Background
Sentinel Lymph node ultrastaging (SLN-US) allows enhanced detection of low-volume nodal metastases not identified on routine H&E. SLN-US was introduced to St James’s Hospital in 2020.

Aim
To determine the rate of H&E-occult nodal metastases detected by SLN-US over a five-year period and to describe the histopathological features of cases positive on ultrastaging.

Methods
A retrospective audit was performed of all endometrial cancer cases that underwent SLN-US from 2020-2024. Cases with primary lymphadenectomy or bilateral positive SLNs were excluded. SLNs were processed in accordance with BAGP ultrastaging guidelines. Occult metastases were categorised as micrometastases or isolated tumour cells (ITCs). Recorded parameters included depth of myometrial invasion (MI), tumour grade and lymphovascular space invasion (LVSI). Associations were assessed using Chi-square/Fisher’s exact test via SPSS.

Results
172 cases met inclusion criteria. Occult SLN metastases were identified in 15/172 (8.7%): 2 micrometastases, 11 ITCs, with 2 cases demonstrating both. Among positive cases, 10 (66.7%) displayed LVSI, 11 (73%) displayed >50% deep myometrial invasion and 4 (26%) were high grade. In addition, ultrastaging was used to confirm 6 further cases where lymph node invasion was suspected, but not confirmed on initial H&E. Occult metastases were strongly associated with LVSI (10/15, 66.7% vs 26/157, 16.6%; p < 0.001) and MI ≥50% (11/15, 73% vs 38/157, 24.2%; p < 0.001), but not tumor grade (high grade 26.7% vs 12.1%; p = 0.113).

Conclusion
SLN ultrastaging detects occult metastases in a significant proportion (8.7%) of endometrial cancers. LVSI or deep MI was present in 14/15 (93%) node-positive cases. Given the significant resource implications of SLN-US, this analysis emphasises the importance of determining the clinical relevance of low volume metastases and raises the possibility of safely omitting SLN-US in cases without LVSI or deep MI.

Background

Endometrial cancer is the sixth most common female malignancy. Genetic instability and mutations in oncogenes, tumour-suppressor genes and DNA repair pathways drive carcinogenesis. So-called neopeptides, derived from mutated proteins, are processed and presented on human leukocyte antigen (HLA) molecules by cancer cells, permitting immune surveillance by CD8+ T cells, triggering clonal expansion and targeted cytotoxic killing. While the frameshift mutations of microsatellite unstable (MSI) endometrial cancers produce abundant neopeptides, with consequent intense immune infiltration, microsatellite stable (MSS) tumours (~75% of cases) harbour fewer mutations, show limited immune engagement and respond poorly to immunotherapies.

Purpose

Here, we investigate patterns of tumour cell somatic mutation and TCRβ repertoires in tumour-infiltrating lymphocytes (TILs) in MSS endometrial cancers, ultimately aiming to uncover therapeutic or early detection targets in a disease with substantial unmet need.

Methods

Whole-exome sequencing (WES) was performed on tumour-extracted genomic DNA (gDNA) to identify somatic mutations and patient HLA types. Candidate neopeptides for the patient’s specific HLA type were determined using in silico immunogenicity prediction tools. Bulk-TCRβ sequencing of gDNA from TILs was performed and analysed using MiXCR, followed by cluster analysis based on TCRβ clonotypes sequence similarity.

Results

In MSS endometrial cancers, WES revealed patient HLA types, and mutations in genes involved in DNA repair, cell-signalling and proliferation, including PIK3CA, PTEN and TP53. Further analysis yielded insights into tumour purity and clonal architecture. Bulk-TCR sequencing revealed variably diverse TCR repertoires, with expanded clonotypes and variation in TCR gene-segment usage between patients.

Conclusions

We have identified multiple candidate neoantigens in MSS endometrial cancer and assessed their likelihood of being presented to T cells, as well as identifying expanded TCR clonotypes. Our results will permit functional validation in peptide-HLA binding assays using patient-derived TILs and single T-cell sequencing to define TCR-neopeptide interactions, uncovering actionable targets for immunotherapy or early cancer detection.

