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Dynamic allelic expression in mouse mammary glands across the adult developmental cycle.

The mammary gland, which primarily develops postnatally, undergoes significant changes during pregnancy and lactation to facilitate milk production. Through the generation and analysis of 480 transcriptomes, we provide the most detailed allelic expression map of the mammary gland, cataloguing cell-type-specific expression from ex-vivo purified cell populations over 10 developmental stages, enabling comparative analysis. The work identifies genes involved in the mammary gland cycle, parental-origin-specific and genetic background-specific expression at cellular and temporal resolution, genes associated with human lactation disorders and breast cancer. Genomic imprinting, a mechanism regulating gene expression based on parental origin, is crucial for controlling gene dosage and stem cell potential throughout development. The analysis identified 25 imprinted genes monoallelically expressed in the mammary gland, with several showing allele-specific expression in distinct cell types. No novel imprinted genes were identified and the absence of biallelically expressed imprinted genes suggests that, unlike in brain, selective absence of imprinting does not regulate gene dosage in the mammary gland. This research highlights transcriptional dynamics within mammary gland cells and identifies novel candidate genes potentially significant in the tissue during pregnancy and lactation. Overall, this comprehensive atlas represents a valuable resource for future studies on expression and transcriptional dynamics in mammary cells.

Animals↗

Transcriptome analysis documents induced competence of Bacillus subtilis during nitrogen limiting conditions.

DNA microarrays were used to analyze the changes in gene expression in Bacillus subtilis strain 168 when nitrogen limiting (glutamate) and nitrogen excess (ammonium plus glutamate) growth conditions were compared. Among more than 100 genes that were significantly induced during nitrogen starvation we detected the comG, comF, comE, nin-nucA and comK transcription units together with recA. DNA was added to B. subtilis grown in minimal medium with glutamate as the sole nitrogen source and it was demonstrated that the cells were competent. Based on these observations we propose a simplification of previously designed one-step transformation procedures for B. subtilis strain 168.

Bacillus subtilis↗

A contextual activity score (CAS) for inferring ADAR-associated transcriptional activity across RNA-seq, single-cell, and spatial transcriptomics.

BACKGROUND AND OBJECTIVE: Adenosine-to-inosine RNA editing, catalyzed by Adenosine Deaminases Acting on RNA (ADARs), is a widespread modification involved in neural function, immune regulation, and cancer. The Alu Editing Index (AEI) is the standard metric to estimate ADAR activity but requires raw sequencing reads and is poorly suited for single-cell and spatial transcriptomic data. This study aimed to develop an alternative framework for inferring ADAR-associated transcriptional activity from gene expression data across diverse transcriptomic technologies. METHODS: We developed the Contextual Activity Score (CAS), a framework based on transcriptional signatures from ADAR perturbation experiments. Context-specific signatures were generated for human neurons, mouse neurons, and cancer models to infer ADAR1 and ADAR2 activity. CAS was computed from normalized gene expression matrices using regulon-based enrichment analysis. Performance was evaluated by comparing with the Alu Editing Index across bulk RNA sequencing datasets, simulated sequencing depths, and library preparation protocols. RESULTS: CAS showed strong concordance with the Alu Editing Index across multiple datasets, while remaining robust to reduced sequencing depth and different library protocols. Unlike the Alu Editing Index, CAS can be applied to single-cell and spatial transcriptomic data and enables the independent assessment of ADAR2 activity. In cancer and neuronal contexts, CAS captured biologically meaningful variations in ADAR-associated transcriptional activity at sample, cell-type, and spatial levels. CONCLUSION: CAS provides a scalable approach applicable across multiple RNA-seq protocols for estimating ADAR-associated transcriptional activity using gene expression data. This method, implemented in an open-source R package for broad adoption, expands the ability to study ADAR-associated transcriptional activity across transcriptomic modalities where direct editing quantification is challenging, such as single-cell and spatial transcriptomics.

Adenosine Deaminase↗

Single-cell transcriptomics reveals that air-liquid interface culture promotes goblet cell differentiation and inhibits glycolysis in organoid cell monolayers.

