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The subclassification of diffuse large B-cell lymphoma (DLBCL) into germinal center B-cell-like (GCB) and activated B-cell-like (ABC) subtypes has become mandatory in the 2017 update of the WHO classification of lymphoid neoplasms and will continue to be used in the WHO 5\(^{th}\) edition. The RNA-based Lymph2Cx assay has been validated as a reliable surrogate of high-throughput gene expression profiling assays for distinguishing between GCB and ABC DLBCL and provides reliable results from formalin-fixed, paraffin-embedded (FFPE) material. This test has been previously used in clinical trials, but experience from real-world routine application is rare. We routinely applied the Lymph2Cx assay to day-to-day diagnostics on a series of 147 aggressive B-cell lymphoma cases and correlated our results with the immunohistochemical subclassification using the Hans algorithm and fluorescence in situ hybridization findings using break-apart probes for MYC, BCL2, and BCL6. The routine use of the Lymph2Cx assay had a high technical success rate (94.6%) with a low rate of failure due to poor material and/or RNA quality. The Lymph2Cx assay was discordant with the Hans algorithm in 18% (23 of 128 cases). Discordant cases were mainly classified as GCB by the Hans algorithm and as ABC by Lymph2Cx (n = 11, 8.6%). Only 5 cases (3.9%) were classified as non-GCB by the Hans algorithm and as GCB by Lymph2Cx. Additionally, 5.5% of cases (n = 7) were left unclassified by Lymph2Cx, whereas they were defined as GCB (n = 4) or non-GCB (n = 3) by the Hans algorithm. Our data support the routine applicability of the Lymph2Cx assay.
Background
Panniculitis-like T-cell lymphoma is an uncommon type of non-Hodgkin lymphoma, occurring usually in the form of nodules within the subcutaneous fat tissue of the extremities or trunk. In the literature, subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is described as a distinct type of T-cell lymphoma with a variable clinical behavior, depending on molecular phenotype of T-cell receptor (TCR) and on the presence or absence of hemophagocytic syndrome.
Case presentation
We present a bioptic and autoptic case of a 65-years old Caucasian man with panniculitic T-cell lymphoma with morphological and immunohistochemical features of SPTCL, limited to the retroperitoneal and mesenteric mass, i.e. without any cutaneous involvement, and associated with severe hemophagocytic lymphohistiocytosis.
Conclusion
A panniculitic T-cell lymphoma with morphological and molecular features of SPTCL, which is limited to mesentery, i.e. does not involve subcutaneous fat, seems to be exceedingly rare.
Routine coronal paraffin-sections through the dorsal frontal and parieto-occipital cortex of a total of sixty cases with divergent causes of death were immunohistochemically (IHC) stained with an antibody against TMEM119. Samples of cerebrospinal fluid (CSF) of the same cases were collected by suboccipital needle-puncture, subjected to centrifugation and processed as cytospin preparations stained with TMEM119. Both, cytospin preparations and sections were subjected to computer-assisted density measurements. The density of microglial TMEM119-positive cortical profiles correlated with that of cytospin results and with the density of TMEM119-positive microglial profiles in the medullary layer. There was no statistically significant correlation between the density of medullary TMEM119-positive profiles and the cytospin data. Cortical microglial cells were primarily encountered in supragranular layers I, II, and IIIa and in infragranular layers V and VI, the region of U-fibers and in circumscribed foci or spread in a diffuse manner and high density over the white matter. We have evidence that cortical microglia directly migrate into CSF without using the glympathic pathway. Microglia in the medullary layer shows a strong affinity to the adventitia of deep vessels in the myelin layer. Selected rapidly fatal cases including myocardial infarcts and drowning let us conclude that microglia in cortex and myelin layer can react rapidly and its reaction and migration is subject to pre-existing external and internal factors. Cytospin preparations proved to be a simple tool to analyze and assess complex changes in the CNS after rapid fatal damage. There is no statistically significant correlation between cytospin and postmortem interval. Therefore, the quantitative analyses of postmortem cytospins obviously reflect the neuropathology of the complete central nervous system. Cytospins provide forensic pathologists a rather simple and easy to perform method for the global assessment of CNS affliction.
