Targeting immune checkpoints, specifically programmed death 1, has significantly improved clinical outcomes in non-small cell lung cancer. However, only a proportion of patients benefited from immune checkpoint blockades (ICBs) therapy. Thus, identifying novel biomarkers to better select responders to ICBs is critically important in clinical practice. This retrospective study included two cohorts, a discovery cohort (n = 24) and a validation cohort (n = 21) of lung adenocarcinoma (LUAD) patients treated with ICB at Shanghai Pulmonary Hospital between April 2016 and November 2019. Formalin-fixed paraffin-embedded tissue samples were collected for RNA sequencing. Additionally, a TCGA dataset (GSE135222) and a clinical study dataset (POPLAR) were utilized as external validation and test sets, respectively. In the discovery cohort, cilia-associated pathways were significantly enriched in LUAD patients with non-durable benefit. A three-gene cilia-associated signature (TMEM100, DNAH3, and NEFH) was established and effectively predicted resistance to ICB treatment (discovery cohort, Hazard Ratio [HR, 95

Background With the increasing progression of bevacizumab and the urgent need for anti-angiogenic strategies, we aimed to evaluate the efficacy and safety of anlotinib in bevacizumab-pretreated patients with non-squamous non-small cell lung cancer. Methods This was a retrospective real-world study. We enrolled bevacizumab-naïve patients and bevacizumab-pretreated patients from six hospitals during Jan 2018 and May 2024. Progression-free survival (PFS) was the primary outcome. Secondary outcomes included objective response rate (ORR), disease control rate (DCR) and safe outcome. Results A total of 1256 patients were screened, and 746 patients were included in the study. Firstly, we selected patients treated with anlotinib monotherapy. After propensity score matching (PSM), we divided them into beva-pretreated (n = 73) and beva-naïve group (n = 146), and no statistical differences were observed in PFS (6.43 vs. 7.60 months; HR 1.14, p = 0.334). So previous bevacizumab didn't affect the efficiency of anlotinib in non-squamous NSCLC. We further divided the bevacizumab-pretreated patients into three groups according to the post-treatment: anlotinib monotherapy (n = 108), anlotinib combination (n = 345), and other therapies (n = 119). After PSM, the PFS was similar between the anlotinib monotherapy (n = 93) and other treatment group (n = 93) (5.90 vs. 5.23 months; HR 0.96, p = 0.766), whereas the PFS was significantly longer in the anlotinib combination group (n = 297) than other treatment group (n = 99) (6.50 vs 5.23 months; HR 0.82, p = 0.048). Conclusion This study demonstrated that previous bevacizumab didn't affect the efficiency of anlotinib in non-squamous NSCLC. For beva-pretreated patients, combined with anlotinib was effective and well-tolerated. Further studies are warranted to confirm these results and explore the potential advantages of anlotinib.

