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Medulloblastoma is the most common malignant central nervous system tumor in children. The current treatment approach primarily consists of surgery combined with adjuvant radiotherapy and chemotherapy. Postoperative precision treatment plans based on risk stratification effectively prevent overtreatment in low-risk patients while addressing the therapeutic needs of high-risk groups. Traditional clinical risk stratification primarily considers factors such as age, clinical stage, and extent of surgical resection. In recent years, advances in understanding the key molecular markers of medulloblastoma have led to the integration of molecular subtypes and molecular and genetic characteristics into the risk stratification framework. It has resulted in the development of a revised molecular risk stratification system, which makes it possible to distinguish children in different risk groups more efficiently and guides subsequent precision treatment. This paper intends to summarize the pathological characteristics of medulloblastoma, risk stratification based on clinical features and the revised molecular risk stratification which integrates clinical and molecular genetic characteristics, so as to provide a guideline for the formulation of subsequent comprehensive diagnosis and treatment plans.

Abstract The Brazilian Society of Pathology Guidelines Project aims to provide recommendations for clinicians and pathologists based on the best available scientific evidence. It reviews the currently available and emerging histopathological and molecular aspects of bladder cancer that are necessary for the best patient’s management. This paper is a result of a combined effort of the Brazilian Society of Pathology, the Brazilian Society of Urology, and the Brazilian Society of Clinical Oncology to call attention to the essential pre-analytical issues, the required clinical information and specimen handling to allow proper diagnosis, grading, staging and characterization of the molecular aspects of bladder epithelial neoplasms.

Purpose: Dedicated gene signatures in small (SD-iCCA) and large (LD-iCCA) duct type intrahepatic cholangiocarcinoma remain unknown. We performed immune profiling in SD- and LD-iCCA to identify novel biomarker candidates for personalized medicine. Methods: Retrospectively, 19 iCCA patients with either SD-iCCA (n = 10, median age, 63.1 years (45–86); men, 4) or LD-iCCA (n = 9, median age, 69.7 years (62–85); men, 5)) were included. All patients were diagnosed and histologically confirmed between 04/2009 and 01/2021. Tumor tissue samples were processed for differential expression profiling using NanoString nCounter® PanCancer Immune Profiling Panel. Results: With the exception of complement signatures, immune-related pathways were broadly downregulated in SD-iCCA vs. LD-iCCA. A total of 20 immune-related genes were strongly downregulated in SD-iCCA with DMBT1 (log2fc = -5.39, p = 0.01) and CEACAM6 (log2fc = -6.38, p = 0.01) showing the strongest downregulation. Among 7 strongly (log2fc > 2, p ≤ 0.02) upregulated genes, CRP (log2fc = 5.06, p = 0.02) ranked first, and four others were associated with complement (C5, C4BPA, C8A, C8B). Total tumor-infiltrating lymphocytes (TIL) signature was decreased in SD-iCCA with elevated ratios of exhausted-CD8/TILs, NK/TILs, and cytotoxic cells/TILs while having decreased ratios of B-cells/TILs, mast cells/TILs and dendritic cells/TILs. The immune profiling signatures in SD-iCCA revealed downregulation in chemokine signaling pathways inclulding JAK2/3 and ERK1/2 as well as nearly all cytokine-cytokine receptor interaction pathways with the exception of the CXCL1/CXCR1-axis. Conclusion: Immune patterns differed in SD-iCCA versus LD-iCCA. We identified potential biomarker candidate genes, including CRP, CEACAM6, DMBT1, and various complement factors that could be explored for augmented diagnostics and treatment decision-making. [ABSTRACT FROM AUTHOR]

Objective: To determine the feasibility of universal genetic testing of women with newly diagnosed breast cancer, to estimate the incidence of pathogenic gene variants and their impact on patient management, and to evaluate patient and clinician acceptance of universal testing. Design, setting, participants: Prospective study of women with invasive or high grade in situ breast cancer and unknown germline status discussed at the Parkville Breast Service (Melbourne) multidisciplinary team meeting. Women were recruited to the pilot (12 June 2020 – 22 March 2021) and expansion phases (17 October 2021 – 8 November 2022) of the Mutational Assessment of newly diagnosed breast cancer using Germline and tumour genomICs (MAGIC) study. Main