Hyper-IgM syndrome type 2 (HIGM2) is a B cell intrinsic primary immunodeficiency caused by mutations in AICDA encoding activation-induced cytidine deaminase (AID) which impair immunoglobulin class switch recombination (CSR) and somatic hypermutation (SHM). Whereas autosomal-recessive AID-deficiency (AR-AID) affects both CSR and SHM, the autosomal-dominant form (AD-AID) due to C-terminal heterozygous variants completely abolishes CSR but only partially affects SHM. AR-AID patients display enhanced germinal center (GC) reactions and autoimmune manifestations, which are not present in AD-AID, suggesting that SHM but not CSR regulates GC reactions and peripheral B cell tolerance. Herein, we describe two siblings with HIGM2 due to a novel homozygous AICDA mutation (c.428-1G > T) which disrupts the splice acceptor site of exon 4 and results in the sole expression of a truncated AID variant that lacks 10 highly conserved amino acids encoded by exon 4 (AID-ΔE4a). AID-ΔE4a patients suffered from defective CSR and enhanced GC reactions and were therefore indistinguishable from other AR-AID patients. However, the AID-ΔE4a variant only partially affected SHM as observed in AD-AID patients. In addition, AID-ΔE4a but not AD-AID patients revealed impaired targeting of mutational hotspot motives and distorted mutational patterns. Hence, qualitative defects in AID function and altered SHM rather than global decreased SHM activity may account for the disease phenotype in these patients.
Molecular-based subclassifications of breast cancer are important for identifying treatment options and stratifying the prognosis in breast cancer. This study aimed to assess the prognosis relative to disease-free survival (DFS) and overall survival (OS) in patients with triple-negative breast cancer (TNBC) and other subtypes, using a biomarker panel including cytokeratin 5 (CK5), cluster of differentiation 117 (CD117), and epidermal growth factor receptor (EGFR). This cohort–case study included histologically confirmed breast carcinomas as cohort arm. From a total of 894 patients, 572 patients with early breast cancer, sufficient clinical data, and archived tumor tissue were included. Using the immunohistochemical markers CK5, CD117, and EGFR, two subgroups were formed: one with all three biomarkers negative (TBN) and one with at least one of those three biomarkers positive (non-TBN). There were significant differences between the two biomarker subgroups (TBN versus non-TBN) in TNBC for DFS (p = 0.04) and OS (p = 0.02), with higher survival rates (DFS and OS) in the non-TBN subgroup. In this study, we found the non-TBN subgroup of TNBC lesions with at least one positive biomarker of CK5, CD117, and/or EGFR, to be associated with longer DFS and OS.
Due to the wide variety of benign and malignant salivary gland tumors, classification and malignant behavior determination based on histomorphological criteria can be difficult and sometimes impossible. Spectroscopical procedures can acquire molecular biological information without destroying the tissue within the measurement processes. Since several tissue preparation procedures exist, our study investigated the impact of these preparations on the chemical composition of healthy and tumorous salivary gland tissue by Fourier-transform infrared (FTIR) microspectroscopy. Sequential tissue cross-sections were prepared from native, formalin-fixed and formalin-fixed paraffin-embedded (FFPE) tissue and analyzed. The FFPE cross-sections were dewaxed and remeasured. By using principal component analysis (PCA) combined with a discriminant analysis (DA), robust models for the distinction of sample preparations were built individually for each parotid tissue type. As a result, the PCA-DA model evaluation showed a high similarity between native and formalin-fixed tissues based on their chemical composition. Thus, formalin-fixed tissues are highly representative of the native samples and facilitate a transfer from scientific laboratory analysis into the clinical routine due to their robust nature. Furthermore, the dewaxing of the cross-sections entails the loss of molecular information. Our study successfully demonstrated how FTIR microspectroscopy can be used as a powerful tool within existing clinical workflows.
