Publications by authors named "Matej R"

Background: Juvenile granulosa cell tumor (JGCT) of the ovary is a rare tumor with distinct clinicopathological and hormonal features primarily affecting young women and children. We conducted a complex clinicopathological, immunohistochemical, and molecular analysis of five cases of JGCT.

Methods: The immunohistochemical examination was performed with 32 markers, including markers that have not been previously investigated.

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Penile squamous cell carcinoma (pSCC) represents an uncommon malignancy characterized by stagnant mortality, psychosexual distress, and a highly variable prognosis. Currently, the WHO distinguishes between human papillomavirus (HPV) related and HPV independent pSCC. Recently, there has been an evolving line of research documenting the enrichment of HPV-independent pSCC with a high tumor mutational burden (TMB) and programmed death ligand-1 (PD-L1) expression, as well as clusters of genes associated with HPV status.

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Article Synopsis
  • - Uterine sarcomas with KAT6B/A::KANSL1 fusion are a new type of tumor that show a mix of traits from low-grade endometrial stromal sarcomas and smooth muscle tumors, which can confuse initial diagnoses.
  • - A study involving 9 such cases found common features like expression of smooth muscle and endometrial stromal markers, as well as the presence of the KAT6B/A::KANSL1 fusion in all tumors.
  • - Despite their bland appearance, these tumors can be aggressive, with some patients experiencing severe outcomes, underscoring the need for accurate recognition and diagnosis for better treatment approaches.
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  • About 95% of AGCT cases carry the FOXL2 p.C134W mutation, while TERT promoter alterations are associated with worse survival outcomes.
  • This study analyzed 183 primary and 44 recurrent AGCTs, revealing potential prognostic implications of FOXO1 mutations and confirming high rates of FOXL2 mutations, while uncovering various other genetic mutations associated with AGCT recurrence.
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  • This study analyzes 37 ovarian Sertoli-Leydig cell tumors (SLCT) with a focus on their morphology, immunohistochemistry, and molecular features, categorizing them into well, moderately, and poorly differentiated tumors.
  • High levels of sex cord markers were found, along with variable expression of other markers, and notable mutations like DICER1 (54.5%) and FOXL2 (6%) were identified, suggesting important diagnostic and predictive implications.
  • Differences in mRNA expression profiles between DICER1 and non-DICER1 tumors highlight the distinct molecular characteristics of SLCTs, indicating that well-differentiated tumors could represent a unique subtype apart from the others.
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Colorectal cancer (CRC) is a leading global cause of illness and death. There is a need for identification of better prognostic markers beyond traditional clinical variables like grade and stage. Previous research revealed that abnormal expression of cytokeratin 7 (CK7) and loss of the intestinal-specific Special AT-rich sequence-binding protein 2 (SATB2) are linked to poor CRC prognosis.

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Purpose: The purpose of this study was to assess the effectiveness of legally mandated testing for pathogenic prion proteins in corneal tissue donors in the Czech Republic, considering its impact on safety, financial, and temporal costs.

Methods: Between January 2007 and December 2023, standardized brain regions were collected from all corneal tissue donors in the Czech Republic. Tissue samples were tested for the presence of pathogenic prion proteins by the Czech Reference Laboratory for Human Prion Diseases.

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Recent studies have suggested that pathogenic variants of the gene could be a driver of alterations in some pediatric thyroid nodules, but data are still limited. The aim of this study was to detect variants in the gene in a large cohort of pediatric thyroid nodules and then correlate them with clinicopathological data, with a focus on the disease prognosis in patients with thyroid carcinoma. This retrospective cohort study consisted of 350 pediatric and young adult patients (aged 2-21 years) with thyroid nodules, from whom 275 fresh-frozen thyroid nodule samples and 92 fine-needle aspiration biopsy (FNAB) samples were collected.

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The amyloid cascade hypothesis postulates that extracellular deposits of amyloid β (Aβ) are the primary and initial cause leading to the full development of Alzheimer's disease (AD) with intracellular neurofibrillary tangles; however, the details of this mechanism have not been fully described until now. Our preliminary data, coming from our day-to-day neuropathology practice, show that the primary location of the hyperphosphorylated tau protein is in the vicinity of the cell membrane of dystrophic neurites. This observation inspired us to formulate a hypothesis that presumes an interaction between low-density lipoprotein receptor-related protein 1 (LRP1) and fibrillar aggregates of, particularly, Aβ anchored at the periphery of neuritic plaques, making internalization of the LRP1-Aβ complex infeasible and, thus, causing membrane dysfunction, leading to the tauopathy characterized by intracellular accumulation and hyperphosphorylation of the tau protein.

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Using immunohistochemistry, we examined a large cohort of 135 ovarian tumors, made up of 96 low-grade serous carcinomas (LGSCs) and 39 serous borderline tumors (micropapillary variant, mSBT), with the aim of exploring their HER2 status (overexpression). We followed with comprehensive genomic analyses on this sample set from our previous study, which revealed HER2 mutation in 5% (4/75) of LGSC and 10% (3/29) of mSBT. No cases were evaluated as HER2-positive, but 6 LGSCs and 1 mSBT were scored as HER2 1+, and 2 LGSCs and 1 mSBT showed the so-called HER2 "ultra-low" phenotype.