outcome measures: Germline testing by DNA sequencing, filtered for nineteen hereditary breast and ovarian cancer genes that could be classified as actionable; only pathogenic variants were reported. Surveys before and after genetic testing assessed pilot phase participants' perceptions of genetic testing, and psychological distress and cancer‐specific worry. A separate survey assessed clinicians' views on universal testing. Results: Pathogenic germline variants were identified in 31 of 474 expanded study phase participants (6.5%), including 28 of 429 women with invasive breast cancer (6.5%). Eighteen of the 31 did not meet current genetic testing eligibility guidelines (probability of a germline pathogenic variant ≥ 10%, based on CanRisk, or Manchester score ≥ 15). Clinical management was changed for 24 of 31 women after identification of a pathogenic variant. Including 68 further women who underwent genetic testing outside the study, 44 of 542 women carried pathogenic variants (8.1%). Acceptance of universal testing was high among both patients (90 of 103, 87%) and clinicians; no decision regret or adverse impact on psychological distress or cancer‐specific worry were reported. Conclusion: Universal genetic testing following the diagnosis of breast cancer detects clinically significant germline pathogenic variants that might otherwise be missed because of testing guidelines. Routine testing and reporting of pathogenic variants is feasible and acceptable for both patients and clinicians. [ABSTRACT FROM AUTHOR]

Patient 2: Occult hepatitis B infection without hepatitis B core antibodies A 50-year-old, HBV unvaccinated female blood donor exhibited reactive multiplex NAT, reactive discriminatory HBV NAT and non-reactive HBsAg results. Keywords: Hepatitis B; Hepatitis, viral; Diagnostic tests and procedures; Serology; Pathology, molecular; Blood banks EN Hepatitis B Hepatitis, viral Diagnostic tests and procedures Serology Pathology, molecular Blood banks 53 55 3 07/18/23 20230717 NES 230717 Clinical records Patient 1: Occult hepatitis B virus infection with hepatitis B core antibodies A 66-year-old, hepatitis B virus (HBV) unvaccinated male blood donor exhibited repeatedly reactive multiplex nucleic acid test (NAT) results for human immunodeficiency virus type 1, hepatitis C virus and HBV, and non-reactive discriminatory HBV NAT and hepatitis B surface antigen (HBsAg) results. Patient 3: Acute hepatitis B virus infection A 46-year-old, HBV unvaccinated male blood donor exhibited reactive multiplex NAT, reactive discriminatory HBV NAT and non-reactive HBsAg results. [Extracted from the article]

Copyright of Der Pathologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aims: This study was undertaken to compare and expand the clinicopathological characteristics of SMARCA4-deficient thoracic undifferentiated tumour (SMARCA4-dUT) and switch/sucrose non-fermentable-deficient non-small cell lung carcinomas (SWI/SNF-dNSCLC) and to address cases with intermediate features., Methods: The pathology department archive was searched for all primary mediastinal, pleural and lung-based malignancies that showed aberrant expression of two SWI/SNF proteins the Brahma (BRM) aka SMARCA2 and/or (Brahma-related gene 1 (BRG1) aka SMARCA4 . Patient demographics, treatment and clinical outcomes were collected from records and telephonic interviews. Differences in histopathological features and immunohistochemical stains were analysed. Cases with characteristics intermediate between both tumour entities were sequenced to advance our understanding of their biology and to assign them a more accurate classification., Results: We identified 50 tumours with SMARCA4 and/or SMARCA2 deficiencies, including 23 (46%) SMARCA4-dUT, 18 (36%) SMARCA4-dNSCLC and 2 (4%) SMARCA2-dNSCLC. Dyscohesive or undifferentiated cellular morphology versus frank gland formation along with keratin, claudin-4 and expression of >1 stem cell marker helped classify the SWI/SNF deficient tumours as SMARCA4-dUT or SWI/SNF-dNSCLC (p<0.05). Seven (14%) cases with BRG1 deficiency displayed 'intermediate' features of both SMARCA4-dNSCLC and SMARCA4-dUT and had the shortest overall survival. The smoking-related gene signature was observed on sequencing in all four cases examined., Conclusion: Tumours with intermediate features between SMARCA4-dUT and SWI/SNF-dNSCLC exist and portend an equally poor prognoses. Immunostains, including keratin, claudin-4, TTF1, HepPar1, stem cell markers, along with BRG1 and BRM testing, are essential adjuncts to morphology, while molecular studies can offer supplementary evidence in challenging cases., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