Purpose Uncommon epidermal growth factor receptor (EGFR) mutations account for ∼10% of EGFR-altered non-small cell lung cancer (NSCLC) and show heterogeneous sensitivity to EGFR-tyrosine kinase inhibitors (TKIs), with limited prospective evidence to inform first-line therapy. Sutetinib is an irreversible EGFR-TKI. We assessed the safety and antitumor efficacy of sutetinib in patients with locally advanced or metastatic NSCLC with uncommon EGFR mutations. Methods In this multicenter, open-label, single-arm phase IIb trial, adults with locally advanced or metastatic NSCLC harboring EGFR G719X, S768I, L861Q, or predefined compound mutations and no prior EGFR-TKI therapy were enrolled. Patients received sutetinib 80 mg orally once daily in 28-day cycles until radiographic progression or unacceptable toxicity. Patients who received at least one dose of treatment and evaluable for efficacy analysis were included in the primary analysis, and all patients who received at least one dose of treatment were included in the safety analysis. The primary endpoint was objective response rate (ORR), as assessed by the independent review committee (IRC). Secondary endpoints included duration of response (DoR), disease control rate (DCR), time to response (TTR), progression-free survival (PFS), overall survival (OS), and safety. Results From December 9, 2021, to May 5, 2024, 99 patients were enrolled (efficacy-evaluable, n=96; safety, n=99). As of data cut-off in October, 2024, the median follow-up was 16.6 months. The IRC-confirmed ORR was 70.8% (95% confidence interval [CI], 60.7-79.7) and the DCR was 90.6% (95% CI, 82.9-95.6). Median DoR was 12.0 months (95% CI, 9.3-15.7) and median PFS was 13.7 months (95% CI, 10.9-16.4). Median OS was not reached (95% CI, 22.2-not reached). ORR was numerically higher in patients with compound versus solitary uncommon EGFR mutations (84.4% vs 64.1%), with median PFS of 13.8 versus 11.0 months, respectively. Treatment-related adverse events (TRAEs) of any grade occurred in 97.0% (96/99) of patients, and grade ≥3 TRAEs occurred in 42.4% (42/99). The most common grade ≥3 TRAEs were diarrhea (28.3% [28/99]), hypokalemia (8.1% [8/99]), and increased gamma-glutamyl transferase (5.1% [5/99]). TRAEs led to dose reduction in 34.3% (34/99) and treatment discontinuation in 4.0% (4/99). No treatment-related deaths occurred. Conclusions Sutetinib met the prespecified primary endpoint and demonstrated clinically meaningful antitumor activity with a manageable safety profile in advanced NSCLC harboring uncommon EGFR mutations (G719X, S768I, and L861Q). These findings support sutetinib as a potential treatment option for this molecularly heterogeneous population. Trial registration NCT 05168566

BACKGROUND:As an extremely rare independent pathological subtype of lung adenocarcinoma, PEAC exhibits potentially distinct clinicopathological, radiological, and molecular characteristics. Currently, there were no large-sample studies reporting its features. METHODS:Patients with PEAC who underwent surgical resection from March 2013 to December 2023 were included in the study. The clinicopathological, imaging features, radiological subtypes and recurrence patterns were analyzed. Recurrence-free survival (RFS) and overall survival (OS) were assessed by Kaplan-Meier curves and compared between groups using log-rank tests. Cox proportional hazards models were used to assess associations with outcomes. RESULTS:The final study population consisted of 81 patients (mean age, 63 years; age range, 36-79 years) including 60 men and 21 women. Radiologically, lesion subtypes were categorized as part-solid (6.2 %, 5/81), pure-solid (90.1 %, 73/81), and pneumonic-type PEAC (3.7 %, 3/81). Pneumonic-type PEACs were more prevalent in higher clinical T stages, whereas all part-solid PEACs were confined to the T1 stage (P = .001). In the part-solid subtype group, both RFS and OS rate were significantly higher than those in the pneumonic-type group and the pure-solid group (P = .001 and P = .0095). Tumor-node-metastasis(TNM) stage III emerged as an independent risk factor for recurrence (hazard ratio, 4.699 [95 % confidence interval: 1.967, 11.080]; P < .001). Pathological nodal involvement (hazard ratio, 24.301 [95 % confidence interval: 5.172, 114.195]; P < .001) was as independent predictor of poor OS. Intrapulmonary metastasis was identified as the predominant recurrence pattern in PEAC. CONCLUSION:PEAC had distinct imaging characteristics. Survival outcomes vary significantly across different imaging subtypes, with prognosis largely determined by TNM stage.

