Introduction:Circulating immune cells serve as readily accessible biomarkers in cancer patients. Some of them, such as neutrophils, lymphocytes as well as the neutrophil to lymphocyte ratio (NLR), have been validated as prognostic indicators of disease outcome whereas the significance of others remains controversial due to conflicting findings. Moreover, the interplay and correlation among these markers have not been thoroughly investigated nor has their dynamic course during chemotherapy. Methods:Blood was collected from 16 healthy donors and 90 patients receiving first line chemotherapy for metastatic colorectal cancer before, during and after chemotherapy. Neutrophils, lymphocytes, circulating CD4+CD25+FOXP3+ regulatory T lymphocytes (Tregs), monocytic myeloid derived suppressor cells (mMDSCs), polymorphonuclear myeloid derived suppressor cells (pMDSCs) and other exploratory myeloid subsets were immunophenotyped and quantified with flow cytometry. Their frequencies were compared between healthy donors and patients and correlated with each other and with clinical parameters. Associations with progression-free and overall survival were evaluated using Cox proportional hazards regression and longitudinal changes in immune cell populations during chemotherapy were analyzed using linear mixed-effects models. Results:Circulating Tregs were significantly reduced in patients with high neutrophil counts (7% vs 17%, p=0.04), increased significantly during treatment in responders, particularly in patients achieving complete or partial response (+16%, p = 0.003) but did not demonstrate prognostic significance. pMDSCs were further stratified by CD16 expression into a CD16+ subset associated with favorable outcome and a CD16dim/- subset enriched in patients demonstrating poor prognosis. Frequency of circulating mMDSCs was modestly increased in patients but retained adverse prognostic significance (HR 1.98, CI 1.04-3.78, p=0.039) and correlated with the CD16dim/- pMDSC fraction. Mature CD15+CD33- polymorphonuclear cells were significantly expanded in patients (79% vs 73%, p=0.003) and correlated with adverse clinical features, whereas lower levels correlated with improved survival (HR 0.54, CI 0.3-0.98, p=0.045). Rare HLA-DR+CD16+ granulocytic subset demonstrated significantly reduced levels in patients compared to healthy donors while their kinetics during treatment also correlated inversely with disease burden. Discussion:Circulating immune cell subsets in metastatic colorectal cancer exhibit considerable baseline heterogeneity and distinct immune kinetics during chemotherapy. Our findings demonstrate that conventional leukocyte populations, when evaluated individually, together with detailed immunophenotyping provide complementary prognostic information, revealing previously unappreciated heterogeneity within major immune cell populations and a network of novel interrelationships among circulating immune cells. Together, these observations support comprehensive immune profiling as a promising approach for future biomarker development and immune-based patient stratification.

In breast cancer, current knowledge of the associations between clinicopathologic characteristics, genetic changes, and subtype-specific patterns remain unclear. This research investigated how pathological and clinical variables affect the actionability of NGS-based tumor molecular data. Materials and methods: 227 breast cancer patients referred to Genekor’s laboratory for tumor molecular profile analysis were included in the study. Pathology records, available in all cases, were used to assess critical clinicopathological features including HER2, ER, PR, Ki67, grade, metastatic site, and age. A 1021 gene NGS-based multigene panel was utilized to assess tumors’ biology alongside tumor mutational burden (TMB) and microsatellite instability (MSI) Results: Comprehensive genomic profiling revealed that 95.6% of the patients harbored at least one oncogenic or likely oncogenic alteration, highlighting the high diagnostic yield of NGS-based testing. Distinct subtype-specific patterns were observed: HR+/HER2-tumors were enriched for PIK3CA and ESR1 gene alterations, while Triple Negative Breast Cancer (TNBC) was dominated by TP53 alterations. Clinically actionable alterations were most common in HR+/HER2-tumors (~60% on-label), whereas TNBC more often harbored off-label or trial-associated targets. The inclusion of tumor-agnostic biomarkers (TMB/MSI) increased on-label actionability up to 64.5% in ER−/PR+ tumors. primarily driven by TMB-high cases. Median TMB values were low, and age was the only independent predictor. Furthermore, the presence of actionable alterations was significantly higher in metastatic tumors, and TP53 alterations were associated with aggressive tumor characteristics.Conclusions: Comprehensive NGS-based genomic profiling identifies clinically actionable alterations in over half of breast cancer patients, with substantial variability across molecular subtypes. The HR+/HER2-subtype demonstrates the highest prevalence of on-label actionable biomarkers. These findings support the routine implementation of comprehensive genomic profiling, especially in metastatic HER2-negative breast cancer, to guide precision oncology strategies and enable enrollment in biomarker-driven clinical trials.

