Molecular Oncology

Diffuse Large B-cell lymphoma (DLBCL) is the most common aggressive lymphoma in the Western world. First-line immunochemotherapy fails in approximately 30-40% of patients, with refractory and relapse patients presenting a dismal prognosis. Currently, these high-risk patients cannot be accurately identified at diagnosis. Using statistical modeling and machine learning approaches applied to large public DLBCL datasets, we identified a novel predictive signature based on the reactivation of eight normally silent tissue-dependent genes associated with survival. We then developed a multiplex RT-MLPseq based assay, compatible with formalin-fixed paraffin-embedded (FFPE) samples and transferable into routine clinical practice, enabling analysis of expression of these eight genes and validated their prognosis impact in an independent real-life cohort. This signature could be integrated with current prognostic indices and molecular classifications to improve patient stratification and guide treatment selection toward a personalized theragnostic approach, thereby enhancing management of non-responder patients. Data Sharing StatementFor access to original data, please contact: anouk.emadali@univ-grenoble-alpes.fr Key points- Ectopic activation of 8 tissue-specific genes defines a robust prognostic signature for survival stratification in DLBCL patients - A FFPE-compatible RT-MLPseq assay enables clinical use and improves risk stratification beyond IPI and COO, especially in high-risk patients

BackgroundTriple-negative breast cancer (TNBC) is a clinically aggressive breast cancer subtype. It is a heterogeneous disease that remains difficult to stratify and that still lacks durable and biomarker-guided therapeutic options. Low expression of the tumour suppressor MTUS1 is associated with aggressive breast cancer features, but the biological properties of MTUS1-low TNBC remain insufficiently defined. Our goal was to determine whether low MTUS1 expression defines shared proliferative and stress-adaptation mechanisms that could guide candidate therapeutic strategies and corresponding target/drug pairs in MTUS1-low TNBC. MethodsWe labelled tumours from seven public TNBC RNA-seq cohorts based on the lowest and highest MTUS1 expression tertiles. Differential gene expression was analysed using gene set enrichment analysis (GSEA) on the Hallmark pathway database to identify deregulated biological pathways between MTUS1-low TNBC tumours and their MTUS1-high counterparts. Reproducibility was examined across independent TNBC cohorts and secondarily in broader breast cancer and selected TCGA tumour cohorts. Gene essentiality scores from CRISPR-Cas9 experiments in TNBC cell-line models were correlated to MTUS1 expression in these cell lines, to propose therapeutic strategies and their corresponding candidate target/drug pairs. ResultsMTUS1-low tumours showed a reproducible pathway-level proliferation mechanism driven by the MYC oncogene and sustained by up-regulated oxidative phosphorylation, combined with stress adaptation mechanisms involving unfolded protein response (UPR), and DNA repair Hallmark gene sets. Based on CRISPR data, we propose 3 therapeutic strategies: (1) targeting MYC to reduce its transcriptional activity, (2) targeting proteins from UPR, (3) targeting DNA-repair. We also propose corresponding candidate target/drug pairs to allow experimental validation of these strategies. ConclusionsProliferation in low MTUS1 TNBC is driven by MYC and stress-adaptation mechanisms. By linking this tumour profile to CRISPR-derived dependency signals, our analysis prioritises experimentally testable target-pathway hypotheses centred on MYC, UPR/proteostasis, and DNA-repair or checkpoint control. Although the proposed therapeutic strategies and candidate targets remain to be experimentally tested, the latter finding is consistent with published work showing that ATIP3-deficient TNBC cell line models are sensitive to inhibition of the WEE1 PKMYT1 G2/M checkpoint kinases.