8563 Background: Local consolidative therapy (LCT) has been demonstrated to augment the survival benefits of immunotherapy in non-small cell lung cancer (NSCLC) patients with oligo-residual disease (ORD) in the phase2 BOOSTER Trial (ChiCTR2000032479) as previously reported (2024 WCLC OA05.03; Signal Transduction and Targeted Therapy 2025). Here we report updated data with longer follow-up. Methods: This randomized, phase 2 trial enrolled patients with advanced NSCLC who developed oligo-residual disease after anti-PD-1/L1 therapy, defined as partial response or stable disease as the best response with residual tumors confined to a maximum of three organs and five lesions. Participants were randomly assigned (2:1) to receive ablation (thermal ablation or cryoablation) plus immunotherapy or immunotherapy maintenance alone. The primary endpoint was progression-free survival (PFS). The secondary endpoints were overall survival (OS), safety, patterns of disease progression and immunogenic changes after ablation. Results: Among 65 patients enrolled, the full analysis set finally included 42 patients in ablation plus immunotherapy group and 20 patients in immunotherapy maintenance group. In this updated data cutoff (December 2025) compared to the prior data cutoff (March 2024), median duration of follow-up has increased from 17.8 months to 28.9 months. Patients receiving ablation were associated with significantly longer PFS than those without ablation (median 28.1 vs. 12.8 months, p < 0.001, HR = 0.310, 95%CI 0.169–0.596). The median OS was not reached in either group. The 48-months OS rate were 79.0% (95% CI, 59.5–90.0) in ablation group and 67.6% (95% CI, 41.3–84.1) in the without ablation group. Updated subgroup analysis further suggested a trend of superior efficacy of cryoablation (n=13) compared with thermal ablation (n=29), with a median PFS of 37.6 versus 22.4 months, respectively (p=0.028). The safety profile of ablation combining with immunotherapy was similar to previously reported, and most of the adverse events were well managed. Conclusions: With extended follow up, the updated data suggested that the addition of local consolidative ablation confers durable clinical benefit in patients with advanced NSCLC who develop ORD after anti-PD-1/L1 therapy. Cryoablation was associated with potentially superior survival outcomes compared with thermal ablation. Clinical trial information: ChiCTR2000032479.

Our study aims to compare the clinicopathological, genetic, and prognostic differences between pure-solid appearance clinical stage I mucinous and non-mucinous adenocarcinomas. Five hundred seventy-nine patients with radiological pure-solid appearance clinical stage I lung adenocarcinoma, were retrospectively evaluated. Clinicopathological, radiological, genetic characteristics, and recurrence patterns were compared between the non-mucinous adenocarcinoma and mucinous adenocarcinoma groups. Recurrence-free survival (RFS) and overall survival (OS) were assessed by Kaplan–Meier curves and compared between groups using log-rank tests. Cox proportional hazard models were used to analyze prognostic factors. Of 579 patients (mean age, 59.9 years ± 9.7 [SD]; 298 women), 442 had non-mucinous adenocarcinoma, and 137 had mucinous adenocarcinoma. The non-mucinous adenocarcinoma group, in comparison with mucinous adenocarcinoma, showed higher CEA levels (p = 0.003), higher CT values (36.88 vs 20.89 HU, p < 0.001), a higher incidence of emphysema (25.1

