., (Copyright© 2019 Ferrata Storti Foundation.)