Search Results (589)

Angiogenesis is a key process in colorectal cancer (CRC) progression, with vascular endothelial growth factor A (VEGFA) being a major pro-angiogenic mediator. miR-195-5p has previously been identified by our group as a tumor-suppressive miRNA downregulated in CRC. Here, we aimed to investigate whether miR-195-5p contributes to CRC-associated angiogenenic processes through VEGFA regulation. Potential miR-195-5p targets were investigated through bioinformatic predictions and miRNA Target RNA immunoprecipitation. VEGFA expression was evaluated in public CRC datasets and paired tumor/adjacent tissues of a cohort of CRC patients by quantitative real-time PCR and immunohistochemistry. miR-195-5p gain- and loss-of-function experiments were performed in CRC cells to assess VEGFA and VEGFR2 expression and extracellular VEGF-A levels by ELISA. Endothelial tube formation assays using HUVECs were conducted to evaluate paracrine angiogenic effects. VEGFA expression was also analyzed in an AOM/DSS-induced murine CRC model treated with a miR-195-5p mimic. VEGFA was predicted as a conserved miR-195-5p target and was enriched in miR-195-5p-associated RISCs. VEGFA was overexpressed in CRC tissues compared to normal or adjacent non-tumor tissues. miR-195-5p restoration reduced VEGFA mRNA and protein expression, extracellular VEGF-A levels, and VEGFR2 protein levels in the HCT116 CRC cell line, whereas miR-195-5p inhibition produced the opposite molecular profile. Conditioned media from miR-195-5p-overexpressing CRC cells significantly impaired endothelial tube formation. Consistently, miR-195-5p in vivo administration reduced colonic Vegfa expression in AOM/DSS-treated mice. Overall, these findings indicate that miR-195-5p negatively modulates VEGFA expression and reduces the ability of CRC cell-derived conditioned media to support endothelial tube formation. This study extends the tumor-suppressive functions previously attributed to miR-195-5p by supporting its involvement in the regulation of angiogenesis-related processes in CRC. Full article

Background/Objectives: Identification of cell-surface receptors on cancer tissues that are absent in the corresponding normal tissue provide an opportunity for target-specific diagnostics and drug delivery. The cholecystokinin-B receptor (CCKBR) was initially overlooked as a high-priority biomarker for pancreatic cancer (PDAC) because comparisons were made between cancer and “normal adjacent tissue” from The Cancer Genome Atlas (TCGA). Since PDAC is highly invasive and significantly alters the tumor microenvironment, we now know the adjacent tissue is not normal in PDAC. Methods: A multi-cohort transcriptomic analysis was conducted to evaluate the true expression landscape of CCKBR in human pancreatic tissue. Bulk RNA-sequencing data were harmonized from the Genotype-Tissue Expression (GTEx) repository (N = 328) with true normal pancreas samples and TCGA Pancreatic Adenocarcinoma cohort (N = 178) primary tumors. Confirmation of CCKBR protein expression was performed using a human tissue array. The significance of a single-nucleotide polymorphism (SNP, rs1800843) that results in CCKBR mis-splicing was characterized. A biodegradable fluorescent polyplex nanoparticle (NP) was developed to selectively target the CCKBR and was tested using p48-Cre/LSL-Kras^G12D (KC) mice. Results: CCKBR transcripts exhibited a profound, binary-like upregulation in malignant tissue compared to normal tissue, achieving statistical significance (p = 10⁻⁶⁰). The germline SNP of the CCKBR (rs1800843) was identified in ~40% of patients with confirmed PDAC. Immunoreactivity for the CCKBR protein was absent in normal human pancreas but increased in precancerous PanIN lesions and cancer. A fluorescent labeled CCKBR-targeted NP revealed uptake in the pancreas of KC mice and localized to the PanIN lesions. Conclusions: These data provide new insights into CCKBR, supporting its potential as a diagnostic biomarker and a therapeutic target in precision pancreatic oncology. Full article