The metastatic suppressor BRMS1 interacts with critical steps of the metastatic cascade in many cancer entities. As gliomas rarely metastasize, BRMS1 has mainly been neglected in glioma research. However, its interaction partners, such as NFκB, VEGF, or MMPs, are old acquaintances in neurooncology. The steps regulated by BRMS1, such as invasion, migration, and apoptosis, are commonly dysregulated in gliomas. Therefore, BRMS1 shows potential as a regulator of glioma behavior. By bioinformatic analysis, in addition to our cohort of 118 specimens, we determined BRMS1 mRNA and protein expression as well as its correlation with the clinical course in astrocytomas IDH mutant, CNS WHO grade 2/3, and glioblastoma IDH wild-type, CNS WHO grade 4. Interestingly, we found BRMS1 protein expression to be significantly decreased in the aforementioned gliomas, while BRMS1 mRNA appeared to be overexpressed throughout. This dysregulation was independent of patients’ characteristics or survival. The protein and mRNA expression differences cannot be finally explained at this stage. However, they suggest a post-transcriptional dysregulation that has been previously described in other cancer entities. Our analyses present the first data on BRMS1 expression in gliomas that can provide a starting point for further investigations.
While glioblastoma (GBM) is still challenging to treat, novel immunotherapeutic approaches have shown promising effects in preclinical settings. However, their clinical breakthrough is hampered by complex interactions of GBM with the tumor microenvironment (TME). Here, we present an analysis of TME composition in a patient-derived organoid model (PDO) as well as in organotypic slice cultures (OSC). To obtain a more realistic model for immunotherapeutic testing, we introduce an enhanced PDO model. We manufactured PDOs and OSCs from fresh tissue of GBM patients and analyzed the TME. Enhanced PDOs (ePDOs) were obtained via co-culture with PBMCs (peripheral blood mononuclear cells) and compared to normal PDOs (nPDOs) and PT (primary tissue). At first, we showed that TME was not sustained in PDOs after a short time of culture. In contrast, TME was largely maintained in OSCs. Unfortunately, OSCs can only be cultured for up to 9 days. Thus, we enhanced the TME in PDOs by co-culturing PDOs and PBMCs from healthy donors. These cellular TME patterns could be preserved until day 21. The ePDO approach could mirror the interaction of GBM, TME and immunotherapeutic agents and may consequently represent a realistic model for individual immunotherapeutic drug testing in the future.
Purpose
Therapeutic options for breast cancer (BC) treatment are constantly evolving. The Human Epidermal Growth Factor 2 (HER2)-low BC entity is a new subgroup, representing about 55% of all BC patients. New antibody–drug conjugates demonstrated promising results for this BC subgroup. Currently, there is limited information about the conversion of HER2 subtypes between primary tumor and recurrent disease.
Methods
This retrospective study included women with BC at the University Medical Centre Wuerzburg from 1998 to 2021. Data were retrieved from patients' records. HER2 evolution from primary diagnosis to the first relapse and the development of secondary metastases was investigated.
Results
In the HR-positive subgroup without HER2 overexpression, HER2-low expression in primary BC was 56.7 vs. 14.6% in the triple-negative subgroup (p < 0.000). In the cohort of the first relapse, HER2-low represented 64.1% of HR-positive vs. 48.2% of the triple-negative cohort (p = 0.03). In patients with secondary metastases, HER2-low was 75.6% vs. 50% in the triple negative subgroup (p = 0.10). The subgroup of HER2-positive breast cancer patients numerically increased in the course of disease; the HER2-negative overall cohort decreased. A loss of HER2 expression from primary BC to the first relapse correlated with a better OS (p = 0.018). No clinicopathological or therapeutic features could be identified as potential risk factors for HER2 conversion.
Conclusion
HER2 expression is rising during the progression of BC disease. In view of upcoming therapeutical options, the re-analysis of newly developed metastasis will become increasingly important.
„Black esophagus“ oder „akute Ösophagusnekrose“ (AÖN) ist eine seltene Erkrankung, die sich makroskopisch durch eine zirkumferente Schwarzverfärbung der Ösophagusmukosa mit abruptem Ende am gastroösophagealen Übergang auszeichnet. Die genaue Pathogenese ist unbekannt; es werden multifaktorielle Einflüsse wie z. B. Säurereflux, Ischämie und verringerte Schutzmechanismen der Mukosa als mögliche Ursachen diskutiert.
