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PubMed2025

Extraction, Purification, and Next-Generation Sequencing (NGS) Analysis of DNA and RNA from Formalin-Fixed and Paraffin-Embedded (FFPE) Tissue.

Formalin fixed paraffin embedded (FFPE) tissues have long been used for immunohistological analyses. FFPE tissues can be stored at room temperature for several years enabling analyses to be performed later. Ease of storage and transport makes these tissues an attractive source of biological material. However, formalin fixation results in chemical modifications of proteins and nucleic acids that poses a major challenge to any type of analysis. Recovery of nucleic acids for quantitative assays is rendered difficult due to degradation resulting from fixation and long-term storage, producing low usable yields. Extensive efforts in the last 20 years have led to significant improvements in use of FFPE tissues for DNA and RNA analyses and resulted in development of sensitive assays for a wide range of applications, including next-generation sequencing. In this chapter, we describe the optimization of methods for sequential extraction of DNA and RNA from FFPE tissue and subsequent preparation of DNA-seq and RNA-seq libraries for use with the Illumina platform using commercially available reagents/kits.

Paraffin Embedding↗

PubMed2025

A Study on Differential Proteomics in Differentiated Gastric Adenocarcinoma With Low-grade Atypia Based on Paraffin-embedded Tissues.

In this study, we analyzed and characterized differentially expressed proteins in differentiated gastric adenocarcinoma with low-grade atypia for screening potential protein markers. We collected gastric tissue specimens from 90 patients treated at the Pathology Department of the First People's Hospital of Yunnan Province, China, between January 2019 and December 2022. These specimens had been fixed in 10% neutral-buffered formalin and embedded in paraffin. We classified these samples into 3 groups: the control group (normal gastric mucosa), the low-grade atypia group (differentiated gastric adenocarcinoma with low-grade atypia), and the high-grade atypia group (differentiated gastric adenocarcinoma with high-grade atypia), consisting of 30 cases in each group. We analyzed differential proteomes with the data-independent acquisition-mass spectrometry (DIA-MS) methodology and selected 4 differentially expressed proteins that were subjected to immunohistochemistry (IHC) staining for validation. A total of 4406 proteins were identified, among which 598 and 357 proteins were statistically different in the low-grade atypia group as compared with the control group and the high-grade atypia group, respectively. IHC staining showed that the expression of FHL3, CSRP2, and FCGR3A was significantly higher in the low-grade atypia group than in the control group ( P <0.05) and significantly higher in the high-grade atypia group than in the low-grade atypia group ( P <0.05). FHL2 expression was negative to weakly positive in the control and low-grade atypia groups and not significantly different between the 2 groups, whereas FHL2 expression in the high-grade atypia group was significantly higher than in the control and low-grade atypia groups ( P <0.05). Proteomic analysis is helpful for discovering new protein markers. Using a combination of FHL3, CSRP2, and FCGR3A can increase the accuracy of the pathologic diagnosis of differentiated gastric adenocarcinoma with low-grade atypia.

Humans↗

PubMed2026

Determinants of nucleic acid quality in formalin-fixed paraffin-embedded bladder urothelial carcinoma specimens: effects of specimen type, fixation conditions, and storage time.

Formalin-fixed paraffin-embedded (FFPE) tissue is the principal substrate for cancer genomic profiling, yet pre-analytical factors affect nucleic acid quality. In our workflow, transurethral resection (TUR) specimens of bladder urothelial carcinoma are fixed promptly but exposed to electrocautery, whereas robot-assisted radical cystectomy specimens are refrigerated overnight before fixation; we compared nucleic acid quality between these specimen types. We analyzed 56 FFPE primary bladder urothelial carcinoma specimens (33 TUR, 23 cystectomy). DNA quality was assessed by the DNA Integrity Number (DIN) and short-to-long cycle threshold ratio (S/L Ct ratio), and RNA quality by the RNA Integrity Number (RIN) and percentage of RNA fragments ≥200 nucleotides (DV200), with group comparisons, Spearman correlations, and multivariable regression (specimen type, fixation duration, storage time). The median DIN (4.4 vs. 3.8, p = 0.004) and S/L Ct ratio (0.943 vs. 0.894, p < 0.001) were higher in TUR than cystectomy specimens; the RIN was also higher (1.9 vs. 1.7, p = 0.040), though low in both groups, and DV200 did not differ (50.3% vs. 47.7%, p = 0.934). In multivariable analysis, TUR specimen type independently predicted higher DIN (β = +0.460, p = 0.040) and S/L Ct ratio (β = +0.442, p = 0.009), whereas longer storage time independently decreased the S/L Ct ratio (β = -0.513, p < 0.001) and RIN (β = -0.352, p = 0.010). In our institutional workflow, TUR specimens showed higher DNA quality metrics than robot-assisted radical cystectomy specimens subjected to overnight refrigerated pre-fixation delay, whereas this workflow-associated advantage did not clearly extend to DV200-defined RNA fragment-length quality. Storage time was associated with selected aspects of nucleic acid deterioration.