Radiation therapy is a cornerstone in the treatment of abdominal, pelvic, thoracic, head and neck and central nervous system malignancies. However, irradiation inevitably damages adjacent normal tissues, leading to radiation-induced enteritis, lung injury, cardiac injury, salivary gland dysfunction and brain injury, which compromise both quality of life and treatment outcomes. Traditional two-dimensional cell cultures and animal models have significant limitations in mimicking human tissue radiation responses: the former lacks three-dimensional architecture and cell–cell interactions, while the latter exhibits species-specific differences. In recent years, three-dimensional organoid technology has rapidly emerged as a powerful platform in radiation biology and radiation oncology. In particular, organoids derived from patient tissues or induced pluripotent stem cells (hiPSCs) offer key advantages, including self-organization capacity and near-physiological tissue structure and function, which have greatly advanced in-depth research in the radiation field. This review comprehensively summarizes applications of human organoids in radiation injury and regeneration research across the brain, heart, lung, esophagus, salivary gland, intestine, muscle, thyroid, hematopoietic system, and tumors. Animal-derived and organotypic models are included only as comparative or supporting mechanistic evidence and are explicitly identified as such. We focus on advances in modeling radiation injury, elucidating regenerative mechanisms, screening radioprotective and radiosensitizing agents and predicting patient responses to chemoradiation. Current limitations and future directions are discussed collectively at the end. Full article

Background: Oral cancer is the sixth most prevalent cancer globally, posing a significant health concern, especially in India, where it accounts for one-third of all cases. The current work aimed to investigate gene signatures and identify their possible causes in OC using bioinformatics. Methods: The Gene Expression Omnibus (GEO) database was used to acquire data for OC. Differentially expressed genes (DEGs) in the control and case groups were determined using GeneSpring analysis. A protein–protein interaction (PPI) network and functional enrichment were built for DEGs. qPCR of four selected hub genes (STAT1, MMP9, CXCL8 and ISG15) was carried out in 20 OC tissues along with their adjacent normal tissue and 10 extracellular vesicle transcripts derived from serum samples of oral cancer patients and a healthy volunteer. Results: Experimental qPCR results of all four hub genes displayed a similar expression pattern as observed using bioinformatics tools. Conclusions: Together, the essential genes that were shortlisted might further increase our comprehension of the molecular processes underlying the etiology of OC and function as a possible candidate biomarker for OC. Full article

Endometrial carcinoma (EC) is the most common malignancy of the female genital tract, yet reliable prognostic biomarkers remain limited. Matrin-3 (MATR3), a nuclear matrix protein involved in genome stability and RNA processing, has been implicated in various cancers, but its role in EC has not been described. Here, we performed an integrated analysis combining immunohistochemical evaluation of MATR3 protein expression in a retrospective institutional cohort of 112 patients with EC and in silico analysis of MATR3 mRNA expression in 172 TCGA cases. Immunohistochemical analysis revealed nuclear MATR3 expression in both EC and normal endometrial tissues, with significantly lower protein levels in EC compared to control tissues (p < 0.0001). MATR3 mRNA was significantly reduced in EC tumour tissues compared to adjacent normal tissues (p < 0.0001). Low MATR3 protein expression was associated with shorter OS after adjustment for age, histological grade, pT, pN and pM in an LVSI-stratified Cox model (HR = 2.296; 95% CI: 1.284–4.104; p = 0.0050). Low MATR3 mRNA expression was associated with improved overall survival in TCGA (median OS = 110.1 months; HR = 2.174; 95% CI: 1.066–4.43; p = 0.0303). Co-expression analysis identified BCLAF1 and TOP2B as key positive correlates, while TRAPPC5 and FASTK showed the strongest negative correlations. Genes positively correlated with MATR3 mRNA expression were enriched for nuclear transcription and RNA-processing annotations, whereas negatively correlated genes were enriched for mitochondrial processes. These associations do not establish a mechanistic link between MATR3 and pathway activity. Our findings support further investigation of MATR3 as a candidate prognostic marker in EC, with independent validation and functional studies required. Full article

Esophageal adenocarcinoma (EAC) is molecularly heterogeneous, and prognostic models with clear biological context remain limited. We analyzed RNA-sequencing and clinical data from 46 EAC tumors and 13 adjacent normal tissues in The Cancer Genome Atlas. Differential expression, ESTIMATE, weighted gene co-expression network analysis, and LASSO–Cox regression were used to derive a tumor microenvironment-associated score, followed by bootstrap and nested cross-validation, assessment in independent cohorts, immune deconvolution, and single-nucleus RNA-sequencing analysis. We identified 1571 differentially expressed genes and an 879-gene module associated with stromal, immune, and tumor-purity traits. A four-gene score comprising ACSM1, AGT, IGF2BP3, and ESM1 stratified overall survival in the development cohort. The optimism-corrected C-index was 0.769, whereas the median nested cross-validation C-index was 0.589. In GSE13898, the locked score identified Cluster B with a rank AUC of 0.923; however, survival associations were not reproduced in GSE72873 or GSE254942. Immune-cell comparisons showed nominal differences that did not remain significant after BH correction. Single-nucleus analysis localized IGF2BP3 mainly to malignant cells and ESM1 to endothelial cells. The score provides molecular-subtype and cellular context for hypothesis generation, but its prognostic generalizability remains unestablished. Full article