There is an ongoing explosion of new information regarding the underlying molecular alterations driving a variety of salivary gland neoplasms. The volume of this emerging data makes it difficult to keep up with and may cause pathologists to believe that salivary gland neoplasms cannot be diagnosed without genetic analysis. This review focuses on the practical diagnostic applications of molecular tools in surgical pathology specimens., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Interpretation of variants of uncertain significance (VUSs) remains a challenge in the care of patients with inherited cardiovascular diseases (CVDs); 56% of variants within CVD risk genes are VUS, and machine learning algorithms trained upon large data resources can stratify VUS into higher versus lower probability of contributing to a CVD phenotype., Methods: We used ClinVar pathogenic/likely pathogenic and benign/likely benign variants from 47 CVD genes to build a predictive model of variant pathogenicity utilizing measures of evolutionary constraint, deleteriousness, splicogenicity, local pathogenicity, cardiac-specific expression, and population allele frequency. Performance was validated using variants for which the ClinVar pathogenicity assignment changed. Functional validation was assessed using prior studies in >900 identified VUS. The model utility was demonstrated using the Catheterization Genetics cohort., Results: We identified a top-ranked model that accurately prioritized variants for which ClinVar clinical significance had changed (n=663; precision-recall area under the curve, 0.97) and performed well compared with conventional in silico methods. This model (CVD pathogenicity predictor) also had high accuracy in prioritizing VUS with functional effects in vivo (precision-recall area under the curve, 0.58). In Catheterization Genetics, there was a greater burden of higher CVD pathogenicity predictor scored VUS in individuals with dilated cardiomyopathy compared with controls ( P =8.2×10 - 15 ). Of individuals in Catheterization Genetics who harbored highly ranked CVD pathogenicity predictor VUS meeting clinical pathogenicity criteria, 27.6% had clinical evidence of disease. Variant prioritization using this model increased genetic diagnosis in Catheterization Genetics participants with a known clinical diagnosis of hypertrophic cardiomyopathy (7.8%-27.2%)., Conclusions: We present a cardiac-specific model for prioritizing variants underlying CVD syndromes with high performance in discriminating the pathogenicity of VUS in CVD genes. Variant review and phenotyping of individuals carrying VUS of pathogenic interest support the clinical utility of this model. This model could also have utility in filtering variants as part of large-scale genomic sequencing studies.

Aims: Due to the lack of large clinical cohorts in the Chinese populations with colorectal cancer (CRC) and gastric cancer (GC), there is no consensus among the preferred panel for microsatellite instability (MSI)-PCR testing. This study aims to evaluate a more appropriate panel., Methods: We tested the MSI status of 2572 patients with CRC and GC using the NCI panel and 2 mononucleotide panels (5 and 6 mononucleotide panels). Immunohistochemistry (IHC) was employed to perform mismatch repair protein testing in 1976 samples., Results: We collected 2572 patients with CRC and GC. The National Cancer Institute (NCI) panel failed to detect 13 cases. Of the 2559 cases that received results from all three panels, 2544 showed consistent results. In the remaining 15 cases, 9 showed discrepancies between MSI-H and MSI-L, and 6 showed discrepancies between MSI-L and microsatellite stability (MSS). The misdiagnosis rate of MSI-L was significantly lower in two mononucleotide panels than in the NCI panel (12.5% vs 87.5%, p=0.010) in CRC. In patients with GC, only the NCI panel detected three MSI-L cases, while the results of the two mononucleotide panels were one MSI-H and two MSS. Based on their IHC results, the MSI-L misdiagnosis rate of the NCI panel was 33.3%. Furthermore, compared with two mononucleotide panels, the NCI panel had a much lower rate of all loci instability in CRC (90.8% and 90.3% vs 25.2%) and GC (89.5% and 89.5% vs 12.0%)., Conclusion: In Chinese patients with CRC and GC, the five and six mononucleotide panels have advantages for detecting MSI over the NCI panel., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Few cytologically indeterminate thyroid fine-needle aspirations (FNAs) harbor BRAF V600E. Here, we assess interobserver agreement for The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) category III (atypia of undetermined significance [AUS]) FNAs harboring BRAF V600E and contrast their features with those harboring non-BRAF