BACKGROUND:First-line amivantamab plus carboplatin-pemetrexed demonstrated efficacy and an acceptable safety profile in the PAPILLON trial (NCT04538664) in patients with advanced non-small cell lung cancer with epidermal growth factor receptor (EGFR) exon 20 insertions; we report the efficacy and safety results of the Chinese mainland subgroup population from the PAPILLON study. METHODS:PAPILLON was a randomized, open-label, multicenter, phase 3 study comparing amivantamab plus carboplatin-pemetrexed therapy with standard of care carboplatin-pemetrexed, in patients with treatment-naïve, locally advanced, or metastatic non-small-cell lung cancer characterized by EGFR exon 20 insertion mutations. Between March 2021 and October 2022, 87 treatment-naïve patients were randomized in China (amivantamab plus carboplatin-pemetrexed, 39; carboplatin-pemetrexed, 48). The primary endpoint was progression-free survival as assessed by blinded independent central review according to Response Evaluation Criteria in Solid Tumors v1.1. Comparison between treatment groups was conducted using a stratified log-rank test, with hazard ratios estimated from a stratified Cox proportional hazards model. RESULTS:Progression-free survival was longer in the amivantamab plus carboplatin-pemetrexed group than in the carboplatin-pemetrexed group (median, 12.3 months, 95% confidence interval [CI], 7.0 months to not evaluable vs. 6.7 months, 95% CI, 4.2-8.6 months; hazard ratio, 0.47; 95% CI, 0.26-0.85; nominal P = 0.0109). The 18-month progression-free survival rate was 33% with amivantamab plus carboplatin-pemetrexed and 12% with carboplatin-pemetrexed. The objective response rate was 71.8% (95% CI, 55.1-85.0%) with amivantamab plus carboplatin-pemetrexed and 48.9% (34.1-63.9%) with carboplatin-pemetrexed (odds ratio, 2.46; 95% CI, 1.01-5.98; nominal P = 0.0478). Median progression-free survival after first subsequent therapy was not evaluable for amivantamab plus carboplatin-pemetrexed and 18.8 months for carboplatin-pemetrexed (hazard ratio, 0.32; 95% CI, 0.11-0.88; nominal P = 0.0212). Interim overall survival analysis suggests about 42% improved chance of survival with amivantamab plus carboplatin-pemetrexed vs. carboplatin-pemetrexed. The most common adverse events with amivantamab plus carboplatin-pemetrexed were neutropenia, anemia, leukopenia, and rash. No new safety signals were observed. No patients discontinued amivantamab due to related adverse events. CONCLUSION:Results from the PAPILLON Chinese mainland population were consistent with the overall population and support the use of amivantamab plus carboplatin-pemetrexed in first-line treatment of Chinese patients with EGFR exon 20 insertion-mutated non-small cell lung cancer. TRIAL REGISTRATION:https://clinicaltrials.gov/; registration number, NCT04538664.

Non-small cell lung cancer (NSCLC) accounts for 85% of lung cancer cases, posing a major health burden. Our prior work indicated fibronectin promotes NSCLC angiogenesis and progression by upregulating Wnt-inducible signaling pathway protein 3 (WISP3) and activating Wnt signaling. This study aims to explore WISP3's role and mechanisms in NSCLC progression. Cells were transfected with a reconstructed plasmid to study gene overexpression/silencing effects. Functional assays were conducted, including tube formation, sphere formation, immunohistochemistry, western blotting, Transwell, and MTT. Mass spectrometry and bioinformatics analysis were used to identify differentially expressed proteins and their associated signaling pathways in NSCLC cells. Additionally, the xenograft tumor model of NSCLC was constructed. High expression of WISP3 in NSCLC is associated with poor prognosis, as it enhances angiogenic and tumorigenic potential in NSCLC cells, further verified in our constructed xenograft tumor experiment. In terms of mechanisms, the activation of the TGF-β signaling pathway, indicated by p-smad2/3 activation, is implicated in the progression of NSCLC promoted by WISP3. Additionally, overexpression of WISP3 leads to increased syntenin binding protein (SDCBP) expression in vitro and in vivo, and WISP3 binding to SDCBP enhances angiogenic and tumorigenic potential in NSCLC, which can be counteracted by silencing SDCBP, indicating their crucial role in NSCLC progression. We offer new insights into WISP3's role in promoting NSCLC progression, showing it upregulates SDCBP and is involved in TGF-β signaling. The findings contribute to a better understanding of NSCLC biology and suggest potential therapeutic targets for the disease.