Immunotherapy has revolutionized the management of patients with cancer. Immune checkpoint inhibition (ICI) is a promising treatment option that targets the molecular mechanisms that cancer cells exploit to prevent immune-mediated elimination. ICI therapy can cause exceptional long-term tumor remissions, in some cases, even after treatment discontinuation. Despite its success, many patients acquire resistance or fail to respond due to immune escape mechanisms mediated by the tumor and its microenvironment. Pre-existing immunity status of individuals seems to play a fundamental role in immunotherapy response and eventually tumor progression, as it orchestrates tumor-immune interactions. Different immune cell subsets, both in the tumor microenvironment and the peripheral blood, are established mediators that contribute to immune escape in various tumor types. Based on these findings, the elucidation of the mechanisms implicated in the regulation of these immune cells has become a priority for investigators focused on improving the efficacy of ICI. This will be essential for identifying responders as well as for developing novel therapeutic modalities to improve clinical outcomes. Herein, we summarize preclinical and clinical evidence proposing a predictive role of pre-existing immunity for clinical responses to immunotherapies.

Background/Objectives: Advanced prostate cancer (PCa) evolves through adaptive mechanisms that sustain tumor growth despite the suppression of androgen receptor (AR) signaling. Accumulating evidence identifies activation of the hepatocyte growth factor (HGF)/MET pathway as a potential driver of PCa progression in advanced disease states characterized by AR-independence and therapeutic resistance. We review the biological and clinical evidence supporting MET as a context-dependent therapeutic target and discuss its implications for patient selection and combination strategies. Methods: A comprehensive narrative review of preclinical, translational, and clinical studies evaluating MET-directed therapies for PCa was performed. Results: Aberrant activation of the HGF-MET axis is frequently driven by autonomous paracrine and autocrine loops that sustain pathway activation during disease progression. MET overexpression is associated with adverse pathological features, increased tumor aggressiveness, bone metastasis, lineage plasticity, and resistance to AR-targeted treatments. Preclinical studies have demonstrated that AR suppression, tumor hypoxia and tumor-microenvironment interactions promote MET upregulation, supporting AR-independent growth and epithelial-to-mesenchymal transition. Clinical trials of MET inhibitors have shown modest activity as monotherapies, with the most consistent biological effects observed in bone-dominant disease. Recent studies indicate greater therapeutic potential when MET inhibition is incorporated into rational combination strategies targeting complementary molecular pathways. Emerging data further indicate that MET activation characterizes a biologically aggressive, AR-low or neuroendocrine-like disease state. These findings support a transition from empiric use of MET inhibitors toward precision, context-driven therapeutic development. Conclusions: MET is not a universal therapeutic target but defines a clinically relevant subset of aggressive, AR-indifferent PCa. Future development should focus on biomarker-guided patient selection and rational combination strategies. Integration of molecular profiling, imaging, and liquid biopsy approaches will be essential to identify patients most likely to benefit from MET-directed interventions.

Circulating tumor DNA (ctDNA) has emerged as a transformative biomarker in lung cancer management. Its clinical applications span from the well-established role in therapy selection for advanced non-small cell lung cancer (NSCLC) to rapidly evolving uses in treatment response monitoring, minimal residual disease (MRD) detection, perioperative immunotherapy assessment, and early cancer detection. This review synthesizes the current evidence and future perspectives on ctDNA across the lung cancer care continuum, highlighting key clinical trials, guideline recommendations, technological advances, and remaining challenges for broader clinical implementation.