V600E alterations, with attention to cytopathology experience., Methods: Seven reviewers evaluated 5 AUS thyroid FNAs harboring BRAF V600E. To blind reviewers, cases were intermixed with 19 FNAs falling within other TBSRTC categories and in which genetic alterations other than BRAF V600E had been identified (24 FNAs total). Interobserver agreement against both "index" and most popular ("mode") diagnoses was calculated. Four additional BRAF V600E cases were independently reviewed., Results: Reviewers included 3 trainees and 3 American Board of Pathology (board)-certified cytopathologists. Board-certified cytopathologists, whose experience ranged from 2 to more than 15 subspecialty practice years, had known AUS rates. BRAF V600E was identified in 5 of 260 (2%) AUS FNAs. Interobserver agreement was higher among cytopathologists with more experience. Mode diagnosis differed from index diagnosis in 6 of 11 cases harboring RAS-like alterations; mode diagnosis was AUS in 4 of 5 BRAF V600E FNAs., Conclusions: Atypia of undetermined significance of thyroid FNAs harboring BRAF V600E is uncommon yet relatively reproducible, particularly among pathologists with experience. It is advisable to sequence BRAF across V600 in such cases., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Introduction: This study describes our experience implementing a connected prescription software (NetSIG, Terascop) for molecular pathology exams., Material and Methods: NetSIG was set up for liquid biopsies and tissue testing. After registration and activation of regional pathology laboratories, NetSIG was implemented for external then internal prescriptions., Results: NetSIG allows users to follow up on all prescriptions on the website, to interact through messages and to consult reports after validation. External set up was quick (3-4 months) and comprehensive (>70%). Prescriptions were made by physicians or more often by secretaries or referring pathologists. Internal prescriptions were made by pathologists then registered in NetSIG by our secretaries. This deployment strategy has resulted in very good completeness of prescriptions (>90%)., Discussion and Conclusion: Connected prescriptions made this complex circuit more fluid and facilitated the redistribution of different administrative and technical tasks. The number of phone calls decreased sharply. Half of the prescriptions were made by pathologists and half by oncologists (physicians or secretaries). The mean dearchiving duration for blocks was one day. Mean forwarding of blocks was 2.5 days. Mean turnaround time was 8 days for targeted techniques and 13 days for Next Generation Sequencing. Physicians appreciated the interactivity of the software and the fact that they could consult it on a smartphone., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Whole genome sequencing (WGS) of a tumour may sometimes reveal additional potential targets for medical treatment. Practice variation in the use of WGS is therefore a source of unequal access to targeted therapies and, as a consequence, of disparities in health outcomes. Moreover, this may even be more significant if patients seek access to WGS by paying a relatively limited amount of money out of pocket, and sometimes effectively buy themselves a ticket to (very) expensive publicly funded treatments. Should resulting unequal access to WGS be considered unfair? Drawing from current practice in the Dutch healthcare system, known as egalitarian, we argue that differences in employment of WGS between hospitals are the consequence of the fact that medical innovation and its subsequent uptake inevitably takes time. Consequently, temporal inequalities in access can be deemed acceptable, or at least tolerated, because and insofar as, ultimately, all patients benefit. However, we argue against allowing a practice of out-of-pocket payments for WGS in publicly funded healthcare systems, for four reasons: because allowing private spending favours patients with higher socio-economic status significantly more than practice variation between hospitals does, may lead to displacement of publicly funded health care, does not help to ultimately benefit all, and may undermine the solidaristic ethos essential for egalitarian healthcare systems., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests. Eline Bunnik is a member of the Data Access Board of the Hartwig Medical Foundation, a non-profit national DNA sequencing centre in the Netherlands for cancer diagnosis and research. As a member of the Data Access Board, Eline reviews requests for access to the research database maintained by the Hartwig Medical Foundation, from research groups around the world., (Copyright © 2024. Published by Elsevier Ltd.)