Faithfully recapitulating the cellular heterogeneity of the intestinal epithelium is essential when using organoid models. Air-liquid interface (ALI) culture has been shown to promote secretory cell differentiation, but its impact on gene expression in each epithelial cell type remains unclear. In this study, we used single-cell RNA sequencing (scRNA-seq) to characterize the cellular heterogeneity of rabbit cecum-derived organoid monolayers grown under immerged or ALI conditions. We then compared these organoid cell type-specific gene expression profiles to a scRNA-seq atlas of the rabbit cecal epithelium in vivo. We selected the rabbit model notably because, unlike mice, it possesses BEST4+ epithelial cells, a newly discovered subset of mature absorptive cells. Our analysis revealed a high degree of transcriptomic similarity between in vivo and organoid-derived stem and transit-amplifying cells. ALI culture markedly enhanced the differentiation of the secretory lineage, especially goblet cells, whose transcriptome closely resembled that of in vivo goblet cells. Furthermore, ALI was the only condition allowing the detection of enteroendocrine cells. BEST4+ cells, however, were absent from organoids in immerged or ALI conditions despite their presence in vivo. In addition, ALI culture led to a consistent downregulation of hypoxia and glycolysis-associated genes across all cell types, which suggests a metabolic shift likely driven by increased oxygen availability in ALI conditions. Cell-cell communication analyses further indicated that ALI more closely mirrored in vivo patterns than immerged condition. Altogether, these results demonstrate that ALI culture allows for better recapitulation of the in vivo cellular heterogeneity and molecular signatures of the intestinal epithelium.NEW & NOTEWORTHY Using single-cell RNA sequencing, this study shows that air-liquid interface (ALI) culture enhances secretory lineage differentiation of intestinal organoid cell monolayers and improves transcriptomic similarity to the native epithelium. ALI reduced hypoxia-associated gene expression and better recapitulates in vivo-like cell-cell interactions, supporting its value for modeling intestinal epithelial heterogeneity in organoids.

Animals↗

Evolutionary and resistance dynamics in oligometastatic and oligoprogressive cancer treated with stereotactic radiotherapy and systemic therapies: A systematic review and focused meta-analysis.

BACKGROUND: Oligometastatic and oligoprogressive disease treated with stereotactic ablative radiotherapy (SABR) represents a clinically heterogeneous entity. Increasing evidence suggests that anatomical definitions alone may not adequately capture underlying biological diversity. This systematic review aimed to synthesize translational evidence exploring evolutionary dynamics, resistance mechanisms, and biomarker-driven stratification in patients treated with SABR. METHODS: A systematic literature review was performed including prospective and retrospective studies evaluating translational biomarkers in oligometastatic or oligoprogressive settings treated with SABR. Studies assessing genomic, transcriptomic, circulating or immune-related biomarkers were included. Data were summarized qualitatively according to predefined translational domains: (i) evolutionary dynamics under systemic therapy pressure, (ii) baseline biological stratification, (iii) longitudinal circulating biomarkers, and (iv) systemic immune remodeling. Exploratory quantitative visual syntheses were performed using reported hazard ratios when conceptually comparable endpoints were available. RESULTS: 19 studies comprising 1527 patients were included. Across tumor types and treatment contexts, translational analyses consistently indicated that anatomically defined oligometastatic states encompass biologically distinct subgroups with different risks of systemic progression. Studies evaluating oligoprogression under ongoing systemic therapy suggested a distinction between spatially constrained resistance and systemic molecular escape, supported by circulating tumor DNA and tissue- or plasma-based molecular profiling (including genomic and transcriptomic analyses). Baseline biological features, including adverse genomic signatures and circulating biomarkers, were associated with inferior progression outcomes despite metastasis-directed therapy. Longitudinal biomarkers provided early signals of treatment response and systemic control. Immune remodeling after SABR showed context-dependent effects, both systemic immune activation and treatment-related immunosuppression reported across studies.

