Endocrine Pathology最新文献

An integrative histologic and molecular classification of thyroid tumors has become clinically relevant due to the potential role in risk stratification and selection of targeted therapy. In this review, we discuss the applications of six "next-generation" immunohistochemical markers, namely BRAF V600E (clone VE1), RAS Q61R (clone SP174), pan-TRK (clone EPR 17341), ALK (clones 5A4 or D5F3), PTEN, and β-catenin in the pathologic diagnosis and molecular classification of thyroid tumors. These biomarkers allow the in situ examination of tumor tissue and assist in the diagnosis and pathologic staging by highlighting tumor border and patterns of invasion, identifying isolated tumor cells in lymph nodes, distinguishing lymph node metastasis from benign intranodal thyroid inclusions, and diagnosing multicentric thyroid carcinomas with discordant molecular drivers. Furthermore, it can identify specific thyroid neoplasms that may occur sporadically or may be associated with hereditary syndromes. The next-generation immunohistochemistry provides a novel solution to challenging issues in thyroid pathology and fast turn-around time for accurate molecular classification and further guidance of therapeutic management.

NTRK fusions are rare but recurrent driver alterations in papillary thyroid carcinoma (PTC), with therapeutic significance due to the availability of targeted TRK inhibitors. Pan-TRK immunohistochemistry (IHC) provides a practical approach for the identification of NTRK fusions; however, its application and reliability in routine pathology require further exploration. This study is aimed at evaluating the diagnostic utility of pan-TRK IHC for detecting NTRK fusions in PTC, assessing its correlation with histopathologic features, and developing a diagnostic algorithm. We analyzed 107 BRAF p.V600E-negative PTC cases using pan-TRK IHC, correlating staining patterns with molecular data and histopathologic features. RNA-based targeted sequencing confirmed gene fusions. NTRK fusion-positive tumors were enriched in distinct histopathologic features, including BRAF-like PTC with predominant follicular architecture, clear cells, and secretory-like cells. Findings such as tumor cell stratification, glomeruloid structures, and papillae with subfollicle formation (microfollicles within papillary structures) were associated with both NTRK and RET fusion-positive PTCs. Correlation of pan-TRK IHC and molecular testing results identified non-specific reactivity or false positivity in 62% of pan-TRK IHC-positive PTCs, including cases with RET fusions, BRAF fusion, or no detectable fusion. However, pan-TRK IHC with high H-scores (≥ 110) was observed exclusively in cases with NTRK fusions. For cases with lower H-scores (< 110), integrating histopathologic features improved the identification of fusion-driven PTCs. While our series further supports the limitations of pan-TRK IHC, a diagnostic algorithm that combines pan-TRK IHC H-scores and histopathologic patterns improved the triaging of NTRK molecular testing of BRAF p.V600E-negative PTCs when a stepwise approach is undertaken. This study also demonstrated that TRK protein localization may vary with tumor progression and dedifferentiation.

Neuroendocrine tumors (NET) of the lung constitute a rare entity of primary lung malignancies that often exhibit an indolent clinical course. Epigenetics-related differences have been described previously for lung NET, but the clinical significance remains unclear. In this study, we performed genome-wide methylation analysis using the Infinium MethylationEPIC BeadChip technology on FFPE tissues from lung NET treated at two academic centers. We aimed to investigate the methylation profiles of known prognostic subgroups. In total, 54 tissue samples from primary lung NET were analyzed, of which 37 were typical carcinoids (TC) and 17 atypical carcinoids (AC). Overall, 25/53 patients (47.2%) developed metastases throughout the disease course, 14/26 (53.8%) had a positive somatostatin receptor (SSTR) scan, and 7/28 patients (25.0%) had documented endocrine activity. Analysis of the DNA methylation data showed substantial differences between TC and AC samples and revealed three distinct clusters (C1-C3): C3 (n = 29) with 100% TC and 89.7% non-metastasized, C2 (n = 22) with 63.6% AC and 95.5% metastasized, and C1 with three AC samples (2/3 metastasized). In subgroup analyses, distinct methylation patterns were observed based on histology, metastases, SSTR status, and endocrine activity. In the functional gene classification, the genes affected by differential methylation were mainly involved in cell signaling. DNA methylation could potentially aid in the diagnostic process of lung NET. The differences in methylation observed with respect to clinical features like SSTR expression and endocrine activity could translate into improved management of lung NET.