Background: Prognostic gene expression signatures in colorectal cancer are usually reported by standalone discrimination, a standard that random gene sets can meet, and are rarely tested for what they add to routine clinical variables. Methods: TCGA-COAD and TCGA-READ were pooled into a single colorectal cohort (596 patients, 153 progression-free events). PathKAN places learnable univariate spline functions on a sparse gene-to-pathway topology drawn from MSigDB and BioGRID, reducing 20,681,472 dense weights to 127,985 edges, and is fitted under a Cox partial-likelihood objective. Performance was assessed by nested, repeated stratified cross-validation with dependence-corrected inference against clinical, elastic-net Cox and random survival forest models, and the frozen network was applied to four independent cohorts (1012 patients, 306 events) on two array platforms. Results: The out-of-fold score was associated with progression-free interval independently of stage, age, sex and tumour site (adjusted HR 1.25 per SD, 95% CI 1.06–1.47; likelihood-ratio p = 0.008), but raised concordance only from 0.699 to 0.711, a gain whose 95% confidence interval included zero. The frozen model remained independently prognostic in the two larger treatment-naive validation cohorts (p = 0.003 and p = 0.008) but not in the two smaller cohorts, and was not prognostic in oesophageal or lung adenocarcinoma. Individual learned edge functions were often non-monotonic but were not reproducible across refits, whereas gene-level partial-dependence curves were stable and largely monotone, and only some of the top-ranked genes recurred consistently. Of the 50 highest-ranked genes, 42 were differentially expressed between tumour and adjacent normal tissue. Conclusions: A pathway-masked Kolmogorov–Arnold survival model yields an interpretable transcriptomic score associated with colorectal cancer progression independently of clinical stage. It improves model fit over clinical variables, but its gain in discrimination is small and not statistically established; its transportability depends partly on outcome-blind, cohort-level standardisation of the inputs, and its clinical utility remains to be established. Full article

Pancreatic ductal adenocarcinoma (PDAC) progression is driven by complex cellular interactions within the tumor microenvironment (TME), where endothelial cell (EC)-tumor-associated macrophage (TAM) crosstalk significantly influences angiogenesis and immune modulation, although the specific subsets and consequences remain unclear. Here, we integrated four single-cell RNA sequencing datasets (50 PDAC; 21 normal adjacent tissues) to profile EC and macrophage subpopulations, subsequently employing CellChat to decipher intercellular communication networks and identify altered ligand–receptor interactions in PDAC. Correlation and Kaplan–Meier survival analyses (TCGA-PAAD) assessed associations and prognostic value, while functional validation used EdU, CCK-8, and Transwell assays on PDAC cells. We identified a distinct endothelial subset (EC0) and macrophage subset (Mac2) with enhanced interaction signals in PDAC. This EC0–Mac2 crosstalk correlated with significant S100A6 upregulation, which was associated with poor patient prognosis. Exogenous S100A6 treatment markedly enhanced PDAC cell proliferation and migration in vitro. In conclusion, EC-Mac crosstalk may promote PDAC progression via S100A6, and this interaction pattern warrants further investigation as a candidate prognostic biomarker and potential target for disrupting stromal communication. Full article