BackgroundBreast cancer exhibits extensive molecular heterogeneity across intrinsic subtypes, yet convergent metabolic reprogramming may represent an obligate feature of tumour initiation. We hypothesised that suppression of nuclear-encoded mitochondrial fatty acid oxidation (FAO) constitutes such a convergence point, defining a shared metabolic phenotype independent of subtype. MethodsRNA-seq data from 1,106 primary breast tumours and 113 normal-adjacent tissues (TCGA-BRCA) were intersected with 1,079 nuclear-encoded mitochondrial genes from MitoCarta 3.0. Differential expression was assessed using Welch t-test with Benjamini-Hochberg correction at all tumour stages, at Stage I specifically, and stratified across PAM50 subtypes. A 55-gene core FAO signature was derived by three-way intersection. Ten candidate genes were selected by pre-specified objective scoring, locked before any clinical testing. Gene set enrichment analysis (GSEA) was performed using MitoCarta 3.0 pathway annotations. Diagnostic performance, clinical associations, survival, and mutation independence were characterised. External validation used two independent GEO cohorts (GSE42568, n = 121; GSE109169, n = 50); prognostic validation used METABRIC (Molecular Taxonomy of Breast Cancer International Consortium; n = 1,980). DESeq2 was applied as methodological cross-validation. ResultsAmong 126 differentially expressed mitochondrial genes, fatty acid oxidation was the most significantly depleted pathway (normalised enrichment score -2.130; false discovery rate 0.001). The 55-gene core signature replicated in both external cohorts with 100% directional concordance (hypergeometric p < 10-{superscript 1}). All 10 candidate genes discriminated tumour from normal tissue (area under the curve 0.915-0.979) and demonstrated broad clinical associations. The composite FAO suppression score predicted overall survival in METABRIC (log-rank p = 7.82 x 10-) and MAOA achieved independent prognostic significance in multivariable Cox regression (hazard ratio 0.890; adjusted p = 0.009). DESeq2 cross-validation confirmed Spearman {rho} = 0.980 concordance. ConclusionsNuclear-encoded FAO suppression is a robust, pan-subtype feature of breast cancer detectable at Stage I and validated across independent platforms and cohorts. These 10 candidate genes constitute a consistent initiation-phase mitochondrial signature, implicating FAO suppression as a potential convergence point in breast cancer oncogenesis and motivating targeted functional investigation.

BackgroundRecent evidence suggests that cancer can exhibit splicing alterations that give rise to tumour-specific isoforms. One example is NUMB, which produces four isoforms (p72, p71, p66, and p65) through alternative splicing of exons 3 and 9. Traditionally considered a tumour suppressor, it also has been considered an oncogene. We propose that this duality is due to isoform-specific expression. ResultsUsing public databases, we identified a tumour-associated switch in NUMB isoform expression: p72/p71 are upregulated in tumours, whereas p66/p65 are more expressed in non-tumour tissues. These isoforms correlate differently with cellular processes. NUMBL, a NUMB homolog, behaves similarly to p65. We identified two transcriptional clusters: one characterized by high expression of p72/p71, and another by p66/p65/NUMBL. Each group was associated differently with the Notch, WNT/{beta}-catenin, Hedgehog, and Hippo signalling pathways, suggesting isoform-specific regulatory roles. Analysis of breast cancer cell lines (CCLE) led to a NUMB score based on isoform expression, which classified cell lines into biologically distinct groups. The p72/p71-enriched group showed distinct signatures, pathway activity, and drug sensitivity. Applying this score to TCGA-BRCA samples revealed a significant link between high NUMB-score and poor survival, confirmed by Kaplan-Meier analysis. ConclusionsNUMB emerges as a potential oncogenic contributor and biomarker in splicing-based personalised medicine, highlighting isoform-specific expression as a clinically relevant determinant of tumour behaviour, pathway activity, and therapeutic response.