Vorgestellt werden 2 Obduktionsfälle, die typische Befunde einer AÖN aufwiesen. Zusätzlich hatten Fall 1 eine Candida-Infektion und Fall 2 eine Appendizitis, sodass eine infektiöse Genese in beiden Fällen eine Rolle gespielt haben könnte.
In der vorliegenden Arbeit wurde das Vorkommen neu erworbener N-Glykosylierungsmotive in t(14;18)-positiven und -negativen FL der lokalisierten (FL I/II) und fortgeschrittenen Stadien (FL III/IV), sowie zum Zeitpunkt der Primärdiagnose und des Rezidivs untersucht. Dabei wurde der jeweilige Haupttumorklon mit Hilfe von „Next Generation Sequencing“ und unter Verwendung des „LymphoTrack® Assays“ in einer Serie von 68 kryoasservierten FL identifiziert 36 t(14;18)-negative und 32 t(14;18)-positive FL. Die Frequenz neu erworbener N-Glykosylierungsmotive unterschied sich signifikant zwischen t(14;18)-positiven und -negativen PD/R-FL III/IV, während man zwischen t(14;18)-positiven und -negativen PD/R-FL I/II keinen Unterschied beobachten konnte. Des Weiteren zeigten t(14;18)-negative PD/R-FL I-IV im Vergleich zu t(14;18)-positiven PD/R-FL I-IV signifikant häufiger einen Zugewinn neuer N-Glykosylierungsmotive in der FR3 Region des BCL2 Gens, sowie eine vermehrte Nutzung des IGHV4-34 Keimbahngens. Interessanterweise beschränkte sich die Nutzung des IGHV4-34 Gens auf PD-FL und konnte in R-FL nicht nachgewiesen werden. Da sowohl das Vorkommen neu erworbener N-Glykosylierungsmotive in FR3 als auch die Nutzung von IGHV4-34 im Zusammenhang mit Autoimmunerkrankungen beschrieben wurden, deuten unsere Ergebnisse darauf hin, dass die Subgruppe der t(14;18)-negativen FL im pathologischen Prozess der Onkogenese mehr auf die Stimulation durch (Auto)-Antigene als durch die Stimulation des B-Zell Rezeptors mit Lektinen (DC-SIGN) angewiesen sein könnte.
(1) Background: C-X-C Motif Chemokine Receptor 4 (CXCR4) and Fibroblast Activation Protein Alpha (FAP) are promising theranostic targets. However, it is unclear whether CXCR4 and FAP positivity mark distinct microenvironments, especially in solid tumors. (2) Methods: Using Random Forest (RF) analysis, we searched for entity-independent mRNA and microRNA signatures related to CXCR4 and FAP overexpression in our pan-cancer cohort from The Cancer Genome Atlas (TCGA) database — representing n = 9242 specimens from 29 tumor entities. CXCR4- and FAP-positive samples were assessed via StringDB cluster analysis, EnrichR, Metascape, and Gene Set Enrichment Analysis (GSEA). Findings were validated via correlation analyses in n = 1541 tumor samples. TIMER2.0 analyzed the association of CXCR4 / FAP expression and infiltration levels of immune-related cells. (3) Results: We identified entity-independent CXCR4 and FAP gene signatures representative for the majority of solid cancers. While CXCR4 positivity marked an immune-related microenvironment, FAP overexpression highlighted an angiogenesis-associated niche. TIMER2.0 analysis confirmed characteristic infiltration levels of CD8+ cells for CXCR4-positive tumors and endothelial cells for FAP-positive tumors. (4) Conclusions: CXCR4- and FAP-directed PET imaging could provide a non-invasive decision aid for entity-agnostic treatment of microenvironment in solid malignancies. Moreover, this machine learning workflow can easily be transferred towards other theranostic targets.