Humans↗

A regulatory network underlying idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease in which genetic susceptibility interacts with epithelial, immune, and mesenchymal remodeling. Although the chromosome 11p15.5 locus contains established IPF susceptibility signals near MUC5B and TOLLIP, the broader regulatory architecture of this region remains incompletely resolved. METHODS: We integrated IPF genome-wide association study summary statistics with methylation, expression, and protein quantitative trait loci using summary-data-based Mendelian randomization (SMR). SMR-prioritized candidates were evaluated in independent transcriptomic and methylation cohorts and further contextualized using microRNA, transcription-factor, protein-interaction, machine-learning, single-cell, and spatial transcriptomic analyses. Fibrosis-associated expression patterns were assessed in a bleomycin-induced pulmonary fibrosis rat model. RESULTS: The analyses recovered the established MUC5B and TOLLIP signals and prioritized BRSK2 as a comparatively underexplored candidate supported by eQTL-based SMR and independent molecular evidence. The BRSK2 pQTL association did not pass the HEIDI test and was therefore not interpreted as convergent protein-level genetic evidence. Network analyses linked BRSK2 to cell-cycle, metabolic-stress, and senescence-related programs, while cross-cohort machine learning prioritized FOXA2, CDC25B, and NFE2 as informative network features. Single-cell and spatial analyses localized BRSK2 preferentially to fibroblast and myofibroblast compartments and to regions with greater histological fibrosis severity. In fibrotic rat lungs, BRSK2 expression increased, whereas FOXA2 and CDC25B decreased at the transcript and protein levels. CONCLUSIONS: These findings refine the molecular landscape of the chromosome 11p15.5 IPF susceptibility locus and prioritize BRSK2 as a candidate component of an IPF-associated profibrotic fibroblast state. Its causal contribution, direct regulatory relationships, and therapeutic tractability require targeted mechanistic validation.

Idiopathic Pulmonary Fibrosis↗

Unveiling the genetic basis of the low pH response in the acidophilic yeast Maudiozyma bulderi as a potential host for biorefinery.

Nonconventional yeasts represent a great genetic and phenotypic diversity with potential for industrial strain development in the bio-production of green chemicals. In recent years, mass genome sequencing of nonconventional yeasts has opened avenues to improved understanding of transcriptional networks and phenotypic plasticity and gene function, including the discovery of novel genes. Here, we investigated the expressional and morphological changes at low-pH in three strains of the acidophilic yeast Maudiozyma bulderi (previously Kazachstania bulderi and Saccharomyces bulderi): CBS 8638, CBS 8639, and NRRL Y-27205. The comparison of the transcriptome of cells growing in a bioreactor at pH = 5.5 vs pH = 2.5, primarily showed dysregulation of genes involved in cell wall integrity, with NRRL Y-27205 the least acidophilic strain, showing the largest transcriptional response when compared to the other strains. We identified four uncharacterized genes, unique to M. bulderi, and predicted function as transporters, upregulated at low pH. Microscopy studies showed that M. bulderi cell wall is not damaged in acidic environment, and the membrane lipid composition remains stable at low pH, unlike Saccharomyces cerevisiae. Overall, our data on transcriptional variability in M. bulderi highlights genes and cellular pathways involved in the acidophilic adaptation of this species and can aid further strain development.

Hydrogen-Ion Concentration↗

Genomic and molecular landscape of early onset colorectal cancer: Emerging insights and clinical implications-A systematic review.