BACKGROUND:Chemotherapy-related symptom burden and psychological distress may significantly influence patients' perceptions of treatment convenience and satisfaction, yet evidence in the Greek oncology population remains limited. METHODS:A cross-sectional study was conducted among 150 cancer patients receiving chemotherapy in a tertiary hospital. Data were collected using CCSQ, ESAS-r, PHQ-2, GAD-2, and WHO-5. Pearson correlations and multiple linear regression analyses were performed. RESULTS:Higher levels of depressive symptoms and anxiety were significantly associated with lower chemotherapy convenience and satisfaction (e.g., PHQ-2: r = -0.659 to -0.584, p < 0.001; GAD-2: r = -0.623 to -0.469, p < 0.001). Depressed mood emerged as a significant negative predictor of convenience (β = -0.39, p = 0.015) and concerns (β = -0.39, p = 0.005), while anxiety independently predicted satisfaction (β = 0.45, p = 0.007). CONCLUSIONS:Chemotherapy experience is strongly associated with psychological and symptom burden. These findings highlight the importance of integrating psychosocial assessment into routine oncology care.

Background: Small-cell lung cancer (SCLC) is an aggressive type of lung cancer, and several factors are currently used to predict poor outcomes, including performance status (PS), extensive-stage disease, male sex, advanced age, and elevated lactate dehydrogenase (LDH) levels. In this study, we aimed to explore the role of Tegs and inflammatory indices, such as CRP and NLR, in predicting response to immunotherapy. Methods: Fifty-one therapy-naïve ES-SCLC patients and ten healthy donors were enrolled. Peripheral blood mononuclear cells (PBMCs) were isolated and stained with fluorochrome-conjugated monoclonal antibodies. Multicolor flow cytometry was performed to determine the levels of CD8+ T cells and CD4+ Tregs, as well as their correlation with inflammatory indices and clinical outcomes. Results: ES-SCLC patients harbored higher percentages of CD8+ Teffs (p = 0.005) and FOXP3+ Tregs (p < 0.0001) in circulation before therapy compared with healthy donors. In addition, high levels of CD3+CD8+ T effectors were associated with longer PFS (p = 0.018) and longer OS (p = 0.012) compared with patients bearing low levels, while Tregs were not found to be predictive. More importantly, a survival benefit was observed in ES-SCLC patients with a low Treg/Teff ratio, as longer OS was observed in those with high percentages of CD8+ Teffs and low FOXP3+CTLA-4+ Tregs (p = 0.014) compared with those bearing low CD8+ Teffs and high FOXP3+CTLA-4+ Tregs. A low Treg/Teff ratio was further associated with low eosinophil levels and a low NLR before treatment initiation. Conclusions: These findings suggest a novel, easily obtainable blood-based signature that may help predict response to ICIs in ES-SCLC patients.

Background: Immune checkpoint blockade (ICB) targeting the PD-1/PD-L1 axis has improved outcomes in non-small cell lung cancer (NSCLC), although reliable biomarkers for predicting benefit are still limited. Methods: In this exploratory study, we conducted a longitudinal analysis of the peripheral T-cell receptor (TCR) β repertoire in 28 patients with unresectable stage IIIb non-small cell lung cancer (NSCLC) who received anti-PD-L1 immunotherapy following chemoradiotherapy. Blood samples were collected at baseline and three months after treatment initiation. Results: At the cohort level, global TCR repertoire features such as diversity and richness did not change significantly over time. However, when looking at individual patients, more specific patterns became evident. Patients could be broadly separated based on changes in clonotype richness, with reductions generally accompanied by lower diversity and decreased convergent TCR frequency. We also observed differences in TRBV gene usage in relation to clinical outcome, with higher TRBV20-1 and lower TRBV28 frequencies tending to associate with improved survival and delayed disease progression. Interestingly, the disappearance of dominant clonotypes from the peripheral blood during treatment was linked to longer progression-free survival (PFS). In addition, patients with higher baseline blood plasma tumor mutational burden (bTMB) showed greater clonotype richness and were more likely to exhibit this clonotype loss. The combination of high bTMB and clonotype disappearance identified a subgroup of patients with particularly favorable outcomes. Conclusions: Overall, these results suggest that early responses to PD-L1 blockade may be reflected less in global TCR repertoire shifts, including clonality and diversity measures, and more in subtle changes in clonotype composition and dynamics, since the frequencies of certain TRBV genes and the disappearance of dominant clonotypes following ICB were associated with clinical outcomes integrating TCR profiling with bTMB and could therefore help refine patient stratification and improve the understanding of immune responses in NSCLC. Nevertheless, due to the small number of recruited patients, our study is exploratory and hypothesis-generating, and further validation in larger patient cohorts is warranted.