Papillary thyroid carcinoma (PTC) is the most common form of well-differentiated thyroid cancer (WDTC) and generally has a favorable prognosis. However, subsets of these tumors can metastasize, leading to aggressive disease progression and poorer clinical outcomes. Radioactive iodine (RAI) therapy is routinely given in the adjuvant setting following thyroidectomy and lymph node dissection for WDTC. Nevertheless, its therapeutic efficacy is limited to tumors with high iodine avidity. Early post-surgical classification of thyroid cancers as either iodine-avid or refractory is crucial for enabling more personalized and effective treatment strategies. In this study, we aimed to identify transcriptomic determinants associated with RAI refractoriness (RAI-R) to improve prognostication. We collected clinicopathologic data and conducted RNA-seq on 36 tissue samples (18 high-avidity and 18 low-avidity), each uniquely characterized by ex vivo iodine concentration measurements taken directly from surgical specimens. Whole-transcriptomic analysis identified 63 differentially expressed genes, with six (S100A4, CRTC2, ANO1, WWTR1, DEPTOR, MT1G) showing consistent deregulation. The expression of ANO1, an established iodine transporter at the apical membrane of the thyroid follicular cells, correlated significantly with iodine avidity (r = 0.54). Validation via RT-qPCR confirmed differential expression trends. Gene ontology and pathway enrichment analyses highlighted thyroid hormone synthesis, PI3K-AKT, and MAPK signaling pathways as key regulators of RAI avidity. A refined multivariate predictive model incorporating ANO1 mRNA expression, histological subtypes, and sample type demonstrated strong predictive performance (adjusted R² = 0.55). These findings suggest ANO1 as a promising biomarker for predicting iodine avidity in thyroid cancer.

Pediatric papillary thyroid carcinoma (PPTC; under age 18 at the time of diagnosis) is relatively uncommon. There are few studies concerning the genetic background of PPTC in Asian countries. In this study, we reviewed 124 cases of PPTC from a single medical center in China. DNA-based next-generation sequencing (NGS) was performed to identify genetic alterations, with receptor tyrosine kinase (RTK) fusions further validated by RNA-based NGS. DICER1 mutations and TERT promoter mutations were detected by Sanger sequencing. We also explored the relationship between these genetic alterations and the clinicopathologic features, as well as the prognostic factors. Three recombinant plasmids expressing V5/HIS-tagged RTK fusion proteins (BEND7::ALK, DLG5::RET, CCDC30::ROS1) were constructed to investigate the in vitro effects. We found that the two most common subtypes were the classic subtype (77.4%) and the diffuse sclerosing subtype (17.7%). Hashimoto's thyroiditis was observed in 42.3% of cases, and regional lymph node metastasis was present in 82.9% of patients. The most frequent genetic alteration was the BRAF c.1799 T > A (p.V600E) mutation (63 patients, 50.8%), followed by RTK fusions (31 patients, 25.0%). A DICER1 mutation was detected in two cases, and TERT promoter mutations were not observed in any of the patients. RTK fusions were associated with the diffuse sclerosing subtype, Hashimoto's thyroiditis, and extrathyroidal extension. Adverse prognostic factors identified included RTK fusion, age under 14 years, and tumor size over 2 cm. Additionally, a significant proportion of these patients had actionable molecular alterations. Three rare kinase fusions, BEND7::ALK, DLG5::RET, and CCDC30::ROS1, were shown to induce phosphorylation of the MAPK pathway and promote cell proliferation in vitro. The specific RTK inhibitors could counteract the fusion-induced cell proliferation. Our data highlights the genetic landscape of Chinese PPTC patients, with RTK fusions being associated with aggressive clinicopathologic features. The rare fusions BEND7::ALK, DLG5::RET, and CCDC30::ROS1 may contribute to PPTC development with a BRAF-like effect.