Background: Pancreatic ductal adenocarcinoma (PDAC) is characterized by extensive molecular complexity, profound stromal remodeling, and limited responsiveness to systemic therapies. Although gemcitabine-based regimens remain widely utilized, the molecular pathways that influence treatment-associated biological variation are incompletely understood. The TGF{beta} and JAK/STAT signaling networks are recognized regulators of tumor progression, immune modulation, and therapeutic resistance; however, their genomic architecture in clinically stratified PDAC populations remains poorly defined. Methods: We employed a conversational artificial intelligence-driven analytical framework to investigate TGF{beta} and JAK/STAT pathway alterations in a cohort of 184 PDAC patients. Clinical and molecular data were integrated to generate age- and treatment-stratified cohorts, enabling pathway-level and gene-level analyses according to gemcitabine exposure. Findings generated through AI-assisted interrogation were subsequently evaluated using conventional statistical approaches. Results: TGF{beta} pathway alterations were identified in approximately one-quarter to one-third of tumors across clinical subgroups and demonstrated relatively stable frequencies regardless of age at diagnosis or gemcitabine treatment status. Gene-level analyses revealed that pathway disruption was predominantly driven by recurrent alterations in SMAD4, with additional low-frequency events involving TGFBR1 and TGFBR2. Notably, TGFBR2 mutations were significantly more frequent among late-onset PDAC patients receiving gemcitabine compared with untreated late-onset patients (8.8% vs. 1.4%; p = 0.04), suggesting a potential treatment-associated enrichment. In contrast, JAK/STAT pathway alterations were rare throughout the cohort, with only isolated mutations observed in pathway components including JAK1, JAK2, JAK3, STAT1, STAT3, and related regulatory genes. No significant differences in JAK/STAT alteration frequencies were identified according to age or treatment exposure. Conclusions: TGF{beta} and JAK/STAT pathways exhibit distinct genomic architectures in PDAC. TGF{beta} pathway disruption represents a recurrent feature of disease biology, largely driven by SMAD4 alterations, while TGFBR2 enrichment in gemcitabine-treated late-onset tumors suggests a potential context-specific association worthy of further investigation. Conversely, genomic alterations within the JAK/STAT pathway are uncommon, indicating that pathway activity may be regulated predominantly through non-genomic mechanisms. These findings demonstrate the utility of conversational artificial intelligence agents for rapid, scalable, and clinically contextualized pathway interrogation and support future studies integrating multi-omic data to refine precision medicine strategies in PDAC.

Introduction. TAC/SARIFA has been introduced as a new robust and easy-to-evaluate biomarker in several cancer entities, including colorectal cancer. It is defined by direct contact between at least five tumour cells and one adipocyte and is believed to indicate metabolic reprogramming associated with adverse outcome. However, the mechanism that leads to TAC/SARIFA positivity remains unclear. To investigate whether there is an individual component, we conducted a study on double and triple cancers, establishing a within patient design. Methods. We retrospectively analysed a total of 135 cases with 276 colorectal cancers from two academic medical centres. The TAC/SARIFA status was evaluated, as were the basic histopathological factors. The median follow-up time was 120 months. Results. Cases with any TAC/SARIFA positive tumours showed significantly reduced overall survival (62 vs. 88 months; p = 0.011). Analysing the entire cohort, the rates of concordant and discordant cases followed a random distribution. However, restricting the analysis to synchronous pT3/4 cases revealed a significant deviation from a random distribution (p = 0.016). Conclusion. This study reveals significant concordance of TAC/SARIFA status in synchronous locally advanced colorectal double/triple carcinomas, supporting the concept that tumour adipocyte interaction reflects a host related microenvironmental condition linked to metabolic reprogramming rather than a purely tumour intrinsic event.

EMT associated transcription factors (EMTaTF) controls the epithelial-mesenchymal transition (EMT) process, but their detailed expression pattern in cancer is poorly documented at the cellular level. Here, we located two major EMTaTF: Snail and Slug by immunochemistry using validated antibodies in a cohort of 569 invasive breast carcinomas. We screened all tumor molecular types using TMA analysis in addition to full tumor sections, identifying cell types and structures involved in their expression, correlated to morphological, functional, and clinical characteristics. Briefly, Slug was expressed in Luminal A/B and HER2 breast cancer subtypes by almost all cells from the basal layer in normal-looking tubule structures and was very sporadically seen in transformed cells in the in situ or invasive components. In contrast, Slug was visibly expressed in 28% of our triple-negative (TN) tumor samples, significantly expressed by invasive tumor cells. Slug was also strongly expressed in a large subpopulation of stroma fibroblast-like cells in all breast carcinoma subtypes. Conversely, Snail was frequently expressed in transformed cells in all invasive breast carcinomas subtypes, up to 54 and 64% of tumor cells in TN and HER2 tumors respectively. Expression pattern was heterogeneous and included invasive areas and in situ component. Some stroma cells, particularly endothelial cells from the tumor microenvironment were also found to express Snail. Slug and Snail proteins were also detected in metastatic foci, sometimes with an increase in the expression level, particularly for Snail. Unexpectedly, we found a significant positive correlation between cell proliferation and Slug stroma cell expression in luminal A and B subtypes. This link bolstered the relative proximity we uncovered between CK- KI67- Slug+ stoma cells and CK8+ KI67+ Slug- tumor cells in LumB samples. However, survival long-term studies failed to demonstrate a link between slug tumor or stromal expression and long-term survival. On the other hand, Snail protein expression in tumor cells was surprisingly and significantly linked to a better survival fate overall. In contrast, Snail overexpression in stroma cells from primary tumors was significantly linked to a time-dependent tendency for relapses, metastasis and poorer survival, arising when post-surgery time lapse increased. In conclusion, these findings offer new and unsuspected understanding of the complex localization pattern and clinical involvement of Snail genes in breast cancer, beyond classic EMT pathways.