Humans↗

PubMed2026

Spatial Total RNA Sequencing of Formalin-Fixed Paraffin-Embedded Tissue by spRandom-seq.

The molecular pathogenesis of infectious diseases and cancer is orchestrated by nanoscale of host and microbial RNA transcripts within the tissue microenvironment. Nevertheless, spatially resolving the comprehensive transcriptional landscape within complex clinical tissues, like formalin-fixed paraffin-embedded (FFPE) specimens, still poses a formidable challenge. Here, we present spRandom-seq, a random primer-based spatial total RNA sequencing technology designed to spatially resolve complete transcriptomes from host, bacteria, and even nanoscale viruses in FFPE tissues. Capitalizing on the random primer design, our technology not only facilitated the discovery of specific lncRNAs and alternative splicing events in mouse brain and olfactory bulb, but also delineated pronounced spatial heterogeneity in clinical FFPE sections-across distinct tumor regions in breast cancer and microbial infection sites in Klebsiella pneumoniae-infected tissues. Importantly, integrated analysis of host and viral RNAs in FFPE samples from hepatitis B virus (HBV)‑positive hepatocellular carcinoma (HCC) demonstrated that complement and coagulation pathways were specifically activated across expansive HBV‑infected tumor areas, which also exhibited an increased burden of copy number variations (CNVs). Owing to its compatibility with existing spatial transcriptomics platforms and minimal operational complexity, spRandom-seq represents a practical and scalable approach for clinical pathology applications and infection diagnostics.

Paraffin Embedding↗

PubMed2026

Antibody-Based Proximity Labeling Reveals Bait-Proximal Proteomes in Paraffin-Embedded and Snap-Frozen Tissue Samples.

Proximity-based labeling approaches have proven highly valuable for uncovering protein-protein interactions, yet their application to primary patient material remains challenging. Here, we present a workflow enabling the use of the antibody-based ProtA-Turbo proximity labeling system in both formalin-fixed paraffin-embedded (FFPE) and snap-frozen tissue specimens. Our method efficiently directs biotinylation to diverse antibody baits across tissues of different origins. Downstream mass spectrometry-based proteomics analyses demonstrate the specificity of the method by profiling the proximal proteome of H3K27ac-marked chromatin, the nuclear lamina-associated protein EMD, and the Ser2-phosphorylated POLR2A subunit of RNA polymerase II. Using this method, we identified cell-type-specific factors and transcriptional regulators in salivary gland carcinoma, healthy testis, and testicular cancer tissue sections. The ability to detect disease-associated complexes directly within their native, spatially resolved cellular context using ProtA-Turbo can provide new insights into the molecular basis of human disease and may reveal novel, potentially actionable factors with translational relevance.

Humans↗

PubMed2025

MEG3 Promoter Methylation and F11 Receptor (F11R) Overexpression Define a High-Risk Subtype of Diabetic Pancreatic Cancer.