Allogenic hematopoietic stem cell transplantation (allo-HCT) is a curative therapy for the treatment of malignant and non-malignant bone marrow diseases. The major complication of this treatment is a highly inflammatory reaction known as Graft-versus-Host Disease (GvHD). Cyclosporin A (CsA) and tacrolimus are used to treat GvHD which limits inflammation but also interferes with the anticipated Graft-versus-Leukemia (GvL) effect. These drugs repress conventional T cells (Tcon) along with regulatory T cells (Treg), which are important for both limiting GvHD and supporting GvL. Both of these drugs inhibit calcineurin (CN), which dephosphorylates and activates the nuclear factor of activated T-cells (NFAT) family of transcription factors. Here, we make use of our Cd4cre.Cas9+ mice and developed a highly efficient non-viral CRISPR/Cas9 gene editing method by gRNA-only nucleofection. Utilizing this technique, we demonstrated that unstimulated mouse T cells upon NFATc1 or NFATc2 ablation ameliorated GvHD in a major mismatch mouse model. However, in vitro pre-stimulated mouse T cells could not achieve long-term protection from GvHD upon NFAT single-deficiency. This highlights the necessity of gene editing and transferring unstimulated human T cells during allo-HCT. Indeed, we established a highly efficient ribonucleoprotein (RNP)-mediated CRISPR/Cas9 gene editing for NFATC1 and/or NFATC2 in pre-stimulated as well as unstimulated primary human T cells. In contrast to mouse T cells, not NFATC1 but NFATC2 deficiency in human T cells predominantly affected proinflammatory cytokine production. However, either NFAT single-knockout kept cytotoxicity of human CD3+ T cells untouched against tumor cells in vitro. Furthermore, mouse and human Treg were unaffected upon the loss of a single NFAT member. Lastly, NFATC1 or NFATC2-deficient anti-CD19 CAR T cells, generated with our non-viral ‘one-step nucleofection’ method validated our observations in mouse and human T cells. Proinflammatory cytokine production was majorly dependent on NFATC2 expression, whereas, in vitro cytotoxicity against CD19+ tumor cells was undisturbed in the absence of either of the NFAT members. Our findings emphasize that NFAT single-deficiency in donor T cells is superior to CN-inhibitors as therapy during allo-HCT to prevent GvHD while preserving GvL in patients.
Active vitamin D (1,25(OH)2D3) is known to exert direct anti-cancer actions on various malignant tissues through binding to the vitamin D receptor (VDR). These effects have been demonstrated in breast, prostate, renal and thyroid cancers, which all have a high propensity to metastasise to bone. In addition, there is evidence that vitamin D catabolism via 24-hydroxylase (CYP24A1) is altered in tumour cells, thus, reducing local active vitamin D levels in cancer cells. The aim of this study was to assess VDR and CYP24A1 expression in various types of bone metastases by using immunohistochemistry. Overall, a high total VDR protein expression was detected in 59% of cases (39/66). There was a non-significant trend of high-grade tumours towards the low nuclear VDR expression (p = 0.07). Notably, patients with further distant metastases had a reduced nuclear VDR expression (p = 0.03). Furthermore, a high CYP24A1 expression was detected in 59% (39/66) of bone metastases. There was a significant positive correlation between nuclear VDR and CYP24A1 expression (p = 0.001). Collectively, the VDR and CYP24A1 were widely expressed in a multitude of bone metastases, pointing to a potential role of vitamin D signalling in cancer progression. This is of high clinical relevance, as vitamin D deficiency is frequent in patients with bone metastases.
Machine-Learning-Based Identification of Tumor Entities, Tumor Subgroups, and Therapy Options
(2023)
Molecular genetic analyses, such as mutation analyses, are becoming increasingly important in the tumor field, especially in the context of therapy stratification. The identification of the underlying tumor entity is crucial, but can sometimes be difficult, for example in the case of metastases or the so-called Cancer of Unknown Primary (CUP) syndrome. In recent years, methylome and transcriptome utilizing machine learning (ML) approaches have been developed to enable fast and reliable tumor and tumor subtype identification. However, so far only methylome analysis have become widely used in routine diagnostics.
The present work addresses the utility of publicly available RNA-sequencing data to determine the underlying tumor entity, possible subgroups, and potential therapy options. Identification of these by ML - in particular random forest (RF) models - was the first task. The results with test accuracies of up to 99% provided new, previously unknown insights into the trained models and the corresponding entity prediction. Reducing the input data to the top 100 mRNA transcripts resulted in a minimal loss of prediction quality and could potentially enable application in clinical or real-world settings.