Functioning pancreatic neuroendocrine tumors (PanNETs) represent a subset of PanNETs that cause symptoms due to hormonal activity. Insulinoma is the most common functioning PanNET type. Mutations in the alpha thalassemia/mental retardation X-linked (ATRX) and death domain-associated protein (DAXX) genes result in genomic instability. ATRX/DAXX mutations and associated alternative lengthening of telomeres (ALT) are common in non-functioning PanNETs and associated with aggressive tumor behavior. Recent reports have shown that ATRX/DAXX mutations and ALT are also present in functioning PanNETs. In this review, we summarize the literature addressing ATRX/DAXX mutations and ALT in functioning PanNETs and discuss the clinical relevance with regard to distinguishing aggressive and indolent functioning tumors. ATRX/DAXX gene mutations and/or ALT have been reported in insulinoma, glucagonoma, gastrinoma, VIPoma and calcitoninoma. In insulinoma, the presence of ATRX/DAXX mutations and ALT are associated with aggressive behavior and could therefore be used as prognostic biomarkers. Although ATRX/DAXX mutation and ALT assessment may currently not be the standard of care in routine diagnostic pathology practice, the use of DAXX/ATRX immunohistochemistry at least can be encouraged not only for non-functioning but also for functioning PanNETs.

Pancreatic neuroendocrine tumors (PanNETs) are a heterogeneous group of neoplasms that include tumors with different histomorphologic characteristics that can be correlated to sub-categories with different prognoses. In addition to the WHO grading scheme based on tumor proliferative activity, a new parameter based on the scoring of infiltration patterns at the interface of tumor and non-neoplastic parenchyma (tumor-NNP interface) has recently been proposed for PanNET categorization. Despite the known correlations, these categorizations can still be problematic due to the need for human judgment, which may involve intra- and inter-observer variability. Although there is a great need for automated systems working on quantitative metrics to reduce observer variability, there are no such systems for PanNET categorization. Addressing this gap, this study presents a computational pipeline that uses deep learning models to automatically categorize PanNETs for the first time. This pipeline proposes to quantitatively characterize PanNETs by constructing entity-graphs on the cells, and to learn the PanNET categorization using a graph neural network (GNN) trained on these graphs. Different than the previous studies, the proposed model integrates pathology domain knowledge into the GNN construction and training for the purpose of a deeper utilization of the tumor microenvironment and its architectural changes for PanNET categorization. We tested our model on 105 HE stained whole slide images of PanNET tissues. The experiments revealed that this domain knowledge integrated pipeline led to a 76.70% test set F1-score, resulting in significant improvements over its counterparts.

Merkel cell carcinoma (MCC) is diagnosed through histopathological and immunohistochemical examination of biopsies from skin or other organs. Its distinguishing features include perinuclear dot-like staining with Cytokeratin 20 (CK20) and detection of Merkel cell polyomavirus (MCPyV) using various methods. However, CK20 and MCPyV negative MCC cases have been reported at varying rates. In this single center cross-sectional study, we aimed to determine which clones are more effective in diagnosing MCC by comparing the performance of CK20 antibody clones Ks20.8 and SP33, as well as MCPyV antibody clones Ab3 and CM2B4. Fifty-four patients diagnosed with MCC were included. Among these, 42 cases were primary cutaneous, and 12 cases were nodal MCC. Fifty-two (96.3%) cases were positive with both CK20 clones, while two cases were negative. Clone SP33 stained areas of necrosis, whereas Ks20.8 showed no aberrant staining. MCPyV was detected in 44 cases (81.5%) using clone Ab3 and 39 cases (72.2%) using clone CM2B4. Staining with MCPyV clone Ab3 was diffuse and strong in most cases, while approximately 30% of CM2B4-positive cases exhibited low percentages and/or weak staining, complicating the evaluation. The two CK20-negative cases were also negative with both MCPyV clones. Our data demonstrated that CK20 clone Ks20.8 may be preferred for MCC diagnosis due to its consistent performance and lack of aberrant staining. Similarly, MCPyV clone Ab3 appears superior to CM2B4 for identifying MCPyV-positive cases.

