This study provides critical biomarker insights for precision therapy in Epstein-Barr virus-associated gastric cancer (EBVaGC), suggesting that combined assessment of PD-L1 and CD8 may optimize patient stratification strategies and directly guide the design of translational research in related fields.
Literature Overview
The article titled 'Neoadjuvant toripalimab plus CapeOX in locally advanced Epstein-Barr virus-associated gastric or gastroesophageal junction adenocarcinoma: a phase Ⅱ trial,' published in the journal Nature Communications, systematically investigates the efficacy and safety of neoadjuvant toripalimab combined with CapeOX chemotherapy in patients with locally advanced EB virus-associated gastric or gastroesophageal junction adenocarcinoma (EBVaGC). The study employs a prospective design focusing on this rare molecular subtype characterized by a unique immune microenvironment, aiming to evaluate the major pathological response (MPR) rate and explore potential predictive biomarkers. The results reveal a high pathological response rate and suggest that PD-L1 expression and CD8⁺ T cell density may be associated with treatment response.Background Knowledge
Epstein-Barr virus-associated gastric cancer (EBVaGC) accounts for approximately 4.4%–10% of all gastric cancers and is characterized by prominent lymphocytic infiltration and frequent PD-L1 amplification, suggesting potential sensitivity to immune checkpoint inhibitors (ICIs). However, while early studies indicated a high objective response rate to ICI monotherapy in EBVaGC, subsequent findings have been inconsistent, and the survival benefit of ICIs in advanced disease remains unclear. Currently, the reliability of PD-L1 as a predictive biomarker in EBVaGC is controversial, partly due to tumor heterogeneity and the lack of standardized preoperative molecular subtyping. Moreover, while the central role of CD8⁺ T cells in anti-tumor immunity is well established, their dynamic changes during neoadjuvant immune chemotherapy in EBVaGC and their relationship with pathological response have not been fully elucidated. This study focuses on systematically evaluating the efficacy of neoadjuvant toripalimab plus CapeOX in patients with locally advanced, resectable EBVaGC, and uses multiplex immunofluorescence analysis of paired tissue samples to deeply investigate baseline characteristics and treatment-induced changes in key immune cell subsets within the tumor immune microenvironment (TIME), aiming to identify reliable predictive biomarkers.
Research Methods and Experiments
The study adopted a single-arm, open-label, phase Ⅱ clinical trial design (NCT04744649), enrolling 17 patients with histologically confirmed locally advanced EBVaGC who received four cycles of neoadjuvant toripalimab (an anti-PD-1 antibody) combined with CapeOX chemotherapy. All patients underwent diagnostic laparoscopy and peritoneal lavage cytology to exclude peritoneal metastasis. The primary endpoint was the major pathological response (MPR) rate, defined as ≤10% residual viable tumor cells in the resected specimen. Key components of the experimental system included: 1) confirmation of EBV status in all enrolled patients by a central laboratory using Epstein-Barr virus-encoded small RNA (EBER) in situ hybridization; 2) assessment of PD-L1 combined positive score (CPS) using the 22C3 antibody via immunohistochemistry (IHC); 3) multiplex immunofluorescence (mIF) staining on paired pre- and post-treatment tumor tissues from 11 patients to quantitatively analyze the spatial distribution and density of immune cells, including CD8⁺ T cells and CD68⁺CD163⁻ M1 macrophages. Pathological evaluations were performed blindly by two independent gastrointestinal pathologists to ensure objectivity.Key Conclusions and Perspectives
Research Significance and Prospects
This study prospectively confirms the significant efficacy of neoadjuvant immune chemotherapy in locally advanced EBVaGC, providing high-level evidence for perioperative management in this specific molecular subtype. From a research perspective, it underscores the importance of integrating baseline immune features (such as PD-L1 and CD8⁺ T cells) with dynamic immune monitoring, laying the foundation for future biomarker-driven precision therapeutic strategies.
Conclusion
This study marks a pivotal step toward precision medicine in the treatment of Epstein-Barr virus-associated gastric cancer. By prospectively validating the feasibility and high pathological response rate of neoadjuvant toripalimab combined with CapeOX, it not only offers a new treatment option for clinical practice but, more importantly, reveals the value of PD-L1 and CD8⁺ T cells as potential predictive biomarkers. These findings suggest that in the future, routine EBV and PD-L1 testing should be implemented in the perioperative management of EBVaGC, with consideration given to incorporating immune microenvironment analysis to identify patient populations most likely to benefit from immune chemotherapy. From bench to bedside, this study establishes a complete chain linking molecular subtyping to treatment response, providing a solid foundation for optimizing care in this disease and advancing the era of personalized therapy. Subsequent large-scale, multicenter studies will help further validate the clinical utility of these biomarkers and explore combination targeted strategies to overcome primary or acquired resistance.