Long-standing diabetes mellitus (long-DM) (≧3 years) is associated with worse clinical outcomes in patients with pancreatic ductal adenocarcinoma (PDAC). Emerging evidence suggests that epigenetic alterations may contribute to this association; however, the underlying mechanisms remain largely unclear. This study aimed to elucidate the role of the tumor-suppressive long noncoding RNA maternally expressed gene 3 (MEG3) and related molecules in the development of PDAC with long-DM. A total of 117 patients who underwent surgical resection for PDAC at Hirosaki University Hospital were retrospectively analyzed. Histopathological assessment followed World Health Organization criteria and the Union for International Cancer Control tumor-node-metastasis classification. Promoter methylation of MEG3 was assessed via methylation-specific PCR using formalin-fixed paraffin-embedded tissue. MEG3 expression levels were assessed by real-time quantitative PCR. Additionally, proteomic profiling was performed using liquid chromatography-tandem mass spectrometry on formalin-fixed paraffin-embedded tissue samples. Among the 117 cases with PDAC, patients with long-DM exhibited significantly poorer tumor differentiation and reduced cancer-specific survival. MEG3 promoter methylation was more prevalent in patients with long-DM. MEG3 methylation was correlated with reduced MEG3 expression, increased venous invasion, higher recurrence rates, and worse prognosis. Proteomic analysis and protein structure prediction tool revealed F11 receptor (F11R) as a potential downstream effector of MEG3. F11R protein expression levels were evaluated using semiquantitative immunohistochemistry. Higher F11R expression was observed in patients with long-DM, correlating with poor histologic differentiation and unfavorable outcomes. Patients with PDAC showing simultaneous MEG3 methylation and F11R high expression were more likely to have long-DM, with additive effects of these changes and tumor recurrence. Our results demonstrated that MEG3 and its potential downstream regulator, F11R, could be involved in PDAC progression, particularly in patients with long-DM. The findings underscore the clinical significance of epigenetic regulation in DM-related PDAC, suggesting novel targets, such as MEG3 and F11R, for potential therapeutic intervention.

Humans↗

PubMed2026

Targeted sequencing reveals a distinct genetic alteration landscape in oral multiple primary squamous cell carcinomas.

OBJECTIVE: Oral multiple primary cancers (MPCs) are associated with poor clinical outcomes, yet their genomic characteristics remain insufficiently understood. DESIGN: Fifty-four formalin-fixed paraffin-embedded (FFPE) tumor samples from 30 patients with oral MPCs were analyzed using high-depth targeted sequencing of a customized 14-gene panel derived from prior whole-exome sequencing data. Detected alterations were analyzed after removal of synonymous mutations. RESULTS: Non-silent genomic alterations were identified in 59.3% (32/54) of samples, involving 19 patients. A total of 70 variant loci across 13 genes were detected. AKAP13 was the most frequently mutated gene at both the sample (22.2%, 12/54), with recurrent mutations observed across multiple patients. In contrast, TP53 mutations occurred at a substantially lower frequency (11.1%, 6/54). Marked inter- and intra-patient mutational heterogeneity was observed. CONCLUSIONS: FFPE-based targeted sequencing enabled an initial characterization of genomic alterations in oral MPCs. Recurrent alterations in AKAP13, GLI2, JMJD1C, and DNAH8, together with the relatively low frequency of TP53 alterations, identify candidate genomic features for further investigation and provide a basis for future studies of the molecular basis of oral MPCs.

Humans↗

PubMed2024

Molecular characterization of archival adrenal tumor tissue from patients with ACTH-independent Cushing syndrome.

Cushing syndrome represents a multitude of signs and symptoms associated with long-term and excessive exposure to glucocorticoids. Solitary cortisol-producing adenomas (CPAs) account for most cases of ACTH-independent Cushing syndrome (CS). Technological advances in next-generation sequencing have significantly increased our understanding about the genetic landscape of CPAs. However, the conventional approach utilizes fresh/frozen tissue samples, which are not routinely available for most clinical adrenal adenoma specimens. This coupled with the fact that CS is relatively rare reduces the accessibility to CPAs for research. In order to circumvent this issue, our group recently developed a sequencing strategy that allowed the use of formalin-fixed paraffin-embedded (FFPE) CPA samples for mutation analysis. Our streamlined approach includes the visualization and genomic DNA (gDNA) capture of the cortisol-producing regions in the tumor using immunohistochemistry (IHC)-guided techniques followed by targeted and/or whole-exome sequencing analysis. This approach has the advantage of using both prospective and retrospective CPA cohorts since FFPE pathologic specimens are routinely banked. This review discusses this advanced approach using IHC-guided gDNA capture of pathologic tissue followed by NGS as a preferred method for mutational analysis of CPAs.

Humans↗

PubMed2026

Single-cell transcriptomics on FFPE placenta: A novel method for comprehensive exploration of an entire placental section.