11010 Background: Cancer-related cognitive impairment (CRCI, “chemobrain”) is a common condition among patients (pts) receiving adjuvant chemotherapy (CT) and has been shown to negatively affect quality of life (QoL). However, the clinical relevance of early CRCI beyond symptom burden remains poorly characterized. We evaluated whether early CRCI is associated with compromised delivery of adjuvant CT, including reduced relative dose intensity (RDI). Methods: This prospective study was conducted at the University Hospital of Larissa and represents an expanded analysis of a previously reported population with treatment delivery endpoints. Pts with early stage (ES) breast (BC) or colorectal (CRC) cancer scheduled to receive adjuvant CT containing taxanes or oxaliplatin, respectively, were eligible for this study (C1). Two control groups were included: ES cancer pts that were not eligible for adjuvant CT (C2) and age-matched healthy controls (C3). Eligibility criteria included age > 45 years and fluency in Greek; pts with pre-existing dementia or anxiety disorders were excluded. C1 pts were assessed at baseline and every 3 months (mo) up to 12 mo after CT initiation, while C2 and C3 were assessed at 3-mo intervals. CRCI was evaluated using the Greek Version of Functional Assessment of Cancer Therapy-Cognitive Function (FACT-Cog). Early CRCI was defined as a ≥10-point decline in total FACT-Cog score at 3 mo after CT initiation, in the absence of severe anemia (CTCAE grade ≥3). Treatment delivery outcomes included RDI (reduced RDI: < 85%), treatment delays, CT discontinuation, unplanned healthcare use and CT-related neurotoxicity (ntx). Results: Overall, 164 pts were included in C1 (111 BC, 63 CRC), 61 in C2 (38 BC, 23 CRC) and 25 in C3. Early CRCI was observed in a substantial proportion of pts receiving adjuvant CT (99/164, 60%). Pts with early CRCI were significantly more likely to receive reduced CT dose intensity compared to those without CRCI (OR 3.27, 95% CI 1.34-7.98). Early CRCI was also associated with an increased risk of clinically relevant concurrent treatment-related ntx (CTCAE grade > 1; OR 4.05, 95% CI 1.81-9.08). CT discontinuation occurred more frequently among pts with early CRCI than among those without CRCI (12% vs 3%). In addition, these pts more frequently experienced treatment delays and unplanned healthcare use. These associations were independent of baseline ECOG PS. Early CRCI persisted beyond 3 mo in a substantial proportion of affected pts during follow up, while cognitive scores remained stable among controls. Conclusions: In this expanded cohort, early CRCI was associated with reduced RDI and higher rates of treatment discontinuation. Beyond its impact on QoL, early CRCI identifies a vulnerable subgroup of pts at risk for compromised treatment delivery and may represent a clinically actionable target for risk-adapted supportive strategies aimed at preserving curative-intent treatment intensity.

Background Artificial intelligence (AI) has the potential to improve cancer care. Its implementation must align with patients’ needs, values, and lived experiences. This study aimed to explore perspectives from patient advocates representing patient organizations, including individuals with experience of melanoma, bladder and lung cancer, and to co-develop recommendations to support the ethical, patient-centered, and practical integration of AI in oncology. Methods Semi‑structured interviews were conducted with 18 patient advocates from patient organizations within the MULTIR network to explore current challenges in cancer care, perceptions of the benefits and risks of AI, and conditions for its trustworthy, sustainable and equitable adoption. Findings were reviewed and refined through a series of webinars, enabling participants to validate and strengthen the resulting recommendations. Results Participants identified key benefits and risks associated with AI and formulated six main recommendations targeting developers, policymakers, regulators, and researchers. These include: ensuring clear, accessible, and transparent communication about AI; strengthening training and capacity-building for healthcare professionals and patient organizations; demonstrating tangible clinical and patient-level benefits; developing secure, robust, and interoperable data infrastructures; reinforcing ethical and regulatory frameworks; and ensuring the sustained and meaningful involvement of patient organizations throughout AI development, implementation, and evaluation processes. Conclusion These recommendations provide actionable, patient-informed directions for advancing the integration of AI in cancer care. Although grounded in insights from specific cancer communities, they are broadly applicable across oncology. Progress will require the structured integration of patient organizations and experiential knowledge into governance, research, and implementation processes, in order to support more equitable, trustworthy, and patient-centered AI-enabled health systems. Policy Summary The recommendations have implications for European policies on healthcare regulation, digital health infrastructure, and data governance. They highlight the importance of capacity building, stakeholder engagement, and embedding principles of equitable access, responsible implementation, and patient‑centered governance of AI‑enabled health services.