Background:Pulmonary sarcomatoid carcinoma (PSC) represents a rare subtype of non-small cell lung cancer (NSCLC), and it has poor pathologic differentiation, aggressive progression, and early metastasis. Conventional antitumor therapies demonstrate limited efficacy against PSC, which is frequently associated with unfavorable clinical outcomes. Methods:We conducted an open-label, single-arm Phase II trial. This study has been registered with Clinical Trials (ChiCTR2000031478). Patients received immune checkpoint inhibitor (ICI) combination with chemotherapy, the treatment continued until disease progression, unacceptable toxicity, patient withdrawal, or death. The primary endpoint was objective response rate (ORR), with secondary endpoints comprising progression-free survival (PFS), disease control rate (DCR), overall survival (OS), and treatment-emergent adverse events. Results:From March 2021 through August 2023, a total of 38 patients were enrolled. The study comprised predominantly male participants (91%, n=34) with a median age of 65.4 years. Notably, 86.8% (n=33) had smoking histories. The ORR and DCR were 73.7% and 94.7%, respectively. The median PFS was 13.3 months (95% CI, 10.2-15.7) and median OS was not reached. The most common immune-related adverse events were pneumonitis, the incidence of which was 13.2%. The majority of observed AEs were grades 1 or 2 and all AEs were manageable. Only two patients discontinued treatment due to grade 3 immune-related pneumonitis during the study. Conclusion:In our trial, we found that ICI combination with chemotherapy showed robust efficacy alongside acceptable toxicity in advanced-stage PSC. Taken together, ICI combination with chemotherapy could be a better option for PSC.

Local consolidative therapy (LCT) has been demonstrated to enhance the survival benefits of immunotherapy in non-small cell lung cancer (NSCLC) patients with oligometastatic or oligoprogressive disease. This randomized, phase 2 trial investigated the efficacy and safety of ablation combining continuous immunotherapy in NSCLC patients with oligo-residual disease (ORD) after anti-PD-1/L1 therapy (ChiCTR, identifier: ChiCTR2000032479). From March 2021 to March 2024, 65 patients were randomly assigned (2:1) to ablation combination group (n = 43) and immunotherapy maintenance group (n = 22), and the full analysis set finally included 42 patients in ablation plus immunotherapy group and 20 patients in immunotherapy maintenance group. With a median follow-up duration of 17.8 months, patients receiving ablation combination were associated with significantly longer PFS (median 26.7 vs. 11.7 months, p < 0.001, HR = 0.213, 95%CI 0.099–0.461) and a trend of longer OS (p = 0.036, HR = 0.242, 95%CI 0.057–1.019) than those without ablation. Subgroup analysis showed that cryoablation (n = 13) yielded potentially superior survival than thermal ablation (n = 31) (mPFS: NA vs. 22.4 months, p = 0.011), which might induced by the elevated level of IFN-α after cryotherapy compared to thermal ablation (p = 0.078). Additionally, ablation combination group showed a decreased rate of systemic progression pattern compared with immunotherapy maintenance group. Regarding safety, the combination of ablation and immunotherapy was well tolerated, with only 1 patient experiencing grade 3 pneumothorax after ablation. In conclusion, the addition of ablation is well-tolerated and prolongs the survival of immunotherapy in patients with advanced NSCLC who develop ORD after anti-PD-1/L1 therapy, while cryoablation showing potentially superior survival benefit compared to thermal ablation.

INTRODUCTION:The generation of drug-tolerant persister (DTP) cancer cells remains a major challenge in treating lung adenocarcinoma (LUAD) patients with EGFR tyrosine kinase inhibitors (TKIs), as these cells eventually drive drug resistance and disease progression. However, the mechanisms underlying DTP formation are poorly understood, limiting therapeutic options upon the emergence of DTP state or resistance after TKI therapy. METHODS:In this study, we analyzed samples from LUAD patients receiving frontline osimertinib therapy (including baseline, DTP, and stable resistance states) to dissect the cellular and transcriptomic features of TKI-induced DTP cells via single-cell RNA sequencing. Corresponding in vitro/in vivo experiments and external cohort validation were further conducted to validate key findings from clinical sample analysis. RESULTS:DTP cells exhibited an active drug-metabolizing phenotype, characterized by significantly upregulated GSTA1 expression regulated by RSPH1. Mechanistically, elevated GSTA1 expression in cancer cells promoted osimertinib degradation. Additionally, RSPH1+ DTP cells interacted with macrophages via PROS1-AXL signaling to establish an immunosuppressive tumor microenvironment, contributing to persister formation. Investigation of the RSPH1-CALML4-GSTA1 regulatory axis showed PROS1 expression was also governed by this axis, suggesting GSTA1 acts as an upstream regulator of the PROS1-AXL pathway. The feasibility of osimertinib combined with the GSTA1 inhibitor curzerene was evaluated in osimertinib-induced DTP and acquired resistance mouse models. Notably, this strategy showed superior efficacy compared with osimertinib combinations with chemotherapy or AXL inhibitor in both settings. CONCLUSION:Collectively, this study elucidated novel mechanisms underlying TKI-induced DTP state and provided a promising combination strategy for overcoming drug tolerance and resistance in osimertinib-treated LUAD patients.