BACKGROUND: Early onset colorectal cancer, defined as colorectal malignancy occurring before age 50, has been rising globally. Increasing molecular evidence suggests that early onset colorectal cancer is not merely a premature form of late-onset colorectal cancer but a distinct biologic entity with unique genomic and transcriptomic profiles. METHODS: A systematic PubMed search using the terms "early onset colorectal cancer," "genomic," and "molecular" identified 270 records. Eighteen original studies met the inclusion criteria and were supplemented by references from selected articles. Extracted data encompassed clinicopathologic characteristics, genomic and epigenetic alterations, and dysregulated signaling pathways distinguishing early onset colorectal cancer from late-onset colorectal cancer. RESULTS: Evidence from approximately 19,888 patients with early onset colorectal cancer was synthesized across genomic, transcriptomic, and clinical data sets. Early onset colorectal cancer showed a predominance in distal and rectal sites, a slight male bias, and a higher prevalence among Hispanic and Asian populations. Compared with late-onset colorectal cancer, early onset colorectal cancer exhibited lower B-Raf proto-oncogene, serine/threonine kinase V600E mutation and CpG island methylator phenotype-high methylation frequencies but higher rates of tumor protein p53, Kirsten rat sarcoma viral oncogene homolog, and DNA-repair gene alterations. Distinct comutation patterns (F-box and WD repeat domain containing 7-neurogenic locus notch homolog protein 3-phosphoinositide-3-kinase regulatory subunit 1 and adenomatous polyposis coli-tumor protein p53) and overexpression of immediate-early response genes (Proto-Oncogene c-Fos, EGR1, DUSP1, and CYR61) defined its transcriptional landscape. Perturbations of Wingless/Integrated signaling pathway, mitogen-activated protein kinase, phosphoinositide 3-kinase-protein kinase B-mechanistic target of rapamycin, and DNA-repair pathways, along with global long interspersed nuclear element-1 hypomethylation, indicated heightened genomic instability. CONCLUSION: Early onset colorectal cancer develops through tumor protein p53-driven genomic instability and defective DNA repair rather than the canonical CpG island methylator phenotype-B-Raf proto-oncogene, serine/threonine kinase axis. Recognition of these molecular distinctions is essential for age-specific risk assessment, screening, and precision therapeutics. Further integrative studies are needed to elucidate environmental and genetic contributors and identify novel biomarkers and treatment targets.

Humans↗

Large-scale analysis of the human and mouse transcriptomes.

High-throughput gene expression profiling has become an important tool for investigating transcriptional activity in a variety of biological samples. To date, the vast majority of these experiments have focused on specific biological processes and perturbations. Here, we have generated and analyzed gene expression from a set of samples spanning a broad range of biological conditions. Specifically, we profiled gene expression from 91 human and mouse samples across a diverse array of tissues, organs, and cell lines. Because these samples predominantly come from the normal physiological state in the human and mouse, this dataset represents a preliminary, but substantial, description of the normal mammalian transcriptome. We have used this dataset to illustrate methods of mining these data, and to reveal insights into molecular and physiological gene function, mechanisms of transcriptional regulation, disease etiology, and comparative genomics. Finally, to allow the scientific community to use this resource, we have built a free and publicly accessible website (http://expression.gnf.org) that integrates data visualization and curation of current gene annotations.

Animals↗

Molecular and immune profiling of HER2-low, HER2 ultra-low, and HER2-null male breast cancer.

BACKGROUND: HER2 expression is described along a biological continuum from null to positive and serves as a critical biomarker for therapeutic guidance in breast cancer (BC). While HER2-low and ultra-low categories have emerged as actionable targets for antibody-drug conjugates (ADCs) in female BC, their molecular and immune characteristics remain largely unexplored in male breast cancer. METHODS: We profiled 214 male breast tumors using next-generation sequencing and whole-transcriptome sequencing to assess mutational, transcriptomic, and immune landscapes. Tumor mutational burden (TMB) was defined as high if > 10 mutations/Mb. Immune cell fractions were inferred using Quantiseq deconvolution. RESULTS: Among 214 samples, 66 (30.8%) were HER2-null, 53 (24.8%) HER2 ultra-low, 80 (37.4%) HER2-low, and 15 (7.0%) HER2-positive. HER2 ultra-low tumors exhibited a higher prevalence of PIK3CA mutations (39.2% vs 22.6%, p ≤ 0.05) compared to HER2-null. No significant differences were observed in TMB-high frequency or PD-L1 expression across subgroups. Immune composition differed primarily between HER2-null and HER2-expressing subgroups: HER2-ultra-low tumors showed higher B-cell infiltration, whereas HER2-null tumors were enriched in neutrophils. Transcriptomic analysis revealed upregulation of selected stemness-associated genes (NANOG, KLF4, POU5F1) and CEACAM1 in HER2-null tumors, while HER2-low and HER2-ultra-low tumors were largely similar across most molecular and immune readouts in this cohort. CONCLUSIONS: HER2-null male breast cancer appears to represent the most biologically divergent subgroup within the HER2-negative spectrum, whereas HER2-low and HER2-ultra-low tumors were largely similar in this cohort. These findings support further investigation of HER2-null disease as a distinct biological state and provide hypothesis-generating data for biomarker development in this rare population.

