Analysis of tissue biopsy samples is the gold-standard approach to cancer diagnosis and patient selection for biomarker-guided therapies. Although spatial analyses of tumour tissue can provide important insights into local antitumour immune responses, repeated tumour biopsy is invasive and rarely feasible for monitoring dynamic immune responses over time. Technical advances have enabled multimodal analyses of cells and cellular products in peripheral blood samples, which can be obtained easily and repeatedly over the course of the disease. These liquid biopsy-based approaches cannot provide spatial information on the tumour immune microenvironment and tumour-derived material can be highly diluted in the circulation, yet they offer a unique opportunity to monitor systemic immune dynamics, anticipate responses to immunotherapies and detect emerging resistance to treatment. Thus, blood-based analyses might complement tumour tissue analysis. In this Review, we discuss insights on systemic antitumour immune responses that can be gained through the analysis of tumour-derived biomarkers in peripheral blood and/or circulating immune cells.

Poor-prognosis cancers account for a disproportionate share of global cancer mortality despite major advances in prevention, early detection, and therapy for other malignancies. Launched in 2023, the G7 Cancer Initiative represents an unprecedented effort to address this challenge through coordinated scientific, clinical, and policy action. This report summarizes the outcomes of the G7 Cancer Conference held in Paris in June 2025, which focused on shifting poor-prognosis cancers from a paradigm of resignation to one of collective transformation. Discussions emphasized four interdependent pillars: precision medicine supported by multi-omic profiling and artificial intelligence; early detection and minimal residual disease monitoring using liquid biopsy and advanced imaging; innovative and adaptive clinical trial designs; and emerging therapeutic platforms, including nanomedicine, epigenetic therapies, and immune modulation. The meeting highlighted that scientific innovation alone is insufficient without harmonized infrastructures, equitable access, and international cooperation. Together, these elements form a new model of global cancer governance aimed at translating biological insight into meaningful survival gains for patients with historically lethal cancers.

PURPOSE Circulating tumor DNA (ctDNA) may serve as a biomarker to facilitate early identification of asymptomatic distant tumor spread in patients with breast cancer. The primary objective of this study was to assess clinical validity and prognostic value of post-treatment tissue-free ctDNA detection by evaluating its sensitivity for distant metastatic recurrence and its association with long-term outcomes. PATIENTS AND METHODS Plasma samples were prospectively collected from patients with stage I-III early breast cancer who participated in the adjuvant SUCCESS-A phase III clinical trial (ClinicalTrials.gov identifier: NCT02181101 ). In this study, plasma samples collected approximately 2 years after completion of adjuvant chemotherapy from 313 SUCCESS A patients without evidence of prior disease recurrence were retrospectively analyzed using a tissue-free epigenomic ctDNA assay (Guardant Reveal). Survival analyses were performed using a landmark approach based on the time of sample collection. RESULTS Overall, ctDNA was detected in 18 of 313 samples (5.8%). Of all ctDNA detected samples, 94% (17/18) were from patients who subsequently developed a distant recurrence, with ctDNA detected at a median interval of 7.9 months before recurrence. ctDNA positivity was strongly associated with a significantly shorter distant recurrence-free interval (hazard ratio [HR], 33.3 [95% CI, 4.12 to 268]; P < .0001) and poorer overall survival (HR, 27.3 [95% CI, 1.15 to 647]; P < .0001). The sensitivity for distant recurrence in patients who had a sample collected within 1 year before recurrence was 73% (11/15). The specificity in nonrecurred patients was 99.6% (267/268). CONCLUSION Tissue-free detection of ctDNA 2 years after adjuvant chemotherapy was highly prognostic in an early-stage breast cancer cohort, and can be used to stratify patients with early-stage breast cancer at high risk for recurrence during follow-up who may benefit from early interventions.