INTRODUCTION: The placenta's complex cellular diversity challenges traditional transcriptomic analyses. Single-cell RNA sequencing (scRNA-seq) offers breakthrough capabilities by enabling transcriptome profiling at the single-cell level. However, traditional scRNA-seq relies on fresh or frozen samples, which present practical storage and quality challenges. Applying scRNA-seq to Formalin-Fixed, Paraffin-Embedded (FFPE) placentas could harness archived samples for clinical insights. METHODS: We used 10x Genomics Flex technology to analyze 8 non-pathological placentas ranging from 21 + 6 weeks of gestation (WoG) to 39 + 4 WoG. RESULTS: Our approach identifies diverse cell populations and allows us to discern maternal from fetal cells. Despite sample size limitations, the method yields comparable data to prior fresh/frozen tissue studies and we complete these data by integrating new molecular markers. The potential to correlate single-cell results with histopathology enables us to conduct an in-depth analysis across entire placental sections by concurrently addressing both fetal and maternal cells. We could thus confirm molecular markers like KRT5/6 using immunohistochemistry by revisiting the slide. DISCUSSION: This innovation could aid in understanding focal anomalies observed on standard histology slides, thereby enhancing traditional histopathological assessments. Given its practicality, integrating our method into routine practice is both feasible and promising.

Differentially expressed genes (DEG)↗

PubMed2026

DIA proteomics of FFPE renal biopsies reveals two molecular subtypes of lupus nephritis and identifies APOL1 as candidate biomarker for stratification.

INTRODUCTION: Lupus nephritis (LN) exhibits substantial clinical and pathological heterogeneity. We aimed to define proteomics-based molecular subtypes of LN and identify candidate biomarkers for subtype discrimination. METHODS: We analysed formalin-fixed paraffin-embedded (FFPE) renal biopsy specimens from 292 patients with biopsy-proven LN from four tertiary hospitals using data-independent acquisition (DIA)-liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomics. Molecular subtypes were identified by non-negative matrix factorisation. Differential proteins, functional enrichment, immune pathway activity, protein-protein interaction networks and subtype-associated clinical/pathological features were evaluated. Extreme Gradient Boosting (XGBoost) with SHapley Additive exPlanations (SHAP) and Least Absolute Shrinkage and Selection Operator (LASSO) logistic regression were used to identify key subtype-related features and derive a protein panel distinguishing proliferative (class III/IV) from membranous (class V) LN. RESULTS: Two stable molecular subtypes were identified, with 1002 differential proteins between them. Subtype_2 was enriched for interferon-related innate immunity, complement activation, phagocytosis-endocytosis-lysosome pathways and ribosome biogenesis/RNA metabolism, whereas Subtype_1 was characterised by keratinisation and epithelial structural remodelling. Subtype_2 was associated with higher serum creatinine, lower estimated glomerular filtration rate and higher chronicity index. APOL1 showed discriminatory value between subtypes, and serum ELISA demonstrated a consistent pattern with FFPE proteomic findings. A five-protein LASSO panel achieved an area under the curve of approximately 0.76 for distinguishing class III/IV from class V LN. CONCLUSION: DIA-based proteomic profiling of FFPE renal biopsies identifies biologically and clinically relevant LN molecular subtypes and may support tissue-informed classification and risk stratification.

Humans↗

PubMed2025

Intratumoral fungus Neurospora crassa is associated with worsened prognosis in ovarian cancer via modulation of extracellular matrix.

Landmark studies on intratumoral fungi (ITF) have raised concerns due to irreproducible results and data-analysis errors. We aimed to determine whether ITF exist in ovarian cancer (OvCa) and, if so, whether they play a role in disease biology. Formalin-fixed, paraffin-embedded OvCa samples and multiple controls underwent operational decontamination, qPCR, internal transcribed spacer sequencing, and post-hoc data decontamination. We also leveraged updated fungal reads from The Cancer Genome Atlas generated by the TCMbio group, which addressed human-read contamination and artificial inflation, to validate findings and assess prognostic associations. A murine syngeneic model established using mouse ovarian cancer cell line (OVHM) with intratumoral Neurospora crassa injection was established. Transcriptomic and metabolomic analyses were performed to explore mechanisms. Tumor-containing blocks harbored significantly higher fungal loads than environmental controls but had loads comparable to paraffin controls. Applying a two-pass decontamination filter reduced raw sequence features from 9289 amplicon sequence variants (ASVs) to 659 ASVs. We focused on high-abundance features present in human tissues but absent from xenografts and paraffin controls and identified one candidate, N. crassa, associated with unfavorable prognosis in OvCa. Integrating human and murine data, we found Neurospora correlated with eosinophils, whereas N. crassa itself was not immune-related. Neurospora crassa promoted OvCa progression with downregulation of integrin-linked kinase and decreased extracellular matrix-receptor interaction. Most ITF signals are likely contaminants. We identified N. crassa as associated with unfavorable prognosis in OvCa, potentially via modulation of the extracellular matrix.