Background: Glioblastomas, are the most aggressive primary CNS tumors in adults. Microvascular density (MVD), a measure of angiogenesis, affects the tumor's invasiveness and rate of growth. Increased expression of CD105, which is crucial for regulating angiogenesis with an active proliferative capacity. HIF-1α levels can help identify hypoxia niches in gliomas and guide treatment choices.
Purpose: To study the immunohistochemical expression of HIF 1α and CD105 with cytohistological and clinicoradiological correlation.
Methods: Tertiary care hospital and lab based prospective observational study of one year duration. The clinically & radiologically suspected 45 glioma cases were included for squash smear cytology, histopathology, immunohistochemical expression of HIF 1 Α & CD105. Statistical tools were used mean, standard deviation, chi-square test and kappa test.
Results: Most common diagnosis was adult type diffuse gliomas, Astrocytoma, IDH mutant (31.1%) followed by Glioblastoma, IDH wild type (28.9%), Paediatric type diffuse low grade glioma , IDH mutant(6.7%)and rest (33.3%). Moderate level of agreement between clinical and radiological diagnosis have been observed (=0.571; p<0.001) .The concordance between squash cytology and histopathology was 82.2%, showing moderate agreement. Higher HIF-1α expression correlated significantly with higher CD105 mean vascular density and glioma grade. HIF-1α and CD 105 expression were higher in IDH1 wild-type tumors but differences were not statistically significant. Patients with strong HIF-1α and high CD105 expression had shorter survival, mean duration of overall survival was 7.89±5.21 months. The study emphasizes the importance of the tumor microenvironment, particularly hypoxia and angiogenesis in glioma progression and patient outcomes, suggesting these factors as key targets for more effective, individualized therapies.
Conclusions:Therefore, it was found that, both HIF-1α and CD 105 are promising prognostic biomarkers. Their expression levels correlate with tumor aggressiveness and could potentially aid in therapeutic targeting. Hence, monitoring these markers may help in predicting outcomes,guiding prognosis and treatment strategies in glioma patients.

Background
Several trials such as INSEMA and SOUND demonstrated that a sentinel lymph node biopsy (SLNB) can be safely omitted in selected patients with early-stage, hormone receptor-positive HER2-negative invasive breast cancer with clinically negative axillary lymph nodes. Despite the non-invasive nature of pure ductal carcinoma in situ (DCIS), many women still undergo an SLNB as part of the DCIS treatment.
Purpose
To retrospectively investigate which patients with a biopsy-diagnosis of pure DCIS can safely forego an SLNB. De-escalation of axillary surgery could reduce surgical morbidity.
Methods
A comprehensive histopathological evaluation was performed of archived whole-tissue slides of 262 biopsy-diagnosed DCIS, comprising grade, necrosis, DCIS architecture, myxoid stroma, calcifications, and tumour-infiltrating lymphocytes. Immunohistochemistry was performed for oestrogen (ER) and progesterone receptor (PR), and HER2. Upstaging to invasive carcinoma (≥pT1mi) was the outcome.
Results
None of the histopathological and immunohistochemical features was associated with upstaging, except for absence of calcifications (p=0.017) and solid DCIS architecture (p=0.012), constituting the ‘high risk profile’. Twelve of 59 patients (20%) with ER-positive, HER2-negative DCIS treated with mastectomy showed upstaging, but only two (3%) showed axillary lymph node metastases. After excluding the ‘high risk profiles’, upstaging risk was 6%, without axillary lymph node metastases. Based on these data, we developed a decision flowchart, analogous to the SOUND and INSEMA trials for invasive carcinoma. The flowchart uses ER and HER2 status, solid DCIS architecture and lack of calcifications, and was correlated with the surgery type and upstaging risk. PR status had no added value.
Conclusions
DCIS patients with a low-risk profile (i.e., ER-positive, HER2-negative DCIS without solid architecture and with calcifications) can forego an SLNB, even when treated with mastectomy. The routine implementation of this flowchart requires systematic assessment of the HER2 status of DCIS, and might substantially de-escalate axillary surgery for DCIS patients in the future.

Background
Meningiomas are the most common primary tumour of the central nervous system. While the vast majority are benign (WHO grade 1), a small proportion show atypical or malignant features. Identification of these cases is important as they are more likely to recur; closer clinical follow up +/- radiotherapy may be indicated in such cases.
Meningioma grading as per the 2021 WHO classification of CNS tumours integrates histological features (including mitoses, growth pattern, brain invasion) with molecular findings (TERT promoter variant, CDKN2A biallelic inactivation). However, despite molecular integration there are cases that behave more, or less, aggressively than their WHO grade suggests.

Purpose
Recent publications investigating the genomic, transcriptomic and proteomic landscape of meningiomas have proposed novel grading systems. These include immunohistochemical panels[1] and copy number variation (CNV) based approaches[2,3]. We investigated the clinical applicability of these methods in a real-world setting, assessing their capacity to discriminate high-risk from low-risk cases.

Methods
100 consecutive cases of meningioma, with over 10 years of follow up data, were scored according to 4 grading systems: namely these were conventional CNS WHO 2021 grading; cIMPACT-NOW 2024 grading; integrated grading as per Driver et al., 2022; and immunohistochemical grading as per Nassiri et al., 2021. Time-to-recurrence Kaplan-Meier curves were produced by grade for each method.

Results
Integrated grading as per Driver et al. provided better discrimination between high, intermediate and low-risk cases than standard CNS WHO 2021 grading. cIMPACT-NOW provided robust stratification of low risk cases from intermediate/high risk. Immunohistochemical grading was not feasible due to 63 % of tumours either staining for multiple markers, or for none, precluding confident grade designation.

Conclusions
In the context of readily available CNV analysis by methylation array, Integrated grading and cIMPACT-NOW grading are applicable clinically and provide an improvement in risk stratification than CNS WHO 2021 grading alone.