Epithelial-mesenchymal transition (EMT) in breast cancer is better understood as epithelial-mesenchymal plasticity (EMP), a dynamic and reversible spectrum of epithelial, hybrid, and mesenchymal states. In this review, we discuss how EMP is deployed differently across hormone receptor-positive/HER2-negative, HER2-positive, and triple-negative/claudin-low breast cancers, with distinct implications for metastasis, immune evasion, liquid biopsy, and therapeutic resistance. We highlight the regulatory networks and microenvironmental cues that shape state transitions and emphasize that hybrid and plasticity-high states may be more clinically informative than terminal mesenchymal states alone. We propose that progress will depend on subtype-aware, biomarker-guided strategies that resolve carcinoma cell state in space and time and therapeutically exploit EMT-associated vulnerabilities.

Early detection of cancer is essential for effective treatment. However, current prostate cancer screening methods lack sufficient sensitivity and specificity, leading to overdiagnosis and unnecessary treatment. There is also an unmet need to distinguish clinically significant from insignificant prostate cancer. To identify complementary biomarkers for improved screening and diagnosis, we performed transcriptional profiling of cancer-associated transcripts in circulating extracellular vesicles (EVs) isolated from peripheral blood of patients with suspected prostate cancer prior to biopsy and healthy donors. Expression data for 2549 mRNAs were obtained from 28 men. CAPN5 expression was significantly lower, whereas BIRC2, CASP3, CD63, FMO5, IRF6, PFDN1, PRDX6, PSMD2, RIT1, S100A2, THBS1, and XRCC2 were significantly elevated in EVs from patients with significant prostate cancer (n = 14) compared with cancer-free individuals and patients with insignificant disease (n = 14). Candidate biomarkers were subsequently evaluated by in silico validation using the The Cancer Genome Atlas (TCGA) prostate adenocarcinoma dataset and the GEO dataset GSE70768 containing benign and malignant prostate tissues. This analysis identified CASP3, XRCC2, and RIT1 transcripts in circulating EVs as promising biomarkers for the early detection of significant prostate cancer.

BACKGROUND AND OBJECTIVE:Prostate-specific membrane antigen (PSMA) radioligand imaging allows early detection of recurrence of prostate cancer (PC). While circulating tumor cells (CTCs) have proven prognostic value in metastatic castration-resistant PC, data for the hormone-sensitive setting are limited. The prospective BioPoP study investigated the prognostic value of CTCs before PSMA-based radioguided salvage surgery (PSMA-RGS) in patients with oligorecurrent PC after radical prostatectomy. METHODS:The prospective study cohort included 148 patients undergoing 99mTc-based PSMA-RGS between 2020 and 2024. CTCs were measured preoperatively using a CellSearch system. The primary endpoint was the complete biochemical response (cBR; prostate-specific antigen [PSA] <0.2 ng/ml) rate at 6 mo after PSMA-RGS. Secondary endpoints included biochemical recurrence-free survival (BCR-FS) and PC-specific treatment-free survival (TFS). KEY FINDINGS AND LIMITATIONS:Median PSA before surgery was 0.58 ng/ml (interquartile range [IQR] 0.35-1.08). Most patients exhibited one positive lesion (67%) located within the pelvis (81%). Only 21 patients (14%) were CTC-positive, and three patients had five or more CTCs/7.5 ml blood. The median number of lymph node metastases was 2 (IQR 1-3). The cBR rate at 6 mo was 53% (95% confidence interval [CI] 46-62%) overall, and 51% in CTC-positive group versus 65% in the CTC-negative group (p > 0.05). Median BCR-FS was 7.1 mo (95% CI 4.9-12.4) and median TFS was 42.4 mo (95% CI 37.4-not reached). Exploratory analyses revealed that the group with five or more CTCs/7.5 ml had worse TFS (10.7 vs 42.2 mo for less than five CTCs/7.5 ml). The main limitations are the small number of patients with higher CTC counts and the single-arm design. CONCLUSIONS AND CLINICAL IMPLICATIONS:High CTC counts may potentially predict inferior outcomes after salvage lymph node dissection. As high counts are rare in early oligorecurrent PC, more sensitive CTC technologies and additional biomarkers are needed. The BioPoP study is registered on ClinicalTrials.gov as NCT04324983.