Neurospora crassa↗

PubMed2026

Kaposi Sarcoma-Associated Herpesvirus Is Not Detected in Osteosarcoma From KSHV-Endemic African Countries and the Non-Endemic United States Populations.

Osteosarcoma is an aggressive primary malignant bone tumor of poorly defined etiology that predominantly affects adolescents and young adults. A viral cause has long been proposed, and a recent study from Xinjiang, China, reported frequent detection of Kaposi sarcoma-associated herpesvirus (KSHV) in Uyghur osteosarcoma cases, suggesting a possible association in this KSHV-endemic population. Whether this association extends to broader populations remains unknown. Our study investigated the presence of KSHV in osteosarcoma specimens from KSHV-endemic African countries (Cameroon, Kenya, South Africa, Zambia) and the non-endemic United States. A total of 356 formalin-fixed paraffin-embedded and fresh-frozen specimens were retrieved or prospectively collected. In 77 selected high-quality specimens, KSHV infection was assessed by immunohistochemistry for LANA1 and by qPCR targeting 5 viral open reading frames (ORF25, ORF26, ORF37, ORF65, and ORF73). LANA1 expression was undetectable in all tumors. Using qPCR, 75/77 specimens were negative for all targets, 1/77 excluded due to insufficient remaining DNA quantity to perform the assay, and 1/77 positive across all five targets. Additionally, we studied the KSHV seroprevalence in a separate cohort comprised of 49 sera obtained from individuals with osteosarcoma from Zambia (n = 39) and the United States (n = 10). We measured by ELISA the presence of specific antibodies against four KSHV antigens: K8.1, KCP, VCA, and LANA1. KSHV seropositivity was detected in 15/39 individuals from Zambia and none from the United States. In the absence of compelling evidence, our findings could not support an association between KSHV infection and osteosarcoma in our study population.

Humans↗

PubMed2025

Simultaneous Visualization of Protein and Genomic Regions in Plant Nuclei.

Immunohistostaining (IHS) is a widely used technique in diagnostic and research laboratories in which specific antibodies are used to detect and visualize a protein of interest in cells or tissues. Similarly, with specific oligonucleotide probes, the fluorescence in situ hybridization (FISH) method allows one to visualize genomic regions and to analyze its localization in the nuclear space. Here, we describe a combined FISH-IHS technique that enables researchers to determine the localization of protein and genomic loci in plant nuclei simultaneously. This method can be applied to extracted nuclei and sections of paraffin-embedded tissues. It provides a valuable tool to improve our understanding of nuclear dynamics by revealing the spatial relationship between specific genomic loci and target proteins.

In Situ Hybridization, Fluorescence↗

PubMed2026

Clinically actionable genomic alterations in breast cancer brain metastases.