Context.--This article presents a review of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP), including its separation from follicular variant of papillary carcinoma of the thyroid, its evolution, and current definition and pathologic characteristics. Objectives.--To emphasize the understanding of the concept of NIFTP as a neoplasm based on molecular analyses, its critical histopathologic features, the microscopic findings that exclude the diagnosis, and the importance of complete sectioning of the tumor to exclude neoplasms that should be diagnosed as carcinomas. Important distinctions are discussed including difficulties with literature that shows NIFTP with metastases, inadequacy of sectioning of the tumor, and lack of descriptive histology of the surrounding thyroid and possible other lesions. Data Sources.--Review of articles in the English literature on NIFTP, as well as comparative papers showing differences and distinctions between this entity and papillary carcinomas. Conclusions.--This article concludes that with the current state of knowledge on NIFTP with studies from all over the world, this entity is a low-risk neoplasm that, when diagnosed using appropriate criteria, should not be associated with metastatic or recurrent disease, at least on intermediate length of follow-up. This review includes discussion of multifocal NIFTP, as well as the recently defined micro-NIFTP (1 cm or less), and describes features of the tumor that remain to be studied and correlated with outcome: oncocytic variants of NIFTP, percentage of allowable solid areas of growth in the lesions, and definitions of true neoplastic papillae and hyperplastic ones and how these should influence the diagnosis of NIFTP. (Arch Pathol Lab Med. 2021;145:659-663; doi: 10.5858/arpa.2019-0689-RA, The entity known as thyroid follicular variant of papillary carcinoma has been a controversial one for many years. The controversy revolved around 2 features of the lesion: (1) the concept [...]

Abstract Classification of renal cell carcinomas has become more challenging. The 2016 WHO classification included 14 different subtypes and 4 emerging/provisional entities, and recent literature indicates new entities to be incorporated. Nomenclature is based on cytoplasmic appearance, architecture, combination of morphologies, anatomic location, underlying disease, familial syndromes, and specific genetic alterations. Immunohistochemistry is useful in selected cases while it can be insufficient in entities that require molecular confirmation of a specific gene alteration. The aim of these recommendations is to provide a reasonable and optimized approach for the use of ancillary tests in subtyping renal tumors, particularly in resource-limited settings.

Copyright of Der Pathologe is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Since the publication of the 2016 WHO of Tumors of the Central Nervous System (hereinafter referred to as 2016 WHO), many pathologists face challenges and confusion in "integrated diagnosis" practices of 2016 WHO due to financial or technical problems. In this review, the authors combines their practice experiences and their understanding of "cIMPACT ⁃ NOW update 1-4", and they discuss the hot issues of "integrated diagnosis", including: how to diagnose astrocytoma and oligodendroglioma, how to diagnose glioma with H3 gene mutation, How to diagnose IDH wild⁃type/H3 wild⁃type glioma and how to diagnose pediatric glioma. It is hopeful for helping Chinese neuropathologists to have a better understanding of glioma diagnostic terminology. DOI：10.3969/j.issn.1672⁃6731.2019.12.003

Aims: Fibrocartilaginous dysplasia (FCD) is a subvariant of fibrous dysplasia (FD). This study aims to retrospectively elucidate the clinicopathological and separate genetic features of the cartilaginous and fibro-osseous components of FCD., Methods: In total, 24 patients (14 men and 10 women) with FCD were included in our cohort. The diagnosis was confirmed morphologically and immunohistochemically, and genetic features were determined via Sanger sequencing., Results: Five patients were polyostotic, and 19 were monostotic, predominantly concerning the femur. Radiography revealed a well-demarcated ground glass appearance with ring-like or scattered calcification. Histologically, the lesions were characterised by proliferative fibroblasts, immature woven bone and highly differentiated hyaline cartilage. The fibro-osseous components exhibited positive immunoreaction with SATB2 and a low Ki-67 proliferation index. The fibro-osseous and cartilaginous components shared mutations at codon 201 in exon 8 of the guanine nucleotide-binding protein/a-subunit ( GNAS) gene, specifically CGT>CAT (p.R201H) in four patients and the wild-type isocitrate dehydrogenase ( IDH)1/IDH2 gene. Telomerase reverse transcriptase ( TERT) promoter mutations (C288T and C229G) occurred in both fibro-osseous and cartilaginous components in two patients., Conclusions: FCD encompasses areas of conventional FD with additional cartilage. Importantly, the presence or absence of mutations in the GNAS gene and/or the TERT promoter is common between the fibro-osseous and cartilaginous components of the disease. These results further confirmed FCD as a variant of FD., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Aims: Advanced gallbladder