Spatial transcriptomics reveals immune remodeling in lymph nodes of gastric adenocarcinoma

Lymph node (LN) metastasis is a major determinant of prognosis in gastric cancer, yet the immune microenvironment of metastatic versus non-metastatic nodes remains incompletely defined. Spatial resolution of tumor-immune interactions may clarify mechanisms of immune escape associated with nodal progression. We performed compartment-resolved spatial transcriptomic profiling to characterize immune gene expression in gastric cancer LNs. Forty-seven formalin-fixed paraffin-embedded LNs from 13 patients with T2-T4, M0 gastric adenocarcinoma (N1-2: n = 7; N3: n = 6) were analyzed using the NanoString GeoMx Digital Spatial Profiler and an 84-gene immune pathways panel. Twenty-nine non-metastatic and 18 metastatic LNs were profiled. Regions of interest were segmented into tumor and immune compartments, yielding 65 spatially defined compartments. Differential expression was assessed across three comparisons: metastatic versus non-metastatic LNs; metastatic LNs from N1-2 versus N3 patients; and non-metastatic LNs from N1-2 versus N3 patients. Within the immune compartments, non-metastatic LNs showed higher expression of T-cell activation and checkpoint genes (CD3E, CD27, PDCD1, CTLA4), consistent with preserved immune surveillance. Metastatic LNs were enriched for WNT signaling and adhesion-related genes (CTNNB1, ITGAV) and epithelial markers (EPCAM), indicating tumor-driven immune remodeling. N3 metastatic LNs demonstrated increased ICOSLG, IL6, and IFNGR1 expression, suggesting chronic inflammatory activation and immune dysfunction. Notably, non-metastatic LNs from N3 patients upregulated antigen-presentation genes (CD74, HLA-DRB), consistent with early immune conditioning. No significant differences emerged in tumor compartments or pseudo-bulk analyses. Spatial transcriptomic profiling reveals nodal burden-associated immune remodeling, and identifies candidate biomarkers and therapeutic targets for precision immunotherapy in gastric cancer.