Immunotherapies such as anti-PD-L1 antibodies have transformed cancer treatment, but their effectiveness in gastrointestinal tumors remains limited. One reason may be the absence of reliable prognostic markers that can identify patients at risk and those likely to benefit from such therapies. Circulating tumor cells (CTCs) have therefore gained attention as potential clinical markers for assessing tumor burden and immune status. In this study, 105 patients with esophageal, gastric, or colorectal cancer were enrolled preoperatively. CTCs were isolated and enumerated from venous blood using CellSearch, and PD-L1 expression was assessed. Lymphocytes were enriched via Percoll gradient centrifugation and analyzed by multiparametric flow cytometry. Statistical associations were evaluated using Chi-square tests. CTCs were detected in 16.2% of patients, and among these, 35.3% exhibited PD-L1+CTCs. The presence of PD-L1+CTCs correlated with indicators of advanced disease, including tumor stage, metastasis, and vascular invasion. Additionally, patients who were CTC-positive, and especially those with PD-L1+CTCs, showed reduced immunocompetence, reflected by lower immune cell frequencies, suggesting a weakened systemic immune response. These findings indicate that PD-L1+CTCs reflect tumor-driven immune suppression and may facilitate metastatic spread. Therefore, PD-L1+CTCs should be considered as promising prognostic biomarkers and may provide a rationale for early immunotherapy.

Abstract Most patients with cancer of unknown primary (CUP) still receive platinum-based chemotherapy and have a poor prognosis, with overall survival of less than one year. Recent studies suggest improved outcomes with molecularly guided or site-specific therapies informed by molecular tissue profiling. Here, we analyzed ctDNA from 190 CUP patients using an integrated genomic and epigenomic assay to identify actionable alterations and predict tissue-of-origin (ToO). Integration of actionable biomarkers, ToO prediction and clinical data yielded diagnostic, prognostic or therapeutic information in 90% of unfavorable CUP cases and 88% of patients analyzed at first diagnosis. High ctDNA tumor fraction was associated with poorer prognosis in both favorable and unfavorable CUP. These findings highlight the clinical utility of ctDNA analysis for therapeutic decision-making in CUP and support its incorporation into the diagnostic work-up, particularly when tissue samples are unavailable or insufficient for molecular testing.

9572 Background: Immune checkpoint inhibitors (ICIs) have markedly improved outcomes in melanoma and are now standard of care in advanced and adjuvant settings. However, substantial toxicities remain, and up to 50% of patients derive no clinical benefit. Conventional clinicopathological factors lack sufficient precision for risk stratification, resulting in under- and overtreatment. Circulating tumor DNA (ctDNA) has emerged as a highly specific biomarker for molecular residual disease (MRD) detection, enabling real-time, minimally invasive monitoring to guide personalized ICI strategies. Methods: We analyzed 847 plasma timepoints from 98 melanoma patients treated with ICI in either the unresectable advanced (metastatic) setting (25 patients) or adjuvant setting following complete resection of the primary and/or loco-regional metastases (73 patients). Plasma samples were analyzed using NeXT Personal, a whole-genome-sequencing-based tumor-informed assay designed to track up to 1,800 patient-specific variants. This ultrasensitive liquid biopsy approach achieves detection limits of down to ~1 part per million (PPM) at high specificity (>99.9%), enabling identification of MRD and early molecular relapse that may inform timely therapeutic intervention. Results: Baseline ctDNA was detected in 100% of 25 patients with unresectable melanoma. Within this group, an early molecular response defined by a ≥30% decrease in ctDNA by cycle 3 predicted an 80% reduction in the risk of progression or death (PFS HR 0.2, P=0.01; OS HR 0.2, P=0.03). In the adjuvant cohort, landmark ctDNA positivity at 3 months post-surgery prior to immunotherapy, was 35% and identified patients with significantly inferior outcomes, with a >3-fold increase for the risk of distant metastasis or death (DMFS HR 3.8, P=4.9510−3; OS HR 4.1, P=3.61×10−3). Longitudinal monitoring further established that any ≥20% increase in ctDNA during adjuvant treatment was highly prognostic of poor survival (DMFS HR 3.0, P=0.01; OS HR 3.5, P=0.02). These molecular increases identified recurrences a median of 212 days prior to radiographic detection. The clinical necessity of ultrasensitive assays was underscored by the fact that 71% of these early detections occurred at ultra-low levels below 100 PPM. Real-time variant tracking revealed mutations druggable mutations such as BRAF V600E. Conclusions: Detection of MRD with PPM sensitivity represents a major advance in treatment monitoring for both unresectable and completely resected melanoma. Early on-treatment ctDNA decreases identify responders in advanced disease, while postoperative ctDNA positivity identifies adjuvant patients at highest relapse risk. Early MRD-based detection of loco-regional or distant relapse enables timely adaptation of therapeutic strategies.