carcinoma (AGBC) carries a poor prognosis with dismal survival. There are no data regarding HER2/ERBB2 expression in AGBC. This study evaluated the overexpression of HER2/ERBB2 in cytological aspirates from AGBCs to identify potential patients for whom anti-HER2 targeted therapies can benefit., Methods: This prospective, case-control study was performed on 50 primary AGBC cases. A detailed cytomorphological assessment, followed by immunocytochemistry (ICC) for HER2/ERBB2, was performed on AGBC cell blocks. A similar number of age-matched and gender-matched resected chronic cholecystitis specimens were included as controls. Fluorescence in situ hybridisation (FISH) was performed in equivocal cases., Results: A total of 10 (20%) cases showed positive (3+), 19 (38%) equivocal (2+) expression and 21 (42%) were negative on HER2/ERBB2 ICC. None of the equivocal cases demonstrated HER2 amplification by FISH. Among the controls, none showed positive (3+) immunoexpression, 23 (46%) demonstrated equivocal expression and 27 (54%) were negative. On statistical analysis, HER2/ERBB2 overexpression was significantly associated with AGBC compared with the controls. Of all the clinical, radiological and cytomorphological parameters, the predominant papillary or acinar arrangements of the tumour cells were significantly associated with HER2/ERBB2 overexpression., Conclusions: This is the first study to evaluate the expression of HER2/ERBB2 on cytological aspirates in AGBC using ICC and FISH. HER2/ERBB2 overexpression(20%) was significantly associated with AGBC. Furthermore, predominant papillary or acinar arrangements of tumour cells in the cytological smears were significantly associated with HER2/ERBB2 overexpression. They can serve as potential predictors of HER2/ERBB2 overexpression to select AGBC patients for anti-HER2 targeted therapies., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Aims: Next generation sequencing (NGS) on tumour tissue is integral to the delivery of personalised medicine and targeted therapy. NGS on liquid biopsy, a much less invasive technology, is an emerging clinical tool that has rapidly expanded clinical utility. Gene mutations in cell-free total nucleic acids (cfTNA) circulating in the blood are representative of whole tumour biology and can reveal different mutations from different tumour sites, thus addressing tumour heterogeneity challenges., Methods: The novel Ion Torrent Genexus NGS system with automated sample preparation, onboard library preparation, templating, sequencing, data analysis and Oncomine Reporter software was used. cfTNA extracted from plasma was verified with the targeted pan-cancer (~50 genes) Oncomine Precision Assay (OPA). Assessment criteria included analytical sensitivity, specificity, limits of detection (LOD), accuracy, repeatability, reproducibility and the establishment of performance metrics., Results: An ISO 15189 accredited, minimally invasive cfTNA NGS diagnostic service has been implemented. High sensitivity (>83%) and specificity between plasma and tissue were observed. A sequencing LOD of 1.2% was achieved when the depth of coverage was >22 000×. A reduction (>68%) in turnaround time (TAT) of liquid biopsy results was achieved: 5 days TAT for in-house analysis from sample receipt to a final report issued to oncologists as compared with >15 days from reference laboratories., Conclusion: Tumour-derived somatic variants can now be reliably assessed from plasma to provide minimally invasive tumour profiling. Successful implementation of this accredited service resulted in:Appropriate molecular profiling of patients where tumour tissue is unavailable or inaccessible.Rapid TAT of plasma NGS results., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Aims: Conflicting data were provided regarding the prognostic impact and genomic features of lung adenocarcinoma (LUAD) with lepidic growth pattern (LP+A). Delineation of the genomic and immune characteristics of LP+A could provide deeper insights into its prognostic implications and treatment determination., Methods: We conducted a search of articles in PubMed, EMBASE and the Cochrane Library from inception to January 2024. A domestic cohort consisting of 52 LUAD samples was subjected to whole-exome sequencing as internal validation. Data from The Cancer Genomic Atlas and the Gene Expression Omnibus datasets were obtained to characterise the genomic and immune profiles of LP+A. Pooled HRs and rates were calculated., Results: The pooled results indicated that lepidic growth pattern was either predominant (0.35, 95% CI 0.22 to 0.56, p<0.01) or minor (HR 0.50, 95% CI 0.36 to 0.70, p<0.01) histological subtype was associated with favourable disease-free survival. Pooled gene mutation rates suggested higher EGFR mutation (0.55, 95% CI 0.46 to 0.64, p<0.01) and lower KRAS mutation (0.14, 95% CI 0.02 to 0.25, p=0.02) in lepidic-predominant LUAD. Lepidic-predominant LUAD had lower tumour mutation burden and pooled positive rate of PD-L1 expression compared with other subtypes. LP+A was characterised by abundance in resting CD4+memory T cells, monocytes and γδ T cells, as well as scarcity of cancer-associated fibroblasts., Conclusions: LP+A was a unique histological subtype with a higher EGFR mutation rate, lower tumour mutation burden and immune checkpoint expression levels. Our findings