Background/Objectives: Post-traumatic nasal pyramid reconstruction is challenging in patients with severe deformity and exhausted autologous graft options, particularly after multiple failed surgeries. Custom-made titanium implants may offer precise structural support, but data on their mucosal integration and ultrastructural tissue response in nasal reconstruction are lacking. The aim of this study is to describe what is, to the best of our knowledge, the first reported case of nasal pyramid reconstruction using an IPS (Individual Patient Solutions) custom-made titanium implant and to evaluate peri-implant tissue response with transmission electron microscopy (TEM). Methods: A 50-year-old male military personnel with long-standing saddle-nose deformity, nasal obstruction, and prior failed graft-based reconstructions underwent open rhinoplasty with placement of a patient-specific titanium implant designed with three-dimensional virtual surgical planning on the basis of established nasal anthropometric parameters and manufactured as a custom-made device under Regulation (EU) 2017/745. The implant reconstructed the nasal dorsum from nasion to tip and was stabilized with cortical screws; an additional thin titanium plate was used for tip support. Biopsies of nasal mucosa and adjacent connective tissue obtained 24 months postoperatively were processed for TEM to assess epithelial, stromal, vascular, and implant–tissue interface characteristics. Results: Clinically, nasal airway patency improved immediately after packing removal, with restoration of nasal contour and stable functional and aesthetic outcomes at 24-month follow-up without complications. Ultra-structurally, the respiratory epithelium showed preserved stratification, intact basal and ciliated cells, normal nuclei and mitochondria, and organized extracellular matrix closely opposed to discrete titanium particles, without granulomatous foreign-body reaction, dense inflammatory infiltrate, or fibrotic encapsulation. Focal ciliary damage, cytoplasmic vacuolization, lamina propria thickening, and vascular elastic lamina remodeling were interpreted as adaptive or transient stress-related changes rather than chronic implant toxicity. Conclusions: Custom-made IPS titanium implants can provide stable structural support, satisfactory functional and aesthetic outcomes, and a well-tolerated mucosal interface in complex post-traumatic nasal pyramid reconstruction after failed graft-based surgeries. The ultrastructural findings are being consistent with good local tolerance of the implant at 24 months, showing predominantly preserved epithelial and stromal architecture with only focal, adaptive stress-related changes rather than chronic implant-related toxicity. However, as this is a single case assessed without conventional histology, immunohistochemistry or objective measurement of nasal airflow, these observations cannot establish biocompatibility, efficacy or long-term safety, and require confirmation in larger series with longer follow-up. Full article

Hepatocellular carcinoma (HCC) is characterized by extensive molecular heterogeneity, yet changes in protein abundance alone may not fully capture the regulatory alterations that drive tumor biology. Here, we performed integrated whole-proteome and phosphoproteome profiling of paired HCC and adjacent non-tumorous liver tissues to distinguish protein-abundance remodeling from phosphorylation changes not explained by comparable parent-protein abundance changes. Label-free nano-LC-MS/MS data were processed using quality control, filtering, missing-value imputation, normalization, and paired statistical testing. Whole-proteome analysis retained 3653 proteins and identified 314 significantly altered proteins, including 79 increased and 235 decreased proteins in HCC. Phosphoproteome analysis retained 1682 phosphopeptides and identified 189 significantly altered phosphopeptides, including 81 increased and 108 decreased events. Integrated analysis showed that 132 significant phosphopeptides matched quantified parent proteins; 112 were classified as phospho-only events, and 20 showed concordant phosphopeptide and parent-protein changes. Reactome enrichment of phospho-only parent proteins highlighted immune/inflammatory processes, metabolic remodeling, ER-stress/protein-folding responses, apoptosis, RHO/RHOBTB GTPase-related regulation, and post-translational phosphorylation. Candidate prioritization identified phosphorylation events for future validation. Overall, this paired multi-layer proteomic analysis demonstrates that HCC tissue exhibits both protein-abundance remodeling and phosphorylation-level rewiring, supporting integrated proteome–phosphoproteome profiling as a strategy to resolve regulatory alterations in cancer tissue. Full article

Radiotherapy (RT) is an essential treatment modality for solid tumors and achieves tumor control primarily through radiation-induced cytotoxicity. However, its biological effects extend beyond direct tumor-cell killing. Radiation inevitably affects surrounding normal and tumor-adjacent tissues, inducing inflammatory, stromal, extracellular-matrix, vascular, and cellular remodeling that can persist after treatment. Accumulating experimental evidence indicates that these tissue responses can generate microenvironments permissive to the survival and regrowth of residual tumor cells, local reseeding, and metastatic colonization. This review examines radiation-induced tumor-promoting niches as an unintended consequence of tissue injury and repair. Experimental and clinical evidence supporting their existence is summarized, followed by discussion of the major biological processes underlying their formation, including immune remodeling, fibroblast activation and extracellular-matrix reorganization, vascular injury and hypoxia-driven reparative vasculogenesis, and cellular senescence. Emerging strategies to prevent or attenuate these niches are also discussed, including limiting normal-tissue radiation exposure and selectively targeting persistent inflammatory and stromal responses, post-radiation vasculogenesis, and senescent cells. Although direct causal evidence remains predominantly preclinical and the clinical significance of these responses remains to be established, understanding how irradiated tissues evolve after treatment may reveal opportunities to preserve the therapeutic benefits of RT while minimizing long-term tissue conditions that favor tumor recurrence or metastatic progression. Full article

