Thanawat Suwatthanarak, Chawisa Nampoolsuksan, Pariyada Tanjak, Kullanist Thanormjit, Onchira Acharayothin, Amphun Chaiboonchoe, Tharathorn Suwatthanarak, Manop Pithukpakorn, Wipapat Vicki Chalermwai, Jirawat Swangsri, Asada Methasate, Vitoon Chinswangwatanakul, Thammawat Parakonthun
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.