Integrated prognostic signatures combining ferroptosis, cuproptosis, and disulfidptosis are increasingly reported in oncology as advances in risk stratification, yet their added value over simpler pathway-specific or proliferation-related models remains unclear. Here, we developed an integrated regulated cell-death signature and evaluated it through an adversarial pan-cancer benchmark. Using the TCGA pan-cancer cohort comprising 9,808 tumours across 33 cancer types, we curated 118 genes associated with the three cell-death programmes, characterised inter-pathway crosstalk, and derived a 26-gene LASSO-Cox risk signature. The model showed reproducible prognostic performance across cancers, with a pan-cancer concordance index of 0.573 (95% CI, 0.552-0.594), and was independently validated in METABRIC and CGGA cohorts, remaining significant after adjustment for standard clinical variables. However, benchmarking revealed that the integrated signature, although superior to size-matched random gene sets (empirical p < 0.001), did not outperform a ferroptosis-only model (DeLong p = 0.81), indicating no measurable gain from pathway integration. Moreover, much of the prognostic signal reflected tumour proliferation rather than regulated cell death. After adjustment for the proliferation meta-signature (meta-PCNA), ferroptosis performance declined from 0.573 to 0.504, while the integrated model decreased to 0.554. High-risk tumours were more sensitive to anti-proliferative drugs, and the risk score was most strongly associated with E2F, MYC, and G2M target programmes. The signature stratified prognosis but did not predict immune-checkpoint blockade response in IMvigor210 (AUC {approx} 0.50). Importantly, the underlying biology was not merely a modelling artefact. Signature genes showed concordance with protein abundance in CPTAC cohorts, and the three cell-death programmes co-varied within individual malignant cells, with correlations ranging from {rho} = 0.46 to 0.66. Overall, our findings indicate that integrated multi-death signatures are reproducible and biologically grounded, yet prognostically redundant and substantially confounded by proliferation. This study provides a cautionary benchmark for the rapidly expanding use of composite regulated cell-death signatures in cancer prognosis.

Long non-coding RNAs (lncRNAs) have attracted increasing interest because of their roles as modulators of tumor progression, acting either as oncogenic drivers or tumor suppressors, depending on the cellular context. LINC01133 has been implicated in regulation of multiple tumor-related mechanisms; however, its role in breast cancer, particularly in the triple-negative subtype, remains poorly characterized. In this study, we investigated the impact of LINC01133 depletion on malignant phenotypes and on the expression of migration- and invasion-associated genes using the Hs578T triple-negative breast cancer (TNBC) cell line, through comparative analyses of parental, control, and LINC01133-knockout cell lines, namely Hs578T_wt, Hs578T_ctr, and Hs578T_ko. Functional characterization included morphological analysis, growth assays, anchorage-independent colony formation, migration, invasion, and quantitative biomolecular experiments. Depletion of LINC01133 led to reduction of cell diameter, a significant increase in colony-forming capacity, and marked enhancement of migratory and invasive potential. At the molecular level, LINC01133 loss induced the expression of genes associated with extracellular matrix remodeling and cellular plasticity, including fibronectin, vimentin, integrins, FOXC1, and TWIST1, concomitant with reduced expression of ZEB1, TWIST2, and N-cadherin. Collectively, these data indicate that LINC01133 acts as a potential fine regulator of in vitro migration and invasion processes in TNBC, with its expression favoring a more asymptomatic mode of tumor progression, whereas its loss markedly enhances tumor malignancy.