Endometrial cancer incidence is markedly rising globally, posing an urgent need to elucidate the molecular mechanisms driving disease characterization and progression. Endometrial cancer evolution is driven by canonical Wnt and p53 pathway alterations, yet the mechanisms orchestrating the transition from localized proliferation to stromal invasion, the proliferation–invasion dichotomy, remain poorly understood. While long non-coding RNAs (lncRNAs) are emerging as critical correlates of divergent tumor phenotypes, their coordination with the broader ubiquitin–proteasome system (UPS), specifically E3 ligase and deubiquitinase (DUB) networks, during endometrial cancer progression is largely unexplored. Whole-transcriptome RNA sequencing was performed on formalin-fixed paraffin-embedded (FFPE) tissue from a clinical cohort of 38 patients, comprising 34 primary endometrial carcinomas across distinct molecular subtypes (MSI, POLE, p53abn, and NSMP) and four pre-cancerous endometrial intraepithelial neoplasia (EIN) lesions. To stringently control for baseline patient-specific confounding, differential gene expression and principal component analyses were executed using a strict, intra-patient, matched-pair design (Tumor vs. Adjacent Normal). A principal component analysis of the batch-corrected transcriptome revealed a profound divergence between tumor and paired adjacent normal phenotypes. This spatial divergence was heavily characterized by lncRNA signatures (including SOCS2-AS1) strongly associated with extracellular matrix (ECM) remodeling. Concurrently, we identified a critical, malignancy-specific transcriptomic dysregulation across the broader UPS network. Within this altered transcriptional landscape, the ubiquitin C-terminal hydrolase (UCHL) family emerged as a highly significant node. UCHL5 displayed robust, global upregulation across the pan-cancer cohort compared with matched controls (log₂FC = 0.83, padj < 0.001). Strikingly, UCHL3 exhibited global upregulation (log₂FC = 1.23, padj = 0.002) that was highly concentrated within the microsatellite instability (MSI) and polymerase epsilon (POLE) hypermutated subtypes, highlighting a potential compensatory transcriptomic response to the predicted cellular stress inherent to high mutational burdens. In an exploratory subset of pre-cancerous EIN lesions (n = 4), neither the invasive lncRNA networks nor profound UPS/UCHL dysregulation were observed, suggesting a preliminary trend that requires validation in larger precursor cohorts. Our paired transcriptomic mapping reveals that endometrial cancer progression is characterized by divergent transcriptomic programs: specific lncRNA networks are tightly coupled to the invasive remodeling of the ECM, while concurrent dysregulation of broad UPS networks reflects the altered proteostasis associated with this phenotypic shift. The pronounced upregulation of critical UPS nodes, such as UCHL3 in MSI/POLE tumors, highlights a landscape of novel, enzymatically targetable vulnerabilities in hypermutated endometrial cancers. Full article

Background/Objectives: Glutathione S-transferase theta 2 (GSTT2) is highly expressed in esophageal tissues from African American (AA) compared with European American (EA) individuals, but its localization, regulation, and relevance to esophageal adenocarcinoma progression remain unclear. Methods: Here, we combined FISH, immunofluorescence, patient-derived culture models, cell-cycle synchronization, biochemical perturbation, and transcriptomics to define GSTT2 expression in normal and neoplastic esophageal contexts. Results: In developing and adult esophageal tissues, GSTT2 mRNA and protein were broadly distributed across squamous epithelium and lamina propria, co-localizing with p63-positive basal/progenitor cells and extending into differentiated compartments, with no major ancestry-associated differences in spatial patterning. In Barrett’s esophagus, GSTT2 protein was retained in metaplastic columnar epithelium and slightly elevated in dysplastic versus adjacent non-dysplastic regions. GSTT2 mRNA was highest in normal squamous esophagus, reduced during Barrett’s-to-adenocarcinoma progression, but increased in treatment-resistant esophageal adenocarcinoma (EAC). In resistant EAC, GSTT2 co-expression shifted from homeostatic antioxidant programs to proliferation and mitotic pathways, including the G2-M checkpoint, E2F targets, and Reactome Cell Cycle, with leading-edge regulators CDK1 and CDC20. Sequence analysis identified putative APC-C and FBXW7 recognition motifs. In synchronized cells, GSTT2 abundance declined during S-G2/M and increased during mitotic exit/early G1 in cytosolic and membrane fractions. Forskolin, a dual inhibitor of FBXW7 and CDC20, stabilized GSTT2 and rescued CDC20- or FBXW7-associated loss, implicating APC-CDC20 and FBXW7 pathways in GSTT2 turnover. In EAC cells, by contrast, CDC20 was found to be a cooperative partner stabilizing GSTT2. Conclusions: These findings identify GSTT2 as a spatially widespread, ancestry-associated, cell-cycle-regulated protein with potential oncogenic roles in EAC resistance. Full article