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Aim: Transbronchial cryobiopsies are increasingly used for the diagnosis of interstitial lung disease (ILD), but there is a lack of published information on the features of specific ILD in cryobiopsies. Here we attempt to provide pathological guidelines for separating usual interstitial pneumonia (UIP) of idiopathic pulmonary fibrosis (IPF), fibrotic hypersensitivity pneumonitis (FHP) and connective tissue disease-associated ILD (CTD-ILD) in cryobiopsies.

Methods: We examined 120 cryobiopsies from patients with multidisciplinary discussion (MDD)-established CTD-ILD and compared them to a prior series of 121 biopsies from patients with MDD-established IPF or FHP.

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Background: Stathmin, a cytosolic microtubule-destabilizing phosphoprotein involved in the regulation of mitosis, is widely expressed in various malignancies and acts as an adverse prognostic factor. Our research analyzed its immunohistochemical expression on a large cohort of ovarian sex cord-stromal tumors, evaluating its potential utility in differential diagnosis, prognosis, and therapeutic application.

Methods: We examined 390 cases of ovarian sex cord-stromal tumors including 281 adult granulosa cell tumors (AGCT), 5 juvenile granulosa cell tumors (JGCT), 33 Sertoli-Leydig cell tumors (SLCT), 50 fibromas/thecomas (F/T), 11 Leydig cell tumors/steroid cell tumors (LCT/SterCT), 5 sex-cord stromal tumors NOS (SCST-NOS), 3 Sertoli cell tumors (SCT), and 2 sclerosing stromal tumors (ScST).

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The current knowledge about the immunohistochemical features of adult granulosa cell tumor (AGCT) is mostly limited to the "traditional" immunohistochemical markers of sex cord differentiation, such as inhibin, calretinin, FOXL2, SF1, and CD99. Knowledge about the immunohistochemical markers possibly used for predictive purpose is limited. In our study, we focused on the immunohistochemical examination of 290 cases of AGCT classified based on strict diagnostic criteria, including molecular testing.

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Mouse neuronal CAD 5 cell line effectively propagates various strains of prions. Previously, we have shown that it can also be differentiated into the cells morphologically resembling neurons. Here, we demonstrate that CAD 5 cells chronically infected with prions undergo differentiation under the same conditions.

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Undifferentiated carcinoma with osteoclast-like giant cells (UCOGC) of the pancreas is a rare malignancy regarded as a subvariant of pancreatic ductal carcinoma (PDAC) characterized by variable prognosis. UCOGC shows a strikingly similar spectrum of oncogenic DNA mutations to PDAC. In the current work, we analyzed the landscape of somatic mutations in a set of 13 UCOGC cases via next-generation sequencing (NGS).

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Real-time quaking-induced conversion assay (RT-QuIC) exploits templating activity of pathogenic prion protein for ultrasensitive detection of prions. We have utilized second generation RT-QuIC assay to analyze matching post-mortem cerebrospinal fluid and skin samples of 38 prion disease patients and of 30 deceased neurological controls. The analysis of cerebrospinal fluid samples led to 100% sensitivity and 100% specificity, but some samples had to be diluted before the analysis to alleviate the effect of present RT-QuIC inhibitors.

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Article Synopsis
  • Non-smooth muscle uterine sarcomas include various rare types, with low-grade endometrial stromal sarcoma being the most common, while the understanding of these tumors is evolving due to insights into their molecular changes.
  • * The review aimed to analyze different types and frequencies of genetic fusions in these tumors, highlighting overlaps in diagnosis and classification.
  • * A total of 110 fusions were found in 703 tumors, revealing challenges in interpreting molecular changes due to their rarity and the complex nature of these aberrations across different tumor types.
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Background: Thrombosis is linked to neutrophil release of neutrophil extracellular traps (NETs). NETs are proposed as a mechanism of resistance to thrombolysis. This study intends to analyze the composition of thrombi retrieved after mechanical thrombectomy, estimate the age and organization of thrombi, and evaluate associations with the use of thrombolysis, antiplatelets, and heparin.

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Aims: The objective of this study was to investigate the association and combined prognostic significance of the PD-L1, Smoothened protein and β-catenin expressions in patients with clear cell renal cell carcinoma (ccRCC).

Methods: The PD-L1, Smoothened protein and β-catenin expression were evaluated in 104 ccRCC patients. All studied tumor samples were acquired from nephrectomy specimens of primary tumors and not from biopsies or metastases.

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A 41-year-old man was admitted to hospital due to sudden loss of consciousness. A regional brain perfusion SPECT/low-dose CT showed abnormal 99m Tc-HMPAO uptake in the right hemisphere frontotemporally without any other supratentorial or infratentorial radiotracer uptake. A neuropathological examination disclosed a middle cerebral artery aneurysm.

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Low-grade serous carcinoma (LGSC) may develop from serous borderline tumor (SBT) tissue, where the micropapillary type (mSBT) presents the highest risk for progression. The sensitivity of LGSC to standard chemotherapy is limited, so alternative therapeutic approaches, including targeted treatment, are needed. However, knowledge about the molecular landscape of LGSC and mSBT is limited.

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The heterogeneity of the glioma subtype glioblastoma multiforme (GBM) challenges effective neuropathological treatment. The reliance on in vitro studies and xenografted animal models to simulate human GBM has proven ineffective. Currently, a dearth of knowledge exists regarding the applicability of cell line biomolecules to the realm of GBM pathogenesis.

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