Male↗

Distinct cell morphotypes of Aureobasidium melanogenum ZN exhibit differential functional profiles in promoting maize growth.

Black yeast-like fungi of the genus Aureobasidium exhibit morphological plasticity, but whether distinct cellular states within the same genetic background are associated with different plant growth-promoting functions remains unclear. Here, yeast-like cells (YL), swollen cells (SC), and chlamydospores (CH) of Aureobasidium melanogenum ZN were characterized. YL was associated mainly with siderophore production and laccase activity, SC with extracellular polysaccharide accumulation, and CH with phosphate mobilization and higher ammonia and IAA production. Whole-genome and comparative genomic analyses revealed a shared repertoire related to nutrient acquisition, auxin-associated metabolism, extracellular oxidation, and carbohydrate remodeling, with expansions in nutrient- and cell-surface-related gene families. Transcriptomic and metabolomic analyses showed distinct deployment of these capacities, with CH exhibiting broad reprogramming of tryptophan-associated, nitrogen, phosphate, central-carbon, and amino-acid metabolism. In maize, CH at the optimal inoculation concentration of 105 CFU·mL-1 produced the strongest growth promotion, increasing plant height, dry biomass, root length, root surface area, and root volume by 58.6%, 365.1%, 191.0%, 194.3%, and 222.4%, respectively. Consistent with this pronounced growth phenotype, maize root transcriptomics showed coordinated CH-induced responses involving root development, nutrient transport, redox regulation, and root-interface remodeling. Root-zone tracking showed greater short-term stability and persistence of CH. These findings identify cellular state as an important functional dimension of Aureobasidium-plant interactions and provide a basis for developing fungal inoculants with defined beneficial cellular states.

Zea mays↗

Blood Bile Acids for Inflammatory Bowel Disease Diagnosis and Disease Activity Assessment: A Metabolomics Meta-Analysis.

Alterations in circulating bile acids (BAs) have been reported in inflammatory bowel disease (IBD), but the consistency of these changes across clinically relevant comparisons remains unclear. Our goal was to investigate systemic BA alterations in IBD using a metabolomics meta-analysis with an exploratory analysis of BA-related gene expression as a supporting context. A systematic review and meta-analysis of 28 metabolomics studies examined blood BA profiles associated with IBD, IBD diagnosis, and disease activity assessment. Univariate analysis and logistic regression modeling of two independent IBD cohorts explored the blood BA-related genes and IBD. Across 28 studies that comprised 5056 IBD patients, 1721 healthy controls, and 314 non-IBD patients, 131 BAs were reported. Eight predefined clinical comparisons were eligible for the meta-analysis. Lower secondary BA levels were consistently observed in IBD patients compared with controls, between UC and CD, and in active versus remission patients. Deoxycholic acid, glycodeoxycholic acid, and taurodeoxycholic acid were frequently decreased, whereas glycocholic acid was increased in certain comparisons. Transcriptomics analyses revealed differential expression of several BA-related genes in blood, including SLC51A, ABCB4, and ACOT8, across the comparisons. Our findings identify consistent circulating BA alterations in IBD and highlight the relevance of blood BA for future biomarker research in the diagnosis and disease activity assessment.

Humans↗

Molecular neuropathology of transgenic mouse models of Down syndrome.

Down syndrome (DS) is a complex, clinically heterogeneous disorder which shows both impairment of neurodevelopement and the neurodegenerative changes of Alzheimer's disease (AD). The phenotype of DS is caused by triplication of chromosome 21 and transgenic mouse models have been developed, and are being created, that carry single genes and chromosomal segments to excess. For example, transgenic mice containing additional copies of the amyloid precursor protein (APP) gene, have been useful in producing the Abeta deposition characteristic of AD and DS, but not the cytoskeletal changes that are the hallmarks of these human disorders. Such models are useful in replicating aspects of pathogenesis and allow for the testing of therapeutic agents to restore impaired function. Segmental trisomic mouse models, which survive to adulthood and possess three copies of multiple genes responsible for the DS phenotype, such as Ts1Cje and Ts65Dn, have been used to explore aspects of neurodevelopment and neurodegeneration. These animal models show some but not all the pathological, biochemical, and transcriptional changes seen in DS. They also have the advantage of allowing for the testing of therapeutic agents to restore impaired function. Analysis of the transcriptome and proteome of fetal and adult DS indicates that there is a complex relationship between gene dosage, gene and protein expression, and that data from animal models will need to be compared and evaluated in the light of data obtained from DS tissue.