Endobronchial ultrasound (EBUS) is a widely used imaging modality for evaluating thoracic lymph nodes (LNs), particularly in the staging of lung cancer. Artificial intelligence (AI)-assisted EBUS has emerged as a promising tool to enhance diagnostic accuracy. However, its effectiveness in differentiating benign from malignant thoracic LNs remains uncertain. This meta-analysis aimed to evaluate the diagnostic performance of AI-assisted EBUS compared to the pathological reference standards. A systematic search was conducted across PubMed, Embase, and Web of Science for studies assessing AI-assisted EBUS in differentiating benign and malignant thoracic LNs. The reference standard included pathological confirmation via EBUS-guided transbronchial needle aspiration, surgical resection, or other histological/cytological validation methods. Sensitivity, specificity, diagnostic likelihood ratios, and diagnostic odds ratio (OR) were pooled using a random-effects model. The area under the receiver operating characteristic curve (AUROC) was summarized to evaluate diagnostic accuracy. Subgroup analyses were conducted by study design, lymph node location, and AI model type. Twelve studies with a total of 6,090 thoracic LNs were included. AI-assisted EBUS showed a pooled sensitivity of 0.75 (95

Most small cell lung cancer (SCLC) patients exhibit resistance to immune checkpoint inhibitors (ICIs) and demonstrate downregulation of major histocompatibility complex class I (MHC-I) molecules. This study aimed to elucidate the regulatory mechanisms underlying MHC-I expression and potential combination strategies. Single-cell and bulk RNA sequencing data from SCLC patients were analyzed. Clinical data from SCLC patients treated with PD-1/PD-L1 inhibitors were used to investigate the associations between treatment efficacy and IFITM3 expression. In vitro and in vivo functional studies were conducted to evaluate the role and mechanisms of IFITM3 in modulating tumor sensitivity to PD-1 inhibitors. Integrative analysis of multiple real-world SCLC cohorts confirmed a significant positive association between IFITM3 expression and MHCI. IFITM3 overexpression upregulated MHC-I-related genes, enriched antigen presentation pathways, and increased CD8+ T-cell infiltration and cytotoxicity. Elevated IFITM3 expression was significantly associated with prolonged progression-free survival (PFS) in patients receiving chemoimmunotherapy but not in those treated with chemotherapy alone. Additionally, patients with high H-scores for IFITM3, as determined by immunohistochemistry, demonstrated better clinical outcomes with chemoimmunotherapy. Inducing IFITM3 expression directly or through treatment with ethyl gallate (EG), an IFITM3 inducer, effectively sensitized tumors to PD-1 blockade in SCLC mouse models. Mechanistic studies revealed that IFITM3 upregulates NLRC5, a key transcriptional activator of MHC-I, facilitating its nuclear translocation and thereby increasing MHC-I levels. IFITM3 is associated with MHC-I expression and can predict the efficacy of anti-PD-1/-L1 therapy in SCLC patients. IFITM3 inducers potently improved the efficacy of anti-PD1 monotherapy in SCLC.