BACKGROUND/AIM:In breast cancer, knowledge of the associations between clinicopathologic characteristics, genetic changes, and subtype-specific patterns is expanding. This study investigated how pathological and clinical variables affect the actionability of Next Generation Sequencing (NGS)-based tumor molecular data. MATERIALS AND METHODS:227 breast cancer patients referred to Genekor's laboratory for tumor molecular profile analysis were included in the study. Pathology records were used to assess critical clinicopathological features, including HER2, ER, PR, Ki67, grade, metastatic site, and age. A 1021-gene NGS-based multigene panel was utilized to assess tumor biology alongside tumor mutational burden (TMB) and microsatellite instability (MSI). RESULTS:Comprehensive genomic profiling revealed that 95.6% of the patients harbored at least one oncogenic or likely oncogenic alteration, highlighting the high diagnostic yield of NGS-based testing. Distinct subtype-specific patterns were observed: HR+/HER2- tumors were enriched for PIK3CA and ESR1 gene alterations, whereas triple-negative breast cancer (TNBC) was dominated by TP53 alterations. Clinically actionable alterations were most common in HR+/HER2- tumors (~60% on-label), whereas TNBC more often harbored off-label or trial-associated targets. The inclusion of tumor-agnostic biomarkers (TMB/MSI) increased on-label actionability up to 64.5% in HR+/HER2- tumors, primarily driven by TMB-high cases. Median TMB values were low, and age was the only independent predictor. Furthermore, the presence of actionable alterations was significantly higher in metastatic tumors, and TP53 alterations were associated with aggressive tumor characteristics. CONCLUSION:Comprehensive NGS-based genomic profiling identifies clinically actionable alterations in over half of breast cancer patients, with substantial variability across molecular subtypes. The HR+/HER2- subtype demonstrates the highest prevalence of on-label actionable biomarkers. These findings support the routine implementation of comprehensive genomic profiling, especially in metastatic HER2-negative breast cancer, to guide precision oncology strategies and enable enrollment in biomarker-driven clinical trials.

Introduction:Novel predictive biomarkers are needed to optimize immunotherapy-based treatment response in non-small cell lung carcinoma (NSCLC). T cell modulatory features may limit the ability of T cells to mount effective anti-tumor responses and could predict immune fitness and responsiveness to therapy. We investigated the prognostic and predictive value of CD8+ T cells with an exhausted phenotype, specifically those co-expressing Programmed Death 1 (PD-1) and T cell factor 1 (TCF-1), in peripheral blood of NSCLC patients before any systemic treatment. Methods:Two patient cohorts were analyzed: a) 32 patients with early and locally advanced disease (stage I-IIIA; cohort A) who did not receive immunotherapy, and b) 47 patients with advanced disease (stage IIIB-IV) who received chemo-immunotherapy. Multicolor flow cytometry was used to assess CD8+ T cell subpopulations co-expressing PD-1 and TCF-1. Results:PD-1+TCF1+ progenitor (early) exhausted T cells were found at high frequencies in all NSCLC patients compared with healthy donors, regardless of tumor stage. In cohort A, patients with high levels of CD3+CD8+PD-1+TCF1+ T cells had significantly improved DFS (p= 0.038), while those with high CD3+CD8+PD-1+TCF1- T cells had significantly worse DFS (p= 0.028). In cohort B, high levels of CD3+CD8+PD-1+TCF1+ T cells were associated with shorter PFS (p= 0.027). No association with OS was observed in cohort A. Conversely, in cohort B, high CD3+CD8+PD-1+TCF1+ T cell levels correlated with shorter OS (p= 0.045), while high CD3+CD8+PD-1+TCF1- T cell levels correlated with longer OS (p= 0.010). Conclusion:Therefore, here we show that circulating PD-1⁺TCF1+ T cells correlated differentially with treatment outcome in early and late NSCLC stage patients.

