Publications by authors named "Michaela Kendall Bartu"

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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  • - 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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Uterine tumor resembling ovarian sex cord tumor (UTROSCT) is a rare tumor of uncertain lineage and low malignant potential. Most tumors behave in a benign manner, but a subset of UTROSCT exhibit an aggressive clinical course with recurrences and metastases. The recurrent molecular alterations in UTROSCT mostly represent gene fusions involving NCOA1-3.

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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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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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Endometrial stromal tumors are rare lesions with a diverse morphology, which may make achieving the correct diagnosis challenging in some cases. We report a case of a uterine mesenchymal tumor diagnosed as endometrial stromal nodule with a peculiar whorled morphology and GREB1::CTNNB1 fusion confirmed by transcriptome RNA sequencing. The tumor was sharply demarcated, lacked invasive growth, and had benign behavior, as the patient remained without disease recurrence 15 years later.

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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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  • 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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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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Penile squamous cell carcinoma (pSCC) is a rare tumour with a variable prognosis. More prognostic markers linked to mutational signatures and the tumour immune microenvironment are needed. A cohort made up of 165 invasive pSCC was retrospectively analysed using formalin-fixed, paraffin-embedded tumour tissue, focusing on tumour mutational burden (TMB), programmed death ligand 1 (PD-L1) expression, microsatellite instability (MSI), the number of tumour infiltrating lymphocytes (TILs) expressing cytotoxic T-lymphocyte-associated protein 4 (CTLA4), HPV status determined by p16 immunohistochemistry, and several traditional histopathological variables.

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Ovarian clear cell carcinoma (OCCC) is a subtype of ovarian carcinoma characterized by unique biological features and highly malignant characteristics including low chemosensitivity. Therefore, new therapeutic targets are needed. These could include the downstream pathways of receptor tyrosine kinases, especially the human epidermal growth factor receptor 2 (HER2).

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Preferentially expressed antigen of melanoma (PRAME) is a cancer/testis antigen selectively expressed in somatic tissues and various solid malignant tumors and is associated with poor prognostic outcome. Our research aimed to comprehensively compare its expression in a large cohort of tubo-ovarian epithelial tumors and examine its correlation with our clinico-pathologic data, as well as to assess its potential use in diagnostics and therapy.We examined 485 cases of epithelial tubo-ovarian tumors including 107 clear cell carcinomas (CCC), 52 endometroid carcinomas (EC), 103 high grade serous carcinomas (HGSC), 119 low grade serous carcinomas (LGSC)/micropapillary variant of serous borderline tumors (mSBT), and 104 cases of mucinous carcinomas (MC)/mucinous borderline tumors (MBT).

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In gynecological neoplasms, immunohistochemical (IHC) expression of p53 is generally an accurate predictor of TP53 mutation status if correctly interpreted by the pathologist. However, the literature concerning cut-offs, frequency and prognostic significance of p53 staining in ovarian mucinous tumours is limited and heterogeneous. We performed an analysis of 123 primary ovarian mucinous tumours including mucinous borderline tumours (MBT), mucinous carcinomas (MC), and tumours with equivocal features between MBT and MC.

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Three main uterine leiomyoma molecular subtypes include tumors with MED12 mutation, molecular aberrations leading to HMGA2 overexpression, and biallelic loss of FH. These aberrations are mutually exclusive and can be found in approximately 80-90% of uterine leiomyoma, in which they seem to be a driver event. Approximately 10% of uterine leiomyoma, however, does not belong to any of these categories.

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Expression of neuroendocrine (NE) markers in primary ovarian non-NE epithelial tumors has rarely been evaluated. The aim of our study was to evaluate the expression of the most widely used NE markers in these neoplasms and to determine any prognostic significance of NE marker expression. The cohort consisted of 551 primary ovarian tumors, including serous borderline tumors, low-grade serous carcinomas, high-grade serous carcinomas (HGSC), clear cell carcinomas, endometroid carcinomas, mucinous borderline tumors, and mucinous carcinomas.

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Penile squamous cell carcinoma (pSCC) is a rare malignancy with a slowly increasing incidence and variable prognosis. Regional lymph node involvement signifies poor prognosis but represents a late sign, and more prognostic markers for effective patient risk stratification are urgently needed. In this retrospective study, 152 tumour samples with formalin-fixed, paraffin-embedded tissue were analysed for traditional pathological variables, tumour budding, p53, p16, and mismatch repair proteins (MMR) immunohistochemistry.

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Background: Molecular aberrations occurring in primary ovarian clear cell carcinoma (OCCC) can be of diagnostic, predictive, and prognostic significance. However, a complex molecular study including genomic and transcriptomic analysis of large number of OCCC has been lacking.

Methods: 113 pathologically confirmed primary OCCCs were analyzed using capture DNA NGS (100 cases; 727 solid cancer related genes) and RNA-Seq (105 cases; 147 genes) in order to describe spectra and frequency of genomic and transcriptomic alterations, as well as their prognostic and predictive significance.

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Testing of microsatellite instability is not only used as a triage for possible Lynch syndrome, but also to predict immunotherapy treatment response. The aim of this study was to assess the frequency of mismatch repair deficiency (MMR-D)/microsatellite instability (MSI) in 400 cases of non-endometrioid ovarian tumors (high-grade serous, low-grade serous, mucinous and clear cell), to compare different methodological approaches of testing, and to assess the optimal approach for next generation sequencing (NGS) MSI testing. For all tumors, we evaluated immunohistochemical (IHC) expression of MMR proteins and assessed microsatellite markers by PCR-based method.

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Background: We examined a large cohort of serous tubo-ovarian tumors with 26 immunohistochemical markers, with the aim to assess their value for differential diagnosis and prognosis.

Methods: Immunohistochemical analyses with 26 immunomarkers were performed on 250 primary tubo-ovarian tumors including 114 high grade serous carcinomas (HGSC), 97 low grade serous carcinomas (LGSC), and 39 serous borderline tumors (micropapillary variant, mSBT). The associations of overall positivity with clinicopathological characteristics were evaluated using the chi-squared test or Fisher's Exact test.

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Background: IMP2 and IMP3 are mRNA binding proteins involved in carcinogenesis. We examined a large cohort of ovarian tumors with the aim to assess the value of IMP2 and IMP3 for differential diagnosis, and to assess their prognostic significance.

Methods: Immunohistochemical analyses with antibodies against IMP2 and IMP3 were performed on 554 primary ovarian tumors including 114 high grade serous carcinomas, 100 low grade serous carcinomas, 124 clear cell carcinomas, 54 endometrioid carcinomas, 34 mucinous carcinomas, 75 mucinous borderline tumors, and 41 serous borderline tumors (micropapillary variant).

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Article Synopsis
  • Clear cell (hemangioblastoma-like) stromal tumor of the lung (CCSTL) is a rare type of lung tumor, and recent findings link it to the YAP1-TFE3 gene fusion.
  • A case study featured a 57-year-old male with a 45 mm lung nodule, showing specific microscopic and immunohistochemical characteristics.
  • The study's results reinforce the idea that the YAP1-TFE3 fusion is a typical feature of CCSTL, potentially helping in its classification and understanding.
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