By introducing the ratios of these top 100 genes to each other as a new database for RF models, a novel method was developed enabling the use of trained RF models on data from other sources.
Further analysis of the transcriptomic differences of metastatic samples by visual clustering showed that there were no differences specific for the site of metastasis. Similarly, no distinct clusters were detectable when investigating primary tumors and metastases of cutaneous skin melanoma (SKCM).
Subsequently, more than half of the validation datasets had a prediction accuracy of at least 80%, with many datasets even achieving a prediction accuracy of – or close to – 100%.
To investigate the applicability of the used methods for subgroup identification, the TCGA-KIPAN dataset, consisting of the three major kidney cancer subgroups, was used. The results revealed a new, previously unknown subgroup consisting of all histopathological groups with clinically relevant characteristics, such as significantly different survival. Based on significant differences in gene expression, potential therapeutic options of the identified subgroup could be proposed.
Concludingly, in exploring the potential applicability of RNA-sequencing data as a basis for therapy prediction, it was shown that this type of data is suitable to predict entities as well as subgroups with high accuracy. Clinical relevance was also demonstrated for a novel subgroup in renal cell carcinoma. The reduction of the number of genes required for entity prediction to 100 genes, enables panel sequencing and thus demonstrates potential applicability in a real-life setting.
Background: Primary cutaneous follicular B-cell lymphoma (PCFBCL) represents an indolent subtype of Non-Hodgkin’s lymphomas, being clinically characterized by slowly growing tumors of the skin and common cutaneous relapses, while only exhibiting a low propensity for systemic dissemination or fatal outcome. Up to now, only few studies have investigated underlying molecular alterations of PCFBCL with respect to somatic mutations. Objectives: Our aim was to gain deeper insight into the pathogenesis of PCFBCL and to delineate discriminatory molecular features of this lymphoma subtype. Methods: We performed hybridization-based panel sequencing of 40 lymphoma-associated genes of 10 cases of well-characterized PCFBCL. In addition, we included two further ambiguous cases of atypical B-cell-rich lymphoid infiltrate/B-cell lymphoma of the skin for which definite subtype attribution had not been possible by routine investigations. Results: In 10 out of 12 analyzed cases, we identified genetic alterations within 15 of the selected 40 target genes. The most frequently detected alterations in PCFBCL affected the TNFRSF14, CREBBP, STAT6 and TP53 genes. Our analysis unrevealed novel mutations of the BCL2 gene in PCFBCL. All patients exhibited an indolent clinical course. Both the included arbitrary cases of atypical B-cell-rich cutaneous infiltrates showed somatic mutations within the FAS gene. As these mutations have previously been designated as subtype-specific recurrent alterations in primary cutaneous marginal zone lymphoma (PCMZL), we finally favored the diagnosis of PCMZL in these two cases based on these molecular findings. Conclusions: To conclude, our molecular data support that PCFBCL shows distinct somatic mutations which may aid to differentiate PCFBCL from pseudo-lymphoma as well as from other indolent and aggressive cutaneous B-cell lymphomas. While the detected genetic alterations of PCFBCL did not turn out to harbor any prognostic value in our cohort, our molecular data may add adjunctive discriminatory features for diagnostic purposes on a molecular level.
(1) Background: molecular tumor boards (MTBs) are crucial instruments for discussing and allocating targeted therapies to suitable cancer patients based on genetic findings. Currently, limited evidence is available regarding the regional impact and the outreach component of MTBs; (2) Methods: we analyzed MTB patient data from four neighboring Bavarian tertiary care oncology centers in Würzburg, Erlangen, Regensburg, and Augsburg, together constituting the WERA Alliance. Absolute patient numbers and regional distribution across the WERA-wide catchment area were weighted with local population densities; (3) Results: the highest MTB patient numbers were found close to the four cancer centers. However, peaks in absolute patient numbers were also detected in more distant and rural areas. Moreover, weighting absolute numbers with local population density allowed for identifying so-called white spots—regions within our catchment that were relatively underrepresented in WERA MTBs; (4) Conclusions: investigating patient data from four neighboring cancer centers, we comprehensively assessed the regional impact of our MTBs. The results confirmed the success of existing collaborative structures with our regional partners. Additionally, our results help identifying potential white spots in providing precision oncology and help establishing a joint WERA-wide outreach strategy.