Central and peripheral extensive-stage small-cell lung cancer (ES-SCLC) are reported to be two distinct tumor entities, but their responses to the front-line therapies and underlying biological mechanisms remain elusive. In this study, we first compared the outcomes of central and peripheral ES-SCLC receiving front-line chemotherapy or chemo-immunotherapy with a cohort of 265 patients. Then we performed single-cell RNA sequencing (scRNA-seq) on nine treatment-naïve ES-SCLC samples to investigate potential mechanisms underlying the response differences. Under chemotherapy, the peripheral type had a lower objective response rate (44.8% vs. 71.2%, p = 0.008) and shorter progression-free survival (median 3.4 vs. 5.1 months, p = 0.001) than the central type. When comparing chemo-immunotherapy with chemotherapy, the peripheral type showed a greater potential to reduce progression (HR, 0.18 and 0.52, respectively) and death (HR, 0.44 and 0.91 respectively) risks than the central type. Concerning the scRNA-seq data, the peripheral type was associated with chemo-resistant and immune-responsive tumoral and microenvironmental features, including a higher expression level of MYC-Notch-non-neuroendocrine (MYC-Notch-non-NE) axis and a more potent antigen presentation and immune activation status. Our results revealed that central and peripheral ES-SCLC had distinct responses to front-line treatments, potentially due to differential activation statuses of the MYC-Notch-non-NE axis.

Background:BIRC5, also known as survivin, is the smallest but functionally most complex member of the inhibitor of apoptosis protein (IAP) family and plays an important role in tumorigenesis, recurrence, and chemoresistance, this study aimed to investigate its impact on the clinical and tumor microenvironmental features of lung adenocarcinoma (LUAD), together with its prognostic values. Methods:Clinical and transcriptomic data of 535 LUAD samples, 59 normal lung, and 54 patients with non-small cell lung cancer (NSCLC) received immune checkpoint blockades (ICBs) were analyzed. Immune infiltration analysis was conducted to uncover the relationship between tumor microenvironmental features and BIRC5 expression level. The prognostic values of BIRC5 were also evaluated with log-rank test and Cox regression analysis. Results:LUAD had a significantly higher BIRC5 expression level than normal lung tissues. The elevated BIRC5 expression was markedly associated with unfavorable clinical outcomes. Transcriptomic and single-cell sequencing data analysis revealed that tumors with high BIRC5 expression was correlated with multiple pathways' enrichment. Immune infiltration analysis indicated a negative correlation between BIRC5 expression and infiltration levels of CD8+ T cells, dendritic cells (DCs), and natural killer (NK) cell in LUAD, but a positive correlation was observed between BIRC5 expression and regulatory T cells (Tregs) infiltrations. Importantly, NSCLC patients received ICB with high BIRC5 expression had dramatically shorter progression-free survival (PFS; 1.2 vs. 4.5 months; P=0.01) and overall survival (OS; 3.1 vs. 12.7 months; P=0.005) than those with low BIRC5 expression. Conclusions:These findings suggested that high BIRC5 expression was associated with DNA damage/repair, cell invasion and proliferation related pathways enrichment and increased Tregs infiltration, which would result in inferior outcomes in NSCLC received ICB.