suggested potential benefits from targeted therapy over immunotherapy in LP+A., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Aims: This study aimed to re-evaluate the incidence of hydatidiform mole (HM) and determine gestational trophoblastic disease (GTD) registration rates in Ireland following the establishment of the National GTD Registry in 2017., Methods: We performed a 3-year retrospective audit of HM cases (January 2017 to December 2019) reported in our centre. In 2019, we surveyed Irish pathology laboratories to determine the number of HMs diagnosed nationally and compared this data to that recorded in the National GTD Registry. Additionally, we compared both local and national HM incidence rates to those reported internationally., Results: In the 3-year local audit, we identified 87 HMs among 1856 products of conception (POCs) providing a local HM incidence rate of 3.92 per 1000 births. The 1-year pathology survey recorded 170 HMs in 6008 POCs, yielding a national incidence rate of 2.86 per 1000 births. Importantly, the local HM incidence rate exceeded the national incidence rate by 37% and the local partial HM incidence (1 in 296 births) was 64% higher than the nationally incidence rate (1 in 484 births). Notably, 42% of the HM and atypical POCs diagnosed nationally were not reported to the National GTD Registry., Conclusions: Our study reveals increased HM incidence rates both locally and nationally compared with previous Irish studies. The higher local PHM incidence may reflect more limited access to ploidy analysis in other pathology laboratories nationally. Significantly, almost half of the women with diagnosed or suspected HM were not registered with the National GTD Centre., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Aims: Diagnosis of hydatidiform mole or molar pregnancy based on morphology alone can be challenging, particularly in early gestation, necessitating the use of ancillary techniques for accurate diagnosis. We sought to adapt the VENTANA HER2 dual-colour dual-hapten in-situ hybridisation (D-DISH) assay by using the internal chromosome 17 enumeration probe to determine ploidy status., Methods: We selected 25 products of conception, consisting of molar and non-molar cases, to validate the HER2 D-DISH assay. These cases had prior morphological assessment by a perinatal pathologist and ploidy analysis using molecular cytogenetics. Three independent observers, blinded to the original histopathological and genetic diagnosis, scored 10 representative areas on each slide. Interobserver variability was assessed by comparing the total scores of each observer using analysis of variance (ANOVA) and the kappa statistic., Results: Our ploidy scoring system accurately determined the correct number of diploid and triploid conceptuses, demonstrating complete concordance with pre-existing ploidy status and the initial diagnosis. Interobserver agreement between three independent scorers was robust: ANOVA (p=0.36) and kappa statistic (0.812, p<0.001). We achieved clear separation of average nuclear signals for diploid and triploid conceptuses, which was statistically significant (p<0.05). Employing our innovative scoring system, known as the 'rule of 5', we established ploidy decision thresholds for all 25 cases., Conclusions: Our modified HER2 D-DISH ploidy assay simplifies the process of ploidy determination and improves the accuracy of morphological diagnosis of molar pregnancy. The HER2 D-DISH assay was selected for ploidy analysis due to the widespread availability of in-situ hybridisation in pathology laboratories., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)

Objectives: The International Consensus Classification (ICC) and 5th Edition of the World Health Organization Classification (WHO-5) made substantive updates to the classification of myeloid neoplasms. This study compares the systems in a series of myeloid neoplasms with increased blasts, analyzing implications for diagnostic workflow and reporting., Methods: Bone marrow biopsies categorized as myelodysplastic syndrome with excess blasts (MDS-EB) or acute myeloid leukemia (AML) by WHO-R4 were identified. Results of morphology review, karyotype, fluorescence in situ hybridization, and next-generation sequencing were compiled. Cases were retrospectively re-classified by WHO-5 and ICC., Results: 46 cases were reviewed. 28 cases (61 %) had ≥20 % blasts, with the remaining cases having 5-19.5 % blasts. The most common differences in classification were 1) the designation of MDS versus MDS/AML (10/46, 22 %) for cases with 10-19 % blasts and 2) the ICC's designation of TP53 variants as a separate classifier for AML (8/46, 17 %). Bi-allelic/multi-hit TP53 alterations were identified in 15 cases (33 %). Variants of potential germline significance were identified in 29 (63 %) cases., Conclusions: While terminology differences between WHO-5 and ICC exist, both systems invoke similar opportunities for improved reporting: standardized classification of pathogenic variants (notably TP53), streamlined systems to evaluate for potential germline variants, and integrated reporting of morphologic and genetic data., Competing Interests: Declaration of competing interest The authors have no financial relationships or conflicts of interest to disclose., (Copyright © 2024. Published by Elsevier Inc.)