BACKGROUND: Breast cancer brain metastases (BCBMs) represent a critical unmet clinical need in metastatic breast cancer (MBC) and the identification of novel therapeutic targets is urgently needed in this context. In this study, we describe clinically actionable targets in BCBMs using comprehensive genomic profiling. PATIENTS AND METHODS: Genomic DNA was extracted from formalin-fixed paraffin-embedded archival BCBM samples and analyzed using the commercially available Agilent SureSelect V6 whole exome sequencing (WES) kit and an Illumina NovaSeq 6000 platform. Pathogenic alterations were classified as actionable alterations (AAs) if they met the updated MBC or tumor-agnostic ESMO Scale for Clinical Actionability of Molecular Targets (ESCAT) I or II criteria of the ESCAT scale. RESULTS: WES data from 56 BCBM samples were available [33.9% hormone receptor (HR)-negative/human epidermal growth factor receptor (HER)2-negative; 25.0% HR-positive/HER2-negative; and 38% HER2-positive]. ESCAT I/II AAs were detected in 76.8% (n = 43) of all BCBMs and the most frequently detected AAs were in genes involved in the homologous recombination repair pathway (BRCA1/BRCA2/PALB2; 53.6% overall). Biallelic inactivation of BRCA1, BRCA2, or PALB2 was observed in 19.6% of samples, with higher rates in HER2-negative BCBMs (26% in HR-negative /HER2-negative and 21% in HR-positive/HER2-negative). ESCAT I/II PIK3CA/AKT1/PTEN pathway alterations were present in 48.2% of samples and, in particular, in 50% of HR-positive/HER2-negative BCBMs. No ESR1 mutation was detected in HR-positive/HER2-negative BCBMs. The prognostic impact of previously described AAs was evaluated overall and according to breast cancer subtype. Twenty-three BCBMs (41%) were classified as HER2-positive; among these, 3 (13%) presented a hotspot PIK3CA mutation and 7 (30%) presented a PTEN deletion. Among patients with HER2-positive BCBMs, the identification of a hotspot PIK3CA mutation was significantly associated with worse prognosis. CONCLUSIONS: ESCAT I/II actionable genomic alterations are frequent in BCBMs, highlighting the potential for genomically targeted treatments in this setting.

ESCAT↗

PubMed2026

Prevalence of homologous recombination repair genes alterations in metastatic castration-resistant prostate cancer, a multicentric study.

INTRODUCTION: Homologous Recombination Repair (HRR) genes alterations are a resistance mechanism to therapies by taxanes or Androgen Receptor Signalling inhibitors in Metastatic Castration Resistant Prostate Cancer (mCRPC). BRCA-mutated mCRPC patients are eligible to poly adenosine diphosphateribose polymerase inhibitors (PARPi). Therefore, assessing the population-specific prevalence of HRR-related genes alterations is of public healthcare importance. METHODS: This retrospective, non-interventional, multicentric study was conducted across 6 reference French centers in a "real-life" setting. 788 paraffin-embedded mCRPC patient-samples were included and submitted to testing for BRCA1/2 in six different centers; additionally, non-BRCA HRR-related genes were investigated in two different centers. RESULTS: Among the samples, n=602 (76.4%) were contributive for molecular testing. In multivariate analysis by logistic regression and sensitivity analysis, only sample age (P<0.01), sample surface area (P=0.02) and institution (P=0.018) remained statistically significant. BRCA alterations were detected in n=39/602 (6.5%) of contributive samples, with n=35 and n=4 alterations of BRCA2 and BRCA1 respectively. Non-BRCA HRR-related genes alterations were detected in n=12/157 (7.6%) of contributive samples, with alterations of mainly ATM (n=6, 3.8%), CDK12 (n=4, 2.5%) and CHEK2 (n=2, 1.3%). DISCUSSION: In this study, testing contributivity was similar or higher that of other studies in the literature, and observed mutations prevalences were similar to that of other screenings of western populations. Harmonising per-centres protocols and enhancing molecular testing contributivity with the screening of circulating DNA samples and expanding its range by including non-BRCA HRR-related genes in all reference centres will enable more patients to be accurately treated by targeted therapies. LEVEL OF EVIDENCE: 3 (grade C).

Male↗

PubMed2026

Genome-Wide Single-Nucleotide Polymorphism (SNP)-based Profiling of Loss of Heterozygosity Reveals Distinct Molecular Subgroup-Specific Patterns in Gastrointestinal Stromal Tumors (GIST).