This scoping review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines. It summarizes advances in fibroblast activation protein inhibitor (FAPI) positron emission tomography (PET) for oncologic and fibroinflammatory diseases. FAP is expressed broadly on activated mesenchymal cells—including cancer-associated fibroblasts (CAFs) and myofibroblasts within desmoplastic tumor stroma, FAP-positive tumor cells in selected sarcomas, and activated fibroblasts in chronic fibroinflammatory disorders such as rheumatoid arthritis, Crohn’s disease, and organ fibrosis. By targeting these activated fibroblasts, [68Ga]- and [18F]-labeled FAPI tracers provide high tumor-to-background contrast, particularly in desmoplastic and stromal-rich cancers. Compared with [18F]FDG, FAPI PET demonstrates superior lesion conspicuity in selected malignancies and enables a streamlined, non-fasting imaging workflow. Beyond oncology, FAPI PET is emerging as a promising tool for assessing cardiac fibrosis, pulmonary inflammation, and autoimmune conditions characterized by fibroblast activation. A systematic literature search of PubMed and Scopus was performed for peer-reviewed publications from 1 January 2018 to 28 February 2026. Inclusion criteria encompassed original studies, systematic reviews, meta-analyses, clinical guidelines, case series, and case reports reporting on FAPI-targeted PET in human subjects or translational models, published in English. After screening, 256 sources met the eligibility criteria and are included. The development of standardized SNMMI/EANM imaging protocols, along with ongoing multicenter trials and the first prospective phase 2 clinical trial of 68Ga-FAPI-46 PET with histopathological confirmation, now supports the reproducible implementation of FAPI PET across institutions. FAPI PET demonstrates strong translational potential, largely due to its favorable biodistribution, safety profile, and theranostic flexibility. However, its widespread use in routine clinical practice is contingent upon large-scale clinical validation, structured reader training, and formal regulatory approval. In conclusion, FAPI PET represents a maturing molecular imaging platform targeting activated fibroblasts across oncologic and fibroinflammatory diseases. Its widespread adoption into clinical practice requires large-scale prospective trials, reader training, standardized reporting, and regulatory approval—all of which are now actively underway.

OBJECTIVE:Prostate-Specific Membrane Antigen (PSMA) PET/CT has rapidly become the preferred first-line imaging modality for primary staging of unfavourable intermediate-risk, high-risk, and very high-risk prostate cancer, and for restaging at biochemical recurrence. The objective of this review is to provide nuclear medicine physicians with a comprehensive and practical framework for PSMA PET/CT interpretation, structured reporting, and clinical decision integration, with emphasis on primary staging evidence, biochemical recurrence (BCR) detection rates, imaging pitfalls, and the PSMA-RADS reporting system. METHODS:A narrative review of published evidence was performed, encompassing landmark randomised controlled trials and guideline documents from the EAU, EANM, and NCCN. Key trials reviewed included proPSMA, OSPREY, PRIMARY, CONDOR, and VISION. RESULTS:PSMA PET/CT demonstrated diagnostic accuracy (AUC) of 0.92 versus 0.38 for conventional imaging in primary staging (proPSMA). Detection rates in BCR ranged from 38% at PSA <0.2ng/mL to 97% at PSA >2ng/mL. In a phase 3 RCT, 18F-PSMA-1007 demonstrated superiority over 18F-Choline (84% vs 69%, OR 2.53, p<0.001). CONCLUSION:PSMA PET/CT provides superior staging accuracy, enables detection of recurrence at low PSA levels, guides oligometastasis-directed therapy, and serves as the mandatory gatekeeper for 177Lu-PSMA-617 theranostic eligibility. Structured reporting using PSMA-RADS and rigorous CT correlation - particularly to exclude unspecific bone uptakes (UBUs) with 18F-PSMA-1007 - are core professional competencies of the nuclear medicine physician.