Aims: To investigate the performance of a combined biomarker approach using the methylation status of the short stature homeobox 2 ( SHOX2 ) and prostaglandin E2 receptor EP4 ( PTGER4 ) genes, along with the serum levels of CYFRA21-1, for differential diganosis of malignant pleural mesothelioma (MPM) from benign reactive mesothelial hyperplasia (RMH)., Methods: We analysed 48 MPM tissue or pleural effusion cell block specimens and 42 cases with RMH. Real-time quantitative methylation-specific PCR was used to examine the methylation status of SHOX2 , PTGER4 , ras association domain family 1 isoform A, septin 9 gene and homeobox gene A9 genes. Additionally, we employed electrochemiluminescence immunoassay to measure nine serum tumour markers commonly used in pan-cancer screening tests., Results: The receiver operating curve indicated that SHOX2 , PTGER4 gene methylation and serum biomarker CYFRA21-1 exhibited good diagnostic performance in identifying MPM, with area under curves (AUCs) of 0.761, 0.904 and 0.847, respectively. The combination of SHOX2 , PTGER4 methylation and CYFRA21-1 yielded an AUC value of 0.972. The diagnostic sensitivity and specificity of this panel in differentiating MPM from RMH were 91.3% (42/46) and 97.6% (41/42), respectively. Both tissue and cell block specimens can be used in the diagnostic process. Furthermore, elevated CYFRA21-1 levels were associated with poor prognosis (p<0.05). Hypermethylation level of PTGER4 may indicate an unfavourable prognosis of MPM, but the difference was not statistically significant., Conclusions: The combined detection of SHOX2 and PTGER4 methylation alongside serum CYFRA21-1 level significantly enhances the diagnosis of MPM. Additionally, CYFRA21-1 can serve as a prognostic indicator for MPM., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Aims: Specific identification of a hydatidiform mole (HM) and subclassification of a complete hydatidiform mole (CHM) or partial hydatidiform mole (PHM) are critical. This study aimed to reappraise the diagnostic performance of ultrasonography and histology with a refined diagnosis., Methods: This was a retrospective, multicentre cohort study of 821 patients with histologically suspected HM specimens. Refined diagnostic algorithms with p57 immunohistochemistry and short tandem repeat (STR) genotyping were performed and used as the true standard for assessing the diagnostic performance of the original ultrasonography and morphology methods. The diagnostic performance was calculated using accuracy, agreement rate, sensitivity and the positive predictive value (PPV) compared with refined diagnostic results., Results: Of the 821 histologically suspected HM cases included, 788 (95.98%) were successfully reclassified into 448 CHMs, 213 PHMs and 127 non-molar (NM) abortuses. Ultrasonography showed an overall accuracy of 44.38%, with a sensitivity of 44.33% for CHM and 37.5% for PHM. The overall classification accuracy of the original morphological diagnosis was 65.97%. After exclusion of the initially untyped HMs, the overall agreement rate was 59.11% (κ=0.364, p<0.0001) between the original and refined diagnoses, with a sensitivity of 40.09% and PPV of 96.05% for diagnosing CHMs and a sensitivity of 84.98% and a PPV of 45.59% for diagnosing PHMs. The interinstitutional variability of morphology in diagnosing HMs was significant among the 15 centres (range, 8.33%-100.00%, p<0.0001)., Conclusion: The current diagnosis of HM based solely on ultrasound or morphology remains problematic, and ancillary techniques, particularly p57 immunohistochemistry and DNA genotyping, should be integrated into routine practice as much as possible., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)