Background: The use of immune checkpoint inhibitors (ICIs) in the treatment of cancer has rapidly expanded over the last decade. However, there are several knowledge gaps in understanding how tumor cells evade the immune system. There is paucity of data in HPV negative oral cancer, particularly of the gingivobuccal region. Understanding the mechanism of immune system evasion in this cancer is vital for improving patient outcomes. Methods: We characterized the baseline immune milieu of oral cancer using immunohistochemistry (IHC) on whole tumor sections from 124 cases. Tumors were classified as hot or cold and further stratified into high-risk and low-risk groups. High-risk patients included those with lymph node metastasis at diagnosis/recurrence or distant metastasis within 2 years of treatment completion. Patients without these features were categorized as low risk. Validation by RNA-Seq and Joint Enrichment Analysis of Oncogenic and Immunologic Pathways was carried out in a subset of 46 cases. Results: Hot high-risk tumors (by IHC) were distinguished by elevated PD-L1 expression and reduced NK-cell, PD1, and CTLA-4 expression. There was no difference in the expression levels of CD3+, CD8+, granzyme, or perforin compared to hot low-risk tumors, findings that align with the definition of hot tumors. RNA-Seq revealed a gene signature associated with exhausted T-cells in hot high-risk tumors. Gene and pathway analyses identified differential upregulation of isoform-specific TOX, TCF, CXCR, RUNX, IRF, BRD and BCL6 genes, implicating immune cell exhaustion and tumor aggressiveness. Significantly downregulated genes included PDCD1, HAVCR2, ZAP70, and STAT, indicative of a disabled immune microenvironment. These findings support that a state of immune exhaustion in HHR tumors is driven by progenitor exhausted T-cells and terminally exhausted T-cells; independent of PD1-TIM3. Conclusion: These findings suggest that combining TOX/TCF/BCL6 inhibitors with immune checkpoint inhibitors in the adjuvant setting might benefit patients with hot high-risk tumors. Given the results, testing for a targeted exhaustion-related gene panel at diagnosis is recommended for oral cancers to stratify tumors as high-risk or low-risk. Larger validation studies and clinical trials are now warranted.

Faithful proliferation requires coordinated DNA replication with centrosome maturation and spindle-pole integrity. SLD5, encoded by GINS4, is a core component of the GINS replication complex and is frequently elevated in tumors, but whether it links replication-associated cancer states to centrosome control has remained unclear. Here, we show that GINS4/SLD5 is recurrently upregulated across human cancers at transcript and protein levels and marks tumor programs enriched for DNA replication, chromosome segregation, and mitotic control. In cancer cells, Sld5 depletion dispersed PCM1, AZI1, and CEP290-positive centriolar satellites without eliminating these satellite proteins, reduced dynein heavy chain expression, and destabilized dynein-dynactin localization at spindle poles. Direct depletion of dynein heavy chain, co-depletion analyses, and pharmacological inhibition of dynein motor activity with ciliobrevin D phenocopied Sld5 loss, causing satellite dispersion, defective recruitment of PLK1, Aurora A, CEP192, and CEP215 to centrosomes, and multipolar spindle formation. These defects occurred without detectable DNA damage or checkpoint activation, indicating a non-canonical Sld5 function beyond its role in the replisome. Cancer dependency and kinase network analyses further nominate SLD5-associated mitotic and checkpoint pathways as therapeutic targets. Our findings identify SLD5/GINS4 as a regulator of dynein-dependent centrosome maturation and a candidate vulnerability in replication-driven cancers, with potential value for biomarker-guided therapeutic stratification. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/723511v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@e845d8org.highwire.dtl.DTLVardef@141719aorg.highwire.dtl.DTLVardef@1895e1corg.highwire.dtl.DTLVardef@181aa16_HPS_FORMAT_FIGEXP M_FIG C_FIG