PURPOSE: Gastrointestinal stromal tumors (GIST) are molecularly heterogeneous neoplasms defined by mutually exclusive driver alterations (KIT, PDGFRA, SDH, BRAF, RAS, and NF1). However, driver mutations alone do not fully explain their biological and clinical variability. Chromosomal imbalances and loss of heterozygosity (LOH) may represent an additional layer of tumor characterization. We developed a single-nucleotide polymorphism (SNP)-based next-generation sequencing panel enabling genome-wide LOH assessment from formalin-fixed paraffin-embedded tissue. MATERIALS AND METHODS: Forty-nine GIST cases molecularly classified using targeted next-generation sequencing (KIT n = 19, PDGFRA n = 9, SDH-deficient n = 8, NF1 n = 7, quadruple wild-type n = 6) were analyzed. LOH was inferred from variant allele frequency patterns across 1826 genome-wide SNPs. RESULTS: Chromosome 14 was the most commonly affected (63%), followed by chromosomes 22 (45%), 15 (41%), 21 (27%), and 13 (20%). Loss of chromosome arm 1p occurred in 43% of tumors. Distinct subgroup-specific patterns emerged: KIT-mutant GIST exhibited the highest degree of genomic instability, whereas both SDH-deficient tumors and PDGFRA-mutant GIST displayed minimal chromosomal instability. NF1-mutant tumors showed recurrent single-arm chromosome 17 LOH. Quadruple wild-type GISTs were heterogeneous, including 1 case with extensive chromosomal instability. CONCLUSIONS: Genome-wide SNP-based LOH profiling reveals distinct, subgroup-specific patterns of chromosomal imbalance in GIST and may serve as a feasible complementary approach to driver mutation analysis for refined molecular characterization and potential future clinical utility.

Humans↗

PubMed2024

Combining Data Independent Acquisition With Spike-In SILAC (DIA-SiS) Improves Proteome Coverage and Quantification.

Data-independent acquisition (DIA) is increasingly preferred over data-dependent acquisition due to its higher throughput and fewer missing values. Whereas data-dependent acquisition often uses stable isotope labeling to improve quantification, DIA mostly relies on label-free approaches. Efforts to integrate DIA with isotope labeling include chemical methods like mass differential tags for relative and absolute quantification and dimethyl labeling, which, while effective, complicate sample preparation. Stable isotope labeling by amino acids in cell culture (SILAC) achieves high labeling efficiency through the metabolic incorporation of heavy labels into proteins in vivo. However, the need for metabolic incorporation limits the direct use in clinical scenarios and certain high-throughput experiments. Spike-in SILAC (SiS) methods use an externally generated heavy sample as an internal reference, enabling SILAC-based quantification even for samples that cannot be directly labeled. Here, we combine DIA-SiS, leveraging the robust quantification of SILAC without the complexities associated with chemical labeling. We developed DIA-SiS and rigorously assessed its performance with mixed-species benchmark samples on bulk and single cell-like amount level. We demonstrate that DIA-SiS substantially improves proteome coverage and quantification compared to label-free approaches and reduces incorrectly quantified proteins. Additionally, DIA-SiS proves effective in analyzing proteins in low-input formalin-fixed paraffin-embedded tissue sections. DIA-SiS combines the precision of stable isotope-based quantification with the simplicity of label-free sample preparation, facilitating simple, accurate, and comprehensive proteome profiling.

Isotope Labeling↗

PubMed2026

Simultaneous quantitative detection of multiple low-frequency variants by high-dynamic-range capillary electrophoresis.

Sensitive and quantitative detection of low-frequency variants across multiple loci is critical for nucleic acid-based diagnostics, yet clinical implementation requires a balance among sensitivity, multiplexing capacity, cost, and operational simplicity. We previously developed a high-dynamic-range capillary electrophoresis system capable of detecting variants at allele frequencies below 1%; however, its application was limited to single-locus analysis. Here, we expanded this platform to multiplex detection by incorporating mobility-shift strategies into the assay design. This approach enabled simultaneous analysis of 15 hotspot variants across three clinically relevant loci: KRAS codons 12 and 13 and GNAS codon 201. Validation using synthetic oligonucleotides, formalin-fixed paraffin-embedded tissue, and liquid specimens demonstrated high quantitative accuracy over clinically relevant variant allele frequency ranges, with measured values closely matching expected values (R2 > 0.97). The assay showed high concordance with targeted amplicon sequencing and digital polymerase chain reaction for all variants at variant allele frequencies ≥1%, while also detecting selected variants below this threshold. Collectively, these results establish a multiplexed high-dynamic-range capillary electrophoresis assay for simultaneous, quantitative detection of low-frequency variants, offering a scalable and cost-effective approach for disease-focused gene panels in clinical laboratory settings.

HiDy↗