Animals↗

A critical appraisal of base-resolution m6A profiling techniques.

N6-methyladenosine (m6A) is the most prevalent internal modification in eukaryotic mRNA, influencing RNA fate and gene regulation. Early antibody-based approaches enabled transcriptome-wide profiling but lacked resolution and quantitative accuracy. Newer approaches now achieve base-resolution m6A detection using improved crosslinking, chemical or enzymatic conversion, and single-molecule sequencing. Antibody-free methods provide quantitative stoichiometry from minimal input, while nanopore direct RNA sequencing offers real-time, single-molecule readouts across entire transcriptomes. Collectively, these methods form a versatile toolkit that integrates global mapping with precise site-level analysis, advancing knowledge of context-dependent m6A regulation in physiology and disease. This review compares their principles, strengths, and limitations to guide method selection and highlight how next-generation epitranscriptomic tools are paving the way for clinical and therapeutic applications.

Humans↗

GRNContext: an interactive web platform for contextualized gene regulatory networks visualization across human cancers.

SUMMARY: While current Gene Regulatory Network (GRN) databases provide comprehensive reference maps of potential interactions between transcription factors and target genes, they do not specify which regulatory interactions are active within specific biological contexts. This limitation is particularly critical in cancer, where transcriptional programs are inherently tissue-specific. To address this gap, we developed GRNContext, an interactive web platform designed for the visualization, exploration, and comparative analysis of gene regulatory networks contextualized across 33 cancer types from The Cancer Genome Atlas (TCGA). Our approach uses the TFLink human reference GRN as a starting point and integrates TCGA transcriptomic profiles to infer cancer-specific regulatory activity. Regulatory relevance was assessed using complementary machine learning and statistical methods, which were unified into a consensus score to prioritize and filter the most relevant candidate regulators for each target gene. By providing both curated context-specific GRNs and a user-friendly platform, GRNContext constitutes a comprehensive and accessible resource that supports mechanistic investigations, hypothesis generation, and translational research focused on transcriptional regulation in cancer. AVAILABILITY AND IMPLEMENTATION: GRNContext is supported by all major browsers and freely available on the web at https://apps.cienciavida.org/grncontext. It is implemented as a client-server web application featuring a FastAPI backend and a React frontend utilizing Cytoscape.js for interactive network visualization, all containerized via Docker for cross-platform compatibility.

Humans↗

Inheritance of the epigenetic signature and reduced intermuscular bone phenotype acquired via DNA methylation editing of the runx2 b promoter in zebrafish.

The presence of intermuscular bones (IBs) can directly affect the economic value of aquaculture fish. Although genome editing can create IB-free fish by knocking out key IB-related genes, such as runx2b, the associated DNA sequence alterations raise food safety and health concerns, limiting its breeding applications. In this study, we used CRISPR/dCas9-mediated epigenome-editing technology targeting the runx2 b promoter in zebrafish to alter DNA methylation patterns without changing the DNA sequence. Our results showed that higher runx2 b promoter methylation patterns significantly inhibited eGFP mRNA expression levels in the recombinant plasmid. Using the CRISPR/dCas9-Dnmt7 system to enhance methylation of the zebrafish runx2b promoter, we observed a significant decrease in runx2 b mRNA expression levels in the F0 generation. The IBs in the 11 th-16 th muscle segments of the adult F0 fish were significantly shorter compared with the controls. Inbreeding of fish was used to produce F1 and F2 offspring that retained these high promoter methylation levels, along with persistent runx2b expression suppression and IB development inhibition. Transcriptome sequencing analysis suggested that increasing runx2 b promoter methylation levels may synergistically induce additional epigenetic modifications, potentially affecting the PPAR signaling pathway and FoxO transcription factor regulation, which appears to inhibit osteoblast proliferation and differentiation. Overall, this study demonstrates an innovative application of epigenetic editing technology for aquaculture breeding. By precisely regulating the expression patterns of key genes for economically important traits while preserving genomic DNA integrity, this approach provides a theoretical foundation and technical support for improving fish economic traits.