Despite continuous progress in diagnosis and therapy, breast carcinoma (BC) remains a major health problem. Triple-negative (Estrogen Receptor-/Progesterone Receptor-/HER2-) breast cancer (TNBC) is the most aggressive subtype due to its high metastatic potential and resistance to chemotherapy. The Y-box binding protein 1 (YB-1) transcription factor, a protein present in both cytoplasm and nucleus, is a driver of TNBC malignancy as it stimulates its cancer stem cell phenotype and disrupts cell cycle progression. Here, we hypothesized that YB-1-containing sEVs deliver YB-1 to the nuclear compartment of recipient cancer cells and play a major role in the activation of the metastatic process. We found a selective enrichment of YB-1 in sEVs from MDA and 4T1 cells, with [~]65% and 50% of all sEVs positive for YB-1 by d-STORM. Administration of sEVs from wild-type MDA and 4T1 to their YB-1 knockout counterparts resulted in nuclear translocation of sEV-associated YB-1 and increased tumorsphere formation. Pharmacological blockade of the nuclear transport machinery based on the inhibition of the formation of the "VOR" complex (VAP-A-ORP3-Rab7) by PRR851 impaired both nuclear translocation and the YB-1-induced increase in tumorsphere formation. YB-1 phosphorylation at S102 was required for nuclear localization. In fact, loss of YB-1 phosphorylation inhibited tumorsphere growth and stemness of cancer cells and YB-1-positive sEVs restored the oncogenic behavior of cancer cells expressing phospho-mutant YB-1. Moreover, PRR851 inhibited the nuclear translocation of the phosphorylated form of YB-1 and the oncogenic behavior of the TNBC cells. These data support the conclusion that the nuclear translocation of sEV-associated phosphorylated YB-1 is an important factor in the malignant behavior of TNBC and a potential therapeutic target.

Aims: Serrated lesions contribute substantially to colorectal cancer (CRC), while routine management of small distal hyperplastic polyps (HPs) assumes low risk. Surveillance guidelines nevertheless incorporate uncertainty at the HP/SSL interface and recommend shortened intervals for large serrated lesions. We tested whether fibroblast activation protein-alpha; (FAPalpha) expression by stromal fibroblasts within expert-reviewed HPs stratifies risk of subsequent neoplasia. Methods and results: In a single centre historical cohort, FAPalpha; immunohistochemistry (Abcam ab53066, 1:200) was performed on FFPE colon tissues from 64 patients (normal colon n=10; HP n=39; low grade TA n=6; high-grade TA n=4; adenocarcinoma n=5). FAPalpha positive stromal fibroblasts were quantified in 20 randomly selected fields at magnification 1000 by two blinded readers (ICC 0.93). Among 39 patients with expert reviewed index HPs and colonoscopic follow up, the endpoint was metachronous adenoma occurring in the same general colonic area as the index HP, with proximal defined as ascending colon and distal as descending colon. Follow-up colonoscopies were scheduled every 2 years for up to 10 years. ROC analysis identified an optimal threshold of [&ge;]9 FAPalpha positive fibroblasts (AUC 0.8658; sensitivity 81.25%, specificity 87.93%). FAPalpha high status (44% of HPs) was associated with shortened neoplasm free survival (log-rank p=0.0012): five-year neoplasm free survival 41% versus 91% for FAPalpha; no/low. In multivariable Cox modelling, FAPalpha high status remained independently associated with metachronous adenoma (HR 4.5, 95% CI 1.2-16.8, p=0.022). Conclusion: FAPalpha+ fibroblasts in expert-reviewed colorectal HPs identify a high-risk subgroup for metachronous adenoma, supporting stromal activation markers as a feasible pathology-anchored stratification tool.

IntroductionMTAP emerges as potential predictive biomarker for MTA-cooperative PRMT5-inhibitors. Although MTAP attracts increasing attention in non-small cell lung cancer, its role in pulmonary neuroendocrine neoplasms (NENs) remains largely unexplored. MethodsHere, we assessed the prevalence of MTAP deficiency in 209 pulmonary NENs using immunohistochemistry (IHC). Additionally, we performed fluorescence in situ hybridization (FISH), whole exome sequencing (WES), deep proteomic profiling, transcriptomic, and methylation analyses of selected MTAP deficient and proficient carcinoids to further elucidate the underlying mechanisms of MTAP expression pattern. ResultsMTAP deficiency by IHC was detected in all neuroendocrine precursor lesions (n=17), 92% of typical carcinoids (n=51), 86% of atypical carcinoids (n=21), and 10% of large cell neuroendocrine carcinomas (LCNEC) (n=30). In contrast, all small cell lung cancers (SCLC) were MTAP proficient (n=90). In MTAP deficient carcinoids, FISH and WES did not detect homozygous 9p21 deletions, and methylation analysis showed no evidence of MTAP promoter hypermethylation. Comparing MTAP deficient and MTAP proficient carcinoids, proteomic data showed a clear separation between the two groups. Further, there was an inverse correlation between the expression of MTAP and OTP (orthopedia homeobox protein), which is known as a strong prognostic marker in pulmonary carcinoids. DiscussionMTAP deficiency is a novel hallmark of neuroendocrine precursors and most pulmonary carcinoids, clearly distinguishing the latter from SCLC and most LCNEC. It is neither caused by 9p21 deletion, nor by MTAP promoter hypermethylation. MTAP deficiency is a group-defining feature of carcinoids that might pave the way for new therapeutic approaches.