8105 Background: Majority of small cell lung cancer (SCLC) patients exhibit resistance to immune checkpoint inhibitors (ICIs), which is associated with the downregulation of major histocompatibility complex class I (MHC-I) molecules. This study investigates the regulatory mechanisms underlying MHC-I expression and explores potential therapeutic strategies to enhance ICI efficacy. Methods: Single-cell and bulk RNA sequencing data from SCLC patient tumors were analyzed to identify key regulators of MHC-I expression. The IMpower133 cohort (116 patients treated with chemotherapy plus anti-PD-L1 therapy and 131 patients treated with chemotherapy alone) and an in-house cohort (39 patients treated with chemotherapy and anti-PD-1 therapy) were utilized to assess the association between IFITM3 expression and immunotherapy outcomes. Additionally, tumor samples from 42 extensive-stage SCLC patients receiving first-line chemotherapy plus anti-PD1/PD-L1 were evaluated via immunohistochemistry (IHC) to determine IFITM3 expression as a predictive biomarker. In vitro and in vivo functional studies were conducted to elucidate the role and mechanisms of IFITM3 in modulating tumor sensitivity to PD-1 inhibitors. Results: Integrative analysis of multiple real-world cohorts of SCLC confirmed a significant positive association between IFITM3 and MHC-I expression. IFITM3 overexpression elevated MHC-I-related genes, activated antigen presentation pathways, and enhanced CD8 + T cell activity. In the IMpower133 cohort, high IFITM3 expression was significantly associated with prolonged progression-free survival (PFS) in patients receiving chemoimmunotherapy (HR 0.65,95% CI 0.44-0.96, p=0.014) but not in those treated with chemotherapy alone (HR 1.97,95%CI 1.19-3.25, p=0.0069). Similarly, in the in-house cohort, high IFITM3 expression conferred a PFS advantage in patients receiving chemoimmunotherapy (HR 0.42,95% CI 0.19-0.90, p=0.023). Furthermore, patients with elevated IFITM3 protein levels, as determined by IHC H-scores, exhibited improved clinical outcomes following chemoimmunotherapy. Importantly, inducing IFITM3 expression directly or through treatment with Ethyl gallate (EG), an IFITM3 activator, effectively sensitized tumors to PD-1 blockade in SCLC mouse models. Conclusions: IFITM3 positively regulates MHC-I expression and predicts response to ICIs in SCLC. Combining EG with PD-1 inhibitors represents a promising strategy to improve immunotherapy efficacy in SCLC patients.

Background: Recurrent malignant pleural effusion (MPE) resulting from non-small-cell lung cancer (NSCLC) is easily refractory to conventional therapeutics and lacks predictive markers. The cellular or genetic signatures of recurrent MPE still remain largely uncertain. Methods: 16 NSCLC patients with pleural effusions were recruited, followed by corresponding treatments based on primary tumours. Non-recurrent or recurrent MPE was determined after 3-6 weeks of treatments. The status of MPE was verified by computer tomography (CT) and cytopathology, and the baseline pleural fluids were collected for single-cell RNA sequencing (scRNA-seq). Samples were then integrated and profiled. Cellular communications and trajectories were inferred by bioinformatic algorithms. Comparative analysis was conducted and the results were further validated by quantitative polymerase chain reaction (qPCR) in a larger MPE cohort from the authors' centre (n = 64). Results: The scRNA-seq revealed that 33 590 cells were annotated as 7 major cell types and further characterized into 14 cell clusters precisely. The cell cluster C1, classified as Epithelial Cell Adhesion Molecule (EpCAM)+ metastatic cancer cell and correlated with activation of tight junction and adherence junction, was significantly enriched in the recurrent MPE group, in which Claudin-4 (CLDN4) was identified. The subset cell cluster C3 of C1, which was enriched in recurrent MPE and demonstrated a phenotype of ameboidal-type cell migration, also showed a markedly higher expression of CLDN4. Meanwhile, the expression of CLDN4 was positively correlated with E74 Like ETS Transcription Factor 3 (ELF3), EpCAM and Tumour Associated Calcium Signal Transducer 2 (TACSTD2), independent of driver-gene status. CLDN4 was also found to be associated with the expression of Hypoxia Inducible Factor 1 Subunit Alpha (HIF1A) and Vascular Endothelial Growth Factor A (VEGFA), and the cell cluster C1 was the major mediator in cellular communication of VEGFA signalling. In the extensive MPE cohort, a notably increased expression of CLDN4 in cells from pleural effusion among patients diagnosed with recurrent MPE was observed, compared with the non-recurrent group, which was also associated with a trend towards worse overall survival (OS). Conclusions: CLDN4 could be considered as a predictive marker of recurrent MPE among patients with advanced NSCLC. Further validation for its clinical value in cohorts with larger sample size and in-depth mechanism studies on its biological function are warranted. Trial registrationNot applicable.