NFATc3 in der akuten GvHD
(2023)
Bei Leukämien, Lymphomen und dem Multiplen Myelom stellt die allogene hämatopoetische Stammzelltransplantation (allo-HCT) oft die letzte kurative Therapieoption dar. Spender-T-Zellen (v.a. CD8+-T-Zellen), die im Transplantat enthalten sind, erkennen nach Chemo-/Strahlentherapie verbliebene Reste des entarteten Empfängergewebes, eradizieren dieses und verhindern somit ein Tumorrezidiv (Graft-versus-Leukämie Reaktion/GvL). Häufig attackieren Spender-T-Zellen (v.a. CD4+-Th1-Zellen) aber auch nicht-malignes Gewebe (z.B. Haut, Leber und Darm), was bis zum Tod des Patienten führen kann (Graft-versus-Host Disease/GvHD). Calcineurin-Inhibitoren wie Cyclosporin A (CsA) und Tacrolimus, die oft schon prophylaktisch verabreicht werden, verhindern über eine unselektive Inhibition aller Mitglieder der NFAT-Transkriptionsfaktorfamilie (Nuclear factor of activated T-cells) die Aktivierung der Spender-T-Zellen. Es folgt eine klinische Besserung der GvHD-Symptomatik, während jedoch der GvL-Effekt ebenfalls supprimiert wird. Bisherige Untersuchungen unserer Arbeitsgruppe am Mausmodell hatten gezeigt, dass die selektive Inhibition eines NFAT-Familienmitgliedes (NFATc1 oder NFATc2) in den Donor-T-Zellen zu einer signifikanten Besserung der aGvHD bei jedoch erhaltener GvL führt. Es wurde nun der Einfluss des dritten, in Lymphozyten exprimierten NFAT-Mitglieds NFATc3 im Kontext der aGvHD untersucht.
Zur Basisanalyse der neu kreierten Nfatc3fl/fl.Cd4cre- und Nfatc1fl/fl.Nfatc3fl/fl.Cd4cre-Mauslinien erfolgten durchflusszytometrische und Western-Blot-Analysen. Anschließend wurden In-vivo-Untersuchungen unter Verwendung eines etablierten major-mismatch-aGvHD-Modells (H-2b→H-2d) durchgeführt.
Es konnte gezeigt werden, dass durch eine NFATc3- (+/- NFATc1-) Defizienz direkt ex vivo die CD4+/CD8+-Ratio durch Abnahme der CD4+- hin zu den CD8+-T-Zellen verschoben wird. Auch zeigte sich in den entsprechenden Genotypen eine Abnahme der naiven- und dafür vice versa eine Zunahme der Effektor-T-Zellen. In den wiederholt durchgeführten aGvHD-Versuchen zeigte sich in vivo als Korrelat der (ebenfalls erneut nachgewiesenen) Abnahme des CD4+/CD8+-Quotienten in den Zielorganen eine geringere Expansion der NFAT-defizienten als der wildtypischen T-Zellen. Leider spiegelte sich dies nicht in dem clinical score zur Quantifizierung der aGvHD-Symptomatik wider. Auch das Körpergewicht der Versuchsgruppe nahm rapide ab. Ursächlich hierfür ist – als Korrelat zur direkt ex vivo nachgewiesenen Aktivierungsneigung – ein vermehrter Th1-Shift der NFATc3 (+/-NFATc1-) defizienten T-Zellen.
Eine Inhibierung von NFATc3 – im Gegensatz zu NFATc1 und NFATc2 – ist demzufolge kein sinnvoller Ansatzpunkt für eine mögliche, zielgerichtetere aGvHD-Therapie. Der positive Effekt der reduzierten Proliferationsneigung der NFATc3-defizienten Lymphozyten wird durch deren vermehrte Aktivierungsneigung mit erhöhter Sekretion von pro-inflammatorischen Zytokinen zunichte gemacht.