Breast cancer is a heterogeneous disease whose clinical management relies heavily on accurate molecular subtyping. The murine E0771 mammary carcinoma cell line is widely used in preclinical studies, yet its molecular identity remains controversial, with reports variably classifying it as luminal B or triple-negative. In this study, we performed an integrated molecular and functional characterization of two independently sourced E0771 cell line stocks to resolve this discrepancy. Both stocks were genetically authenticated and exhibited concordant phenotypes. Immunohistochemical and molecular analyses demonstrated absence of oestrogen and progesterone receptors, classifying E0771 as triple-negative. Functionally, E0771 cells showed no transcriptional response to oestrogen and displayed resistance to endocrine therapy both in vitro and in vivo. Collectively, our results establish E0771 as an oestrogen-independent, basal-like triple-negative breast cancer model, supporting its appropriate use in studies of hormone-resistant breast cancer biology.

Although immune checkpoint inhibitors targeting the programmed death-ligand 1 (PD-L1) axis have transformed the treatment of recurrent and metastatic head and neck squamous cell carcinoma (HNSCC), durable clinical responses remain limited to a minority of patients, and the determinants of treatment resistance remain incompletely understood. Human papillomavirus (HPV) infection, alcohol consumption, tobacco use, and are the three most prominent etiological risk factors for HNSCC; however, despite their well-established individual roles in disease development, the influence of their combined exposure on PD-L1 axis regulation and immunotherapy response remains largely unexplored. In this study, we analyzed multi-omic data from 498 primary HNSCC tumors in The Cancer Genome Atlas (TCGA), stratifying patients into seven subgroups reflecting all observed exposure combinations, with HPV status determined directly from RNA-sequencing reads using Pathoscope. Notably, PD-L1 (CD274) expression was significantly downregulated in the triple-exposure cohort (1.51-fold reduction, p < 0.05), along with reduced expression of the upstream regulator JAK2 (1.44-fold reduction, p < 0.05) being seen. Immune deconvolution suggested progressively greater immune infiltration with accumulating exposures, yet gene set enrichment analysis revealed concurrent downregulation of T cell activation, T cell differentiation, and NK cell-mediated immunity in the triple-exposure subgroup -- consistent with an inflamed but functionally suppressed tumor microenvironment. Preliminary integration with an independent single-cell RNA-sequencing dataset of HNSCC patients undergoing neoadjuvant PD-1/CTLA-4 blockade further suggested enrichment of granulocyte and regulatory T cell populations among non-responding patients. Survival differences between cohorts were also observed, likely reflecting biological heterogeneity driven by distinct etiologies and differences in clinical presentation across exposure groups. Together, these findings provide early insights into how multi-etiological exposure burden may shape PD-L1 axis dysregulation and immune microenvironment remodeling in HNSCC, with potential implications for patient stratification in checkpoint inhibitor therapy.

Squamous cell carcinomas (SCCs) in the lung, head and neck, cervix, and esophagus are characterized by widespread chromosome-arm aneuploidies, most frequently recurrent 3q-gain. However, how these alterations influence cancer development and therapeutic vulnerabilities remains unclear. To identify aneuploidy-driven therapeutic targets, we performed genome-wide CRISPR interference (CRISPRi) and drug-repurposing screens in isogenic immortalized lung epithelial cells harboring chromosome 3-disomy or 3q-gain. Both screens converged on a mevalonate pathway dependency specific to 3q-gain cells, which exhibited heightened sensitivity to sterol regulatory element-binding protein (SREBP) disruption. Rescue experiments demonstrated that these vulnerabilities were on target and that pathway inhibition preferentially causes apoptosis in 3q-gain cells. Transcriptomic and lipidomic profiling revealed 3q-gain-associated alterations in SREBP activation, cholesterol and fatty-acid biosynthesis, and lipid composition. Perturbing SREBP signaling impaired viability in SCC cell lines and suppressed tumor growth in xenografts with 3q-gain. These findings identify an aneuploidy-driven, targetable vulnerability in SCC. SignificanceHere, we demonstrate that SCC-recurrent 3q-gain is a selective vulnerability to SREBP-pathway inhibition. We identify an aneuploidy-driven therapeutic liability in squamous tumors for lipid-targeted precision therapies, providing a framework for targeted treatment in SCC.