Advanced oesophageal neuroendocrine carcinoma (ENEC) is a highly aggressive and rare malignancy with poor prognosis. Due to the rarity of this cancer there are currently no standardised treatment regimens for ENEC, and models to study this disease are difficult to obtain. To address this, we screened our established circulating tumour cell line from a patient with metastatic ENEC, termed UWG01CTC, using the LOPAC®1280 drug repurposing library. The redox modulatory agent adaphostin was identified as a potent cytotoxin against UWG01CTC but not non-ENEC cell lines. Secondary adaphostin cell viability screens returned IC50 values of 0.201 ± 0.024 µM confirming the high sensitivity of this ENEC CTC line to the drug. Inclusion of the antioxidant N-acetyl cysteine significantly protected the UWG01CTCs against the cytotoxic effects of adaphostin (IC50 = 0.928 ± 0.425 µM), corroborating a mechanism mediated through the generation of reactive oxygen species (ROS). The expression of DNA damage marker phospho-γH2AX and apoptotic marker cleaved PARP1 were both elevated in cells treated with adaphostin, suggesting that the increased intracellular ROS levels induced by the drug causes downstream DNA damage and ultimately apoptosis. Thus, adaphostin shows promise as a potential new and selective treatment for ENEC.

TPS646 Background: Current research on circulating tumor DNA (ctDNA) in the adjuvant setting of early breast cancer (eBC) demonstrates its strong prognostic significance. Patients who are ctDNA-positive in the absence of radiological evidence of disease recurrence (i.e., molecular relapse) have significantly reduced disease-free and overall survival. Secondary adjuvant intervention trials employing highly potent therapeutic agents represent an innovative and promising strategy to intercept disease recurrence at the molecular stage. Methods: SURVIVE HERoes is a phase III, randomized clinical trial comparing the antibody–drug conjugate trastuzumab deruxtecan (T-DXd) with standard of care (SoC) in patients with molecular residual or recurrent disease. Eligible patients must have a positive circulating tumor DNA (ctDNA) result detected using a tumor-informed assay (RaDaR), while staging examinations show no evidence of residual or recurrent disease. Participants must have HER2-positive, HER2-low, or—following an approved study amendment—HER2-ultralow early breast cancer (eBC), irrespective of hormone receptor (HR) status, and must have completed primary therapy, including surgery with R0 resection, with or without chemotherapy and/or radiotherapy. 180 participants are randomized in a 2:1 ratio to receive T-DXd (+ endocrine therapy for HR positive patients) or standard of care for 48 weeks, followed by a 48-week follow-up phase. Stratification factors include hormonal receptor status (positive versus negative) and HER2-status (positive versus low versus ultralow). Staging examinations and ctDNA assessments will be performed every 12 weeks during the 2-year study phase per patient. The study is accompanied by a comprehensive translational research program. The primary endpoint is the ctDNA clearance rate after 48 weeks, comparing participants in the experimental arm (receiving T-DXd) with those in the control arm (receiving standard of care), irrespective of ctDNA test results at other time points. Secondary endpoints include invasive disease-free survival, overall survival, ctDNA clearance at other time points, safety, and quality of life (QoL), as assessed by EORTC QLQ-C30 and PA-F12. Recruitment: Recruitment began in Q2/2025 and is anticipated to continue until 2030. Fifty sites across Germany are planned for participation. Discussion: Treating ctDNA-positive patients without radiographic evidence of recurrence is a novel therapeutic strategy. If SURVIVE HERoes and similar studies targeting molecular relapse yield positive results, they could pave the way for a new molecularly driven personalized surveillance and treatment approach. Clinical trial information: NCT06643585 .