Inhibiting the immune checkpoint (ICP) PD-1 based on PD-L1 expression status has revolutionized the treatment of various cancers, yet its efficacy in anaplastic thyroid carcinoma (ATC) remains limited. The therapeutic response depends upon multiple factors, particularly the conduciveness of the tumor's immune milieu. This study comprehensively evaluated and classified ATC's immune microenvironment (IME) to elucidate the factors behind suboptimal response to anti-PD therapy. Utilizing multiplex-immunofluorescence and immunohistochemistry, we retrospectively analyzed 26 cases of ATC for expression of ICPs PD-L1, PD-1, CTLA4, TIM3, and Galectin-9 and tumor-infiltrating cytotoxic T lymphocytes (CTL)-the effector cells, the anti-tumor NK cells, the immune-inhibitory myeloid-derived suppressor (MDSC) and regulatory T (Treg) cells, and B lymphocytes. Most ATCs (65%) exhibited PD-L1 positivity, but only 31%, in addition, had abundant CTL (type I IME), a combination associated with a better response to ICP inhibition. Additionally, PD-1 expression levels on CTL were low/absent in most cases-a "target-missing" situation-unfavorable for an adequate therapeutic response. All but one ATC showed nuclear Galectin-9 expression. The documentation of nuclear expression of Galectin-9 akin to benign thyroid is a first, and its role in ATC pathobiology needs further elucidation. In addition to less abundant PD-1 expression on CTL, the presence of MDSC, Treg, and exhausted cytotoxic T lymphocytes in the immune milieu of ATC can contribute to anti-PD resistance. TIM3, the most frequently expressed ICP on CTL, followed by CTLA4, provides alternate therapeutic targets in ATC. The co-expression of multiple immune checkpoints is of great interest for ATC since these data also open the avenue for combination therapies.

Oncocytic thyroid tumors are characterized by an elevated mitochondrial density within the cells, distinguishing them from other thyroid tumors, exhibit distinct clinical behaviors, including increased invasiveness and iodine therapy resistance. However, the proteomic alterations in oncocytic thyroid tumors remain inadequately characterized. In this study, we analyzed 156 Asian patients with oncocytic thyroid adenomas (OA) and carcinomas (OCA) to explore their clinical, genetic, and proteomic features. Genetic testing of 73 samples revealed frequent mutations in TERT, NRAS, EIF1AX, EZH1, and HRAS, with TERT promoter mutations being exclusive to OCAs. Proteomic analysis identified 66 mitochondrial-specific proteins significantly highly expressed in oncocytic tumors than in non-oncocytic tumors. This led to the development of a thyroid oncocytic score (TOS) to quantify oncocytic characteristics. Among these proteins, isocitrate dehydrogenase 2 (IDH2) was substantially overexpressed in oncocytic tumors and further confirmed by immunohistochemistry in oncocytic tumor slides (n = 41) and non-oncocytic tumor slides (n = 40). Moreover, IDH2 is significantly overexpressed in OCA compared to OA highlighting its potential as a biomarker for differential diagnosis of oncocytic tumors and malignancy. These findings improve the understanding of oncocytic thyroid tumors molecular pathology and suggest IDH2 as a valuable marker for clinical management.