Confounding the treatment options available to patients with triple-negative breast cancer (TNBC) are not only its purported lack of hormone receptor and growth factor receptor targets (ER-/ PR-/ HER2-), but its enrichment in plastic and chemoresistant breast cancer stem cells (BCSCs). Although descriptions of non-canonical PR expression in TNBC are rife in the literature, only canonical PR is considered in the definition of TNBC and is used to determine therapeutic strategy, not least because the utility of non-canonical PR modulation in TNBC chemoresistance is largely unexplored and poorly understood. Here we document the expression of three non-canonical PRs and the canonical PR (PGR) phosphorylated at Ser345 (p-PGR S345) in a panel of TNBC and luminal breast cancer cell lines, and employ combined PR agonists and antagonists to investigate the influence of PR activity on TNBC cell viability and PI3K inhibitor cytotoxicity. To examine the contributions of non-canonical membrane-associated PRs mPR{beta} and PGRMC1, we tested the agonist Org OD 02-0, a synthetic progestin targeted to mPRs; the PGRMC1 antagonist Ag-205; and the antagonist SPA70 against the cytosolic/nuclear PXR, in the background of pan-PI3K inhibition with Buparlisib (BUP). We also reveal that combinations of agonists and antagonists targeted to canonical and non-canonical PRs robustly potentiate the cytotoxic effects of PI3K inhibition, and also exhibit significant cytotoxicity on their own. Using functional assays, flow cytometry, immunocytochemistry and protein expression analyses, we found that simultaneously perturbing PRs and inhibiting PI3K function resulted in significantly greater cell death than vehicle control or BUP alone, and reduced the proportion of ALDH1+ BCSCs in two TNBC cell lines. We conclude that four types of PR are tractable targets in TNBC which participate in cell viability and enhance chemotherapy-induced cytotoxicity, and should be re-evaluated in an evolving definition of this challenging disease.

Gastric cancer is driven by aberrant kinase signaling that supports uncontrolled proliferation and metabolic adaptation. Calcium/calmodulin dependent protein kinase kinase 2 (CAMKK2) is overexpressed in gastric cancer; however, its role in regulating metabolic programs that sustain tumor growth remains incompletely understood. In this study, we employed an integrated multi-omics approach with a primary focus on untargeted metabolomics to investigate the consequences of CAMKK2 inhibition in gastric cancer cells. Pharmacological inhibition of CAMKK2 using STO-609 in AGS cells resulted in significant suppression of proliferation, clonogenic growth, migration, and invasion, accompanied by pronounced nuclear abnormalities and multinucleation indicative of mitotic defects. Global metabolomic profiling revealed extensive and time-dependent metabolic reprogramming following CAMKK2 inhibition, characterized by a marked depletion of nucleotide intermediates, including purine and pyrimidine metabolites required for DNA synthesis. Pathway enrichment analysis highlighted suppression of nucleotide metabolism, lipid metabolism, and central carbon metabolic pathways, indicating a broad impairment of biosynthetic capacity. Integration with proteomic and phosphoproteomic datasets demonstrated that metabolic alterations were accompanied by downregulation of DNA replication machinery and attenuation of kinase signaling pathways governing cell cycle progression. Protein metabolite interaction and docking analyses further supported functional coupling between nucleotide metabolites and key replication-associated enzymes, revealing disruption of metabolite enzyme interactions upon CAMKK2 inhibition. Collectively, these findings identify CAMKK2 as a critical regulator of metabolic programs that support DNA replication and cell cycle progression. Its inhibition induces replication stress through coordinated depletion of nucleotide pools and disruption of replication-associated signaling, leading to impaired proliferation and mitotic failure. These results highlight CAMKK2 as a potential therapeutic target for exploiting metabolic vulnerabilities in gastric cancer.

Withdrawal StatementThe authors have withdrawn this manuscript to address issues related to data-use permission and authorship review. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.