Despite substantial clinical benefit from immune checkpoint inhibitors (ICI), advanced melanoma remains challenging due to frequent treatment resistance. Resistance may be intrinsic (primary) or emerge over time (secondary). Biomarkers predicting distinct resistance phenotypes before therapy are lacking. As key mediators of cellular communication, extracellular vesicles (EVs) represent promising biomarkers. This study aimed to identify baseline EV proteome-derived pathways and biomarkers associated with overall, primary, and secondary resistance to ICI in advanced melanoma and to derive biomarker signatures predictive of progression-free survival (PFS). EVs were isolated from pretreatment plasma samples of 46 patients with advanced melanoma using size exclusion chromatography and ultracentrifugation. Proteomic profiling was performed by liquid chromatography-mass spectrometry using DIA-NN. Pathway enrichment and network analyses were conducted using Reactome, Metascape, Cytoscape, and DAVID. Resistance-associated proteins were integrated into composite biomarker signatures and evaluated for association with PFS. Overall resistance was characterized by enrichment of platelet- and complement-associated pathways. Primary resistance was associated with enhanced Fc gamma receptor (FCGR) signaling and downregulation of KSRP-associated post-transcriptional regulatory processes. In contrast, secondary resistance was preceded by distinct baseline EV proteomic patterns involving complement activation and reduced hemostasis- and platelet-related pathways. EV-derived biomarker signatures for overall, primary, and secondary resistance independently discriminated patients according to PFS. Baseline plasma EV proteomics reveals distinct systemic biological programs associated with different resistance phenotypes to ICI in advanced melanoma. EV-derived biomarker signatures enable stratification by PFS and warrant validation in larger, multicentric cohorts.

Persistent high-risk human papillomavirus (hr-HPV) infection drives cervical carcinogenesis, yet improved molecular biomarkers are needed to define high-risk groups. Circulating microRNAs (miRNAs), stable in blood and involved in carcinogenic pathways, represent promising liquid biopsy biomarkers. This study assessed five miRNAs for distinguishing high-grade squamous cell intraepithelial lesions (HSILs) and cervical cancer from healthy controls and for HPV stratification. Circulating miRNAs were quantified in blood samples from 80 women (38 HSIL, 10 cervical cancer, and 32 controls). Relative expression by disease and HPV status was measured by RT-qPCR and normalized to miRNA-23a. Diagnostic performance of single and combined miRNAs was evaluated by logistic regression and ROC curve analysis. Three circulating miRNAs (miR-21, miR-205, and miR-218) were found to be significantly differentially dysregulated in the patient cohorts. A combination of the three markers showed the best diagnostic value for HSIL (AUC of 0.81, sensitivity of 79%, and specificity of 71%) and cancer (AUC of 0.81, sensitivity of 90%, and specificity of 65%). Whereas miR-205 was significantly associated with HPV16/18 in HSIL patients, the combined model had the highest diagnostic performance for multiple HPV infections. Circulating miRNA signatures show promise as liquid biopsy biomarkers for detecting cervical dysplasia and stratifying for HPV status in HSIL, warranting validation in larger prospective studies.