Background: Multigene assays have become a key component in risk stratification of patients with HR+/human epidermal growth factor receptor 2-breast cancer. Among these, the Oncotype DX is a validated tool that predicts the risk of distant recurrence and the potential absolute benefit of adding chemotherapy to adjuvant endocrine therapy. Although breast cancer is less common in younger women, it is often associated with biologically more aggressive features and a worse prognosis. Moreover, this age group has been historically underrepresented in large, randomized clinical trials of Oncotype DX. Hence, younger women are less frequently evaluated with Oncotype DX, and even when testing is performed, the decision to administer chemotherapy is not always aligned with the recurrence score result. Methods: In this retrospective analysis, a total of 358 young patients were stratified into three genomic risk groups (low, intermediate, and high) according to their Oncotype DX Recurrence Score (RS). A subsequent subgroup analysis focused on identifying individuals within the low genomic risk category who were eligible for treatment with the cyclin-dependent kinase 4 and 6 inhibitor ribociclib. Results: Among the patients, 41% were classified as low genomic risk, 44% as intermediate, and 15% as high. Notably, 35% of the pT2 patients with low genomic risk were clinically high risk as per the NATALEE trial criteria. Conclusion: Despite the poorer prognosis in younger women, 41% had a low genomic risk and could potentially be treated effectively with endocrine therapy alone. Among those node-negative patients with tumor size 2–5 cm, one out of three (35%) were classified as clinically high-risk and could benefit from the addition of ribociclib.

e20603 Background: Even though NSCLC prevalence is increasing in the eld population, they are underrepresented in clinical trials, including those involving IO. This study aims to assess the effectiveness and safety of IO as 1 st line treatment in eld pts with NSCLC undergoing CGA. Methods: A prospective study of pts ≥70 years old was performed at the University Hospital of Larissa. Clinical and demographic data were derived from pts’ medical records. Pts were screened (G8 tool) and categorized as fit, vulnerable (vln) and frail by CGA. Immune-related adverse events (irAEs) were graded according to Common Terminology Classification Adverse Events version 5.0. Kaplan-Meier survival curves and Cox regression for PFS/OS between groups were performed. Results: Overall, 129 pts with a mean age of 74.8 (range 70-92) were enrolled. Pts were predominantly male (92%) with squamous histology (50%) that received either monotherapy IO (7%) or chemotherapy+IO (93%). Pts had a G8 mean score of 8.8 (range 2-14) and were categorized as fit (27%), vln (41%) and frail (32%). CGA revealed that 46% of the pts needed assistance with IADLs ; all had ≥1 comorbidities (mean 4; range 1-10) and took ≥1 medications (mean 5; range 1-11); 67% experienced weight loss >3kg in the past 3 months (mo); 14% had cognitive impairment on Mini-Mental State Examination and 7% suffered at least one fall. Both median OS and median PFS were significantly higher in fit pts compared with vln and frail [OS: 30 vs 20 and 5 mo, respectively (resp), p<0.001; PFS: 16 vs 10 and 3 mo, resp, p=0.001]. Pts with Cumulative Illness Rating Scale-Geriatric 3-4 score had significantly shorter PFS/OS (8/13 mo, resp) compared with pts with lower scores (p=0.04/p=0.009, resp). Antiplatelet use (37.2% of pts) was linked to improved PFS/OS (13/20 mo, p=0.036/p=0.036, resp). Pts with a baseline albumin of ≥3.5 g/dL had improved PFS/OS compared to those with <3.5 g/dL (13 vs 5 mo, p<0.01; 20 vs 10 mo, p<0.01, resp). Overall, 30% of the pts experienced severe (grade 3-4) irAEs (SirAEs). Fit pts were at a lower risk for developing a SirAEs (Relative Risk: 0.73). Notably, pts aged ≥75 years had a lower incidence of SirAEs compared to pts <75 years old. Pts that experienced SirAEs exhibited worse survival outcomes compared to pts without (PFS: 7 vs 13 mo, p=0.001; OS: 10 vs 20 mo, p=0.002). Toxicity-related treatment discontinuation rate was higher in frail pts (52.8% vs 23.6%). Conclusions: Although, IO maintains efficacy in eld pts with NSCLC, our findings suggest that frailty, comorbidities and low albumin levels are correlated with worse survival outcomes. Frail pts also experienced more SirAEs and toxicity-related treatment discontinuations. These findings emphasize the necessity of a CGA rather than relying only on chronological age for guiding treatment decisions in the eld population.