Glioblastoma leads to a fatal course within two years in more than two thirds of patients. An essential cornerstone of therapy is chemotherapy with temozolomide (TMZ). The effect of TMZ is counteracted by the cellular repair enzyme O\(^6\)-methylguanine-DNA methyltransferase (MGMT). The MGMT promoter methylation, the main regulator of MGMT expression, can change from primary tumor to recurrence, and TMZ may play a significant role in this process. To identify the potential mechanisms involved, three primary stem-like cell lines (one astrocytoma with the mutation of the isocitrate dehydrogenase (IDH), CNS WHO grade 4 (HGA)), and two glioblastoma (IDH-wildtype, CNS WHO grade 4) were treated with TMZ. The MGMT promoter methylation, migration, proliferation, and TMZ-response of the tumor cells were examined at different time points. The strong effects of TMZ treatment on the MGMT methylated cells were observed. Furthermore, TMZ led to a loss of the MGMT promoter hypermethylation and induced migratory rather than proliferative behavior. Cells with the unmethylated MGMT promoter showed more aggressive behavior after treatment, while HGA cells reacted heterogenously. Our study provides further evidence to consider the potential adverse effects of TMZ chemotherapy and a rationale for investigating potential relationships between TMZ treatment and change in the MGMT promoter methylation during relapse.
In der modernen Tumortherapie sind Checkpoint-Inhibitoren ein fester Bestandteil. Die Oberflächenproteine PD-L1 und PD-1 stellen die Angriffspunkte dieser spezifischen Therapie dar. Die Datenlage hinsichtlich PD-L1 in HNSCC ist sehr heterogen. Diese Arbeit beschäftigte sich daher mit der Expression von PD-L1 und PD-1 in einem
Kollektiv von 118 Plattenepithelkarzinomen in Larynx und Hypopharynx und einer prognostischen Aussagekraft hinsichtlich mehrerer histopathologischer und epidemiologischer Faktoren. Außerdem wurde ein möglicher Zusammenhang zwischen der Expression von PD-L1, PD-1 und CD5 als T-Zell-Marker in besagtem Kollektiv untersucht. Die IHC-Färbungen wurden lichtmikroskopisch an tissue micro arrays untersucht. Für
die Auswertung von PD-L1 wurde der bereits etablierte Cologne-Score verwendet, welcher zum einen zunächst erweitert und anschließend zwecks einer fundierten statistischen Auswertung ergänzend modifiziert wurde. Für CD5 und PD-1 wurden eigene Cut-Off-Werte generiert.
48 % der Fälle waren PD-L1+, die Spannweite im Literaturvergleich schwankt zwischen 30 – 90 %. PD-1+ waren insgesamt 31% der Fälle, auch hier zeigen sich deutliche Abweichungen zu den vorliegenden Publikationen. Hinsichtlich der prognostischen Aussagekraft konnte ein signifikanter Zusammenhang zwischen dem T-Stadium und der PD-L1-Expression aufgezeigt werden. Ob dies Einfluss auf mögliche
Behandlungsstrategien hat, bleibt Gegenstand weiterer Forschung. Auch im Literaturvergleich finden sich wiederholt signifikante prognostische Zusammenhänge, jedoch beziehen sich diese auf differente Faktoren. Ursächlich dafür sind aller Wahrscheinlichkeit nach Diskrepanzen in der PD-L1-Expression sowie deren Schwankungen durch äußere Einflüsse und nicht standardisierte Testverfahren. Es zeigten sich weiterhin Korrelationen zwischen den Markern, welche sich abschließend nicht alle gänzlich herleiten lassen.
Zusammenfassend könnten einheitliche Testverfahren die Datenlage zu PD-L1 und PD-1 homogenisieren, auch mögliche Vortherapien sollten dementsprechend berücksichtigt werden. Allerdings erscheint die prognostische Aussagekraft von PD-L1 und auch von PD-1 insgesamt aufgrund der inkonstanten Expression hochgradig eingeschränkt, sodass
sich in Zukunft vermehrt auf andere Marker konzentriert werden sollte.