Prognostic implications of tumor-infiltrating lymphocytes within the tumor microenvironment in gastric cancer.

BACKGROUND: Tumor-infiltrating lymphocytes (TILs) play a regulatory role in the tumor-associated immune response and are important in the prognosis and treatment response of several cancers. However, because of its heterogeneity, the prognostic value of TILs in gastric cancer (GC) is still controversial. Thus, this study aimed to investigate the association between the density of TILs and patients' outcomes in GC. METHODS: Patients with gastric adenocarcinoma who underwent curative intent gastrectomy were retrospectively investigated. The groups for analysis were determined on the basis of TIL intensity and percentage of CD3+ T-cell infiltration by immunohistochemical. Furthermore, Epstein-Barr virus (EBV), microsatellite instability (MSI), T-cell ratio of CD4 to CD8, and programmed death protein ligand 1 (PD-L1) status were evaluated. RESULTS: A total of 345 patients were enrolled: 124 patients with GCs (35.9%) were classified as the low-CD3+ TIL group, and 221 patients with GCs (64.1%) were classified as the high-CD3+ TIL group. Poorly differentiated histology (P = .014), EBV-positive status (P < .001), PD-L1-positive status (P = .001), and CD4 < CD8 (P < .001) were associated with high-CD3+ GC. There was no difference regarding MSI status, the degree of tumor invasion (pT), the presence of lymph node metastasis, and pTNM stage between low- and high-CD3+ groups. In survival analysis, the high-CD3+ group had better disease-free survival and overall survival rates than had the low-CD3+ group (P = .055 and P = .041, respectively). In the multivariate analysis, total gastrectomy, lymph node metastasis, advanced pT stage, and low CD3+ levels were independent factors related to worse survival. CONCLUSION: High CD3+ TILs levels were significantly associated with improved survival and could serve as prognostic biomarkers in GC. In addition, CD3+ T-cell infiltration was related to both EBV-positive and PD-L1-positive GC and may assist in the investigation of targets in immunotherapy.

Prognostic implications of tumor-infiltrating lymphocytes in association with programmed cell death ligand 1 expression in remnant gastric cancer.

Objective: Remnant gastric cancer (RGC) is usually associated with a worse prognosis. As they are less common and very heterogeneous tumors, new prognostic and reliable determinants are required to predict patients' clinical course for RGC. This study aimed to investigate the tumor-infiltrating lymphocytes (TILs) and programmed cell death ligand 1 (PD-L1) status as prognostic biomarkers in a cohort of patients with RGC to develop an immune-related score. Methods: Patients with gastric cancer (GC) who underwent curative intent gastrectomy were retrospectively investigated. RGC resections with histological diagnosis of gastric adenocarcinoma were enrolled in the study. The risk score based on immune parameters was developed using binary logistic regression analysis. RGCs were divided into high-risk (HR), intermediate-risk (IR), and low-risk (LR) groups based on their immune score. The markers (CD3+, CD4+/CD8+ T cells and PD-L1) were selected for their potential prognostic, therapeutic value, and evaluated by immunohistochemistry (IHC). Results: A total of 42 patients with RGC were enrolled in the study. The score based on immune parameters exhibited an accuracy of 79% [the area under the receiver operating characteristic curve (AUC)=0.79, 95% confidence interval (95% CI), 0.63-0.94, P=0.002], and the population was divided into 3 prognostic groups: 10 (23.8%) patients were classified as LR, 15 (35.7%) as IR, and 17 (40.5%) as HR groups. There were no differences in clinicopathological and surgical characteristics between the three groups. In survival analysis, HR and IR groups had worse disease-free survival and overall survival rates compared to the LR group. In the multivariate analysis, lymph node metastasis and the immune score risk groups were independent factors related to worse survival. Conclusions: A scoring system with immune-related markers was able to distinguish prognostic groups of RGC associated with survival. Accordingly, tumor-infiltrating immune lymphocytes and PD-L1 status may serve as a potential prognostic biomarker for patients with RGC.

Cytotoxic T-lymphocyte-associated protein 4 in gastric cancer: Prognosis and association with PD-L1 expression.

BACKGROUND: Cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is one of the most studied immune checkpoint in gastric cancer (GC). However, the prognostic role of CTLA-4 expression in GC is poorly described. This study aimed to evaluate CTLA-4 expression in GC and its impact on survival, including patients treated with standard platinum-based chemotherapy (CMT), and association with PD-L1 expression. METHODS: All GC patients who underwent D2-gastrectomy were investigated retrospectively. Tumor samples were examined for CTLA-4 and PD-L1 by immunohistochemistry. Tumor-infiltrating inflammatory cells, including CD4 + and CD8 + , were also examined. RESULTS: Among the 284 GC patients included, 159 (56%) were CTLA-4 positive and the remaining 125 (44%) were classified as negative. CTLA-4 positive GC was associated with increased inflammatory cell infiltration (p < 0.001), high CD8 + T cells (p = 0.016) and PD-L1 expression (p = 0.026). Considering GC referred for treatment, CTLA-4 negative patients who received CMT had a significant improvement in disease-free survival compared to untreated CLTA-4 negative (p = 0.028). In multivariate analysis, GC positive for both CTLA-4 and PD-L1 had a prognostic impact on survival. CONCLUSION: CTLA-4 positive was associated with PD-L1 expression and a high tumor-infiltrating CD8 + T cells. Accordingly, positivity for both CTLA-4 and PD-L1 was an independent factor associated to better survival in GC patients.