Animals↗

Genomic, transcriptomic, and molecular predictors of response to neoadjuvant therapy in locally advanced rectal cancer: a narrative review.

Total neoadjuvant therapy (TNT) has emerged as a key treatment paradigm for locally advanced rectal cancer, reducing distant metastasis rates and facilitating organ preservation in selected patients. However, treatment response remains heterogeneous, highlighting the need for biomarkers that can guide treatment selection and optimise outcomes. This narrative review synthesises the current evidence regarding tumour-intrinsic genomic biomarkers associated with response to neoadjuvant therapy, encompassing somatic mutations, germline polymorphisms, gene expression profiles, mismatch repair (MMR) status, protein expression, epigenetic markers, and circulating tumour-derived biomarkers across conventional chemoradiotherapy (CRT) and TNT paradigms. Across the reviewed literature, individual somatic mutations, including KRAS, TP53, and BRAF, demonstrated limited reproducibility as predictive biomarkers, although KRAS mutations were recurrently associated with lower pathological complete response (pCR) rates in CRT-era cohorts. Germline polymorphisms in DNA repair (XRCC1) and folate metabolism (MTHFR) genes showed inconsistent associations with treatment response. In contrast, transcriptomic biomarkers demonstrated greater biological coherence, with proliferative, epithelial-mesenchymal transition, and metabolic signatures frequently associated with treatment resistance, while multi-gene classifiers generally outperformed single-gene markers. Among currently available tumour-intrinsic biomarkers, MMR deficiency was the most consistently reported biomarker associated with reduced response to fluoropyrimidine-based regimens, including TNT, although TNT-specific evidence remains comparatively limited. Dynamic circulating tumour DNA (ctDNA) monitoring, particularly ctDNA clearance during or after therapy, was consistently associated with pathological response and long-term oncologic outcomes across reviewed studies, whereas baseline ctDNA levels showed limited predictive value. Overall, the reviewed literature suggests that biomarker research in rectal cancer has evolved from single-gene analyses towards pathway-level and dynamic biomarkers. The integration of transcriptomic signatures, MMR status, and dynamic ctDNA monitoring may represent a promising strategy for personalising neoadjuvant therapy, improving patient selection for organ-preserving approaches, and enhancing oncologic outcomes in locally advanced rectal cancer. Nevertheless, the evidence base remains heterogeneous, and further prospective validation, assay standardisation, and evaluation within contemporary TNT cohorts are required before these biomarkers can be routinely incorporated into clinical decision-making.

Humans↗

HIF-1 signaling contributes to lenvatinib resistance in patient-derived HCC organoids.

Resistance to lenvatinib remains an important limitation in hepatocellular carcinoma treatment. Six patient-derived organoid lines were established and classified as sensitive or resistant according to ex vivo drug responses, retaining histological and immunophenotypic features of matched parental tumors. Resistant organoids showed unchanged ATP activity, whereas sensitive ones exhibited pronounced morphological changes and reduced ATP activity at higher concentrations. Transcriptome sequencing identified 408 upregulated and 269 downregulated genes in resistant versus sensitive organoids, with HIF-1 signaling among altered pathways. In resistant organoids, lenvatinib increased HIF-1α, ANGPT2, and HK3 mRNA, whereas comparable changes were not detected in sensitive organoids. KC7F2 reduced these transcripts and further decreased ATP activity when combined with lenvatinib. In organoid-derived xenografts, this combination suppressed tumor growth and HIF-1 target expression more than lenvatinib alone, indicating HIF-1 signaling contributes to the resistant phenotype and its inhibition may enhance response.

Drug resistance↗