4173 Background: In-depth analysis of T-cell exhausted subsets in the circulation of Pancreatic Ductal Adenocarcinoma (PDAC) patients may provide insights into novel therapeutic options and predictive biomarkers. We performed a detailed immunophenotypic analysis for both early-stage (resectable) and metastatic (unresectable) PDAC patients. Additionally, different T-cell populations were correlated with clinical outcome. Methods: Fifty-five treatment naive PDAC patients, twenty-five of which had resectable disease, and ten healthy donors (HD) were enrolled. Peripheral Blood Mononuclear Cells (PBMCs) were isolated and stained with fluorochrome-conjugated monoclonal antibodies. Multicolor flow cytometry was performed to determine differences between T-cell populations and their correlation with clinical outcome. Results: Advanced disease patients that harbored high percentages of CD4 + PD-1 + T eff cells had longer PFS (median: 190 vs. 100 days, p:0.030) and OS (median: 250 vs. 170 days, p:0.041) while for early-stage patients high percentages of CD8 + PD-1 + T eff displayed longer DFS (median: 422 vs. 200 days, p:0.044) and OS (median: Und vs. Und days, p:0.041). For early-stage patients, high percentages of both CD4 + and CD8 + T-cells expressing PD-1 + TCF1 + (exhausted cells) were predictive for survival (CD3 + CD4 + PD-1 + TCF1 + : med. Und vs. 277 days, p:0.0041) and (CD3 + CD8 + PD-1 + TCF1 + : med. Und vs. 390 days, p:0.042). Additionally, expression levels of PD-1 (MFI levels) were substantially elevated in the PD-1 + TCF1 - subset for both early stage CD3 + CD4 + (p:0.026), CD3 + CD8 + (p: = 0.006) and advanced-stage, (p:0.0001 and p:0.045, respectively), implying that terminally exhausted (PD-1 + TCF1 - ) T-cells exhibit higher PD-1 expression than primarily exhausted (PD-1 + TCF1 + ). For advanced stage patients, high levels of CD57 + , a marker of terminally differentiated T-cells, in CD3 + CD8 + were associated with improved PFS (118 vs. 92 days, p:0.178)and OS(271 vs. 152 days, p: 0.019), CD3 + CD8 + PD-1 + TCF1 + ( PFS: med. 260 vs. 60 days, p = 0.0063 ; OS: 271 vs. 90 days, p: 0.003) and CD3 + CD8 + PD-1 + TCF1 - T-cells (PFS: med. 188 vs. 80 days, p = 0.0459 ; OS: 271 vs. 107 days, p = 0.0429). CD57 + T-cells were not correlated with response in early-stage patients. Conclusions: T-cell exhaustion represents ineffective immune response and in both early and advanced-stage PDAC may predict clinical outcome offering opportunities for innovative therapeutic options for this fatal disease.

CXCR4, JUNB and PD-L1 are implicated in cancer progression and metastasis. The current study investigated these biomarkers in CTCs isolated from metastatic prostate cancer (mPCa) patients at the RNA and protein levels. CTCs were isolated from 48 mPCa patients using the Ficoll density gradient and ISET system (17 out of 48). The (CK/PD-L1/CD45) and (CK/CXCR4/JUNB) phenotypes were identified using two triple immunofluorescence stainings followed by VyCAP platform analysis. Molecular analysis was conducted with an EpCAM-dependent method for 25/48 patients. CK-8, CK-18, CK-19, JUNB, CXCR4, PD-L1, and B2M (reference gene) were analyzed with RT-qPCR. The (CK+/PD-L1+/CD45-) and the (CK+/CXCR4+/JUNB+) were the most frequent phenotypes (61.1% and 62.5%, respectively). Furthermore, the (CK+/CXCR4+/JUNB-) phenotype was correlated with poorer progression-free survival [(PFS), HR: 2.5, p = 0.049], while the (CK+/PD-L1+/CD45-) phenotype was linked to decreased overall survival [(OS), HR: 262.7, p = 0.007]. Molecular analysis revealed that 76.0% of the samples were positive for CK-8,18, and 19, while 28.0% were positive for JUNB, 44.0% for CXCR4, and 48.0% for PD-L1. Conclusively, CXCR4, JUNB, and PD-L1 were highly expressed in CTCs from mPCa patients. The CXCR4 protein expression was associated with poorer PFS, while PD-L1 was correlated with decreased OS, providing new biomarkers with potential clinical relevance.