Background/Objectives: Papillary thyroid cancer (PTC) is the most common endocrine malignancy and is generally associated with favorable clinical outcomes. However, a subset of tumors develops aggressive phenotypes characterized by increased proliferation, migration, therapeutic resistance, and disease progression. Long non-coding RNAs (lncRNAs) have emerged as important regulators of tumor biology, yet the role of Long Intergenic Non-Protein Coding RNA 1614 (LINC01614) in PTC remains poorly understood. This study investigated the functional role of LINC01614 in PTC and its potential involvement in ferroptosis-associated molecular pathways. Methods: RNA sequencing data from a repository of 44 paired PTC and adjacent normal thyroid tissue samples were analyzed to identify differentially expressed lncRNAs. LINC01614 expression was evaluated in thyroid cell lines, and CRISPR interference (CRISPRi) was used to generate stable LINC01614 knockdown K1 cell lines. Cellular proliferation, migration, clonogenicity, intracellular iron accumulation, lipid peroxidation, cytokine secretion, and ferroptosis-associated gene expression were assessed using qRT-PCR, RNA sequencing, Western blotting, cytokine array analysis, iron quantification assays, and BODIPY C11 lipid peroxidation imaging. Results: LINC01614 was significantly overexpressed in PTC tissues and thyroid cancer cell lines. CRISPRi-mediated repression of LINC01614 reduced cellular proliferation, migration, and clonogenic capacity. Mechanistically, LINC01614 knockdown resulted in an 8.8-fold increase in miR-4521 expression and a 23-fold decrease in IGF2 expression, supporting a potential competing endogenous RNA mechanism. Reduced LINC01614 expression was associated with decreased AKT, GPX4, SLC7A11, and SLC3A2 expression, increased IL-6 secretion, a 3.4-fold increase in intracellular ferrous iron accumulation, and a marked increase in lipid peroxidation following erastin treatment, indicating enhanced sensitivity to ferroptosis. Conclusions: These findings identify LINC01614 as a novel regulator of aggressive PTC phenotypes and ferroptosis resistance. The data support a model in which LINC01614 contributes to thyroid cancer progression through modulation of a miR-4521/IGF2/PI3K/AKT signaling axis and downstream anti-ferroptotic pathways. LINC01614 may represent a promising biomarker and potential therapeutic target in papillary thyroid cancer. Full article

Background/Objectives: Accurate intraoperative identification of the tumor–brain interface is important in brain metastasis surgery, but visual assessment under white light is subjective. Narrow-band imaging (NBI) enhances hemoglobin-dependent optical contrast without an exogenous agent; whether its intraoperative appearance corresponds to tumor tissue, and whether it measurably increases tumor-to-normal image contrast, has not been established in this setting. Methods: In this retrospective, single-center, exploratory study, we evaluated 25 consecutive patients with brain metastases resected using a 4K three-dimensional exoscope equipped with NBI. In three selected patients, spatially adjacent specimens were separately sampled from grayish-appearing and whitish-appearing regions and assessed histopathologically in a non-blinded, descriptive manner. In all 25 patients, paired white-light and NBI images were retrospectively analyzed in Fiji/ImageJ using regions of interest drawn over tissue visually judged to be tumor or normal brain. Results: In the three patients with paired histology, grayish-appearing specimens contained metastatic tumor cells and whitish-appearing specimens did not; this observation derives from a small, selectively sampled subset and should be regarded as preliminary. Across all 25 patients, absolute tumor-to-normal gray-value contrast was significantly greater under NBI than white light (69.628 ± 45.338 vs. 44.287 ± 29.640; mean paired increase, 25.342; 95% CI, 9.169–41.514; p = 0.0035; Cohen’s dz = 0.647), although this increase was not observed in all patients. Conclusions: In this exploratory, non-blinded, retrospective study, NBI increased objective image contrast between visually identified tumor and normal brain relative to white light, and its grayish appearance corresponded to tumor tissue in a small histologically sampled subset. These findings support NBI as a feasible, agent-free adjunct that warrants prospective, blinded validation before its diagnostic accuracy or clinical benefit can be assessed. Full article