Objective To screen novel immune-related genes in gastric cancer through bioinformatics approaches, conduct preliminary experimental validation in gastric cancer cells, and elucidate the role of SLC7A7 in the immune microenvironment of gastric cancer via multi-omics integration.

Methods Gastric cancer datasets were obtained from the GEO database, and differentially expressed genes were identified. Protein-protein interaction networks were analyzed using STRING software, while gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed using Metascape. The correlation between gene expression and clinical characteristics was validated using TCGA data. The expression of SLC7A7 across various cancers was analyzed using TIMER2.0. Survival analysis was conducted using Kaplan-Meier Plotter. The expression level of SLC7A7 in gastric cancer cell lines was validated by reverse transcription quantitative polymerase chain reaction (RT-qPCR).

Results SLC7A7 was highly expressed in gastric cancer and various other cancers, and was associated withpoor prognosis. SLC7A7 may exert its effects through the PI3K-Akt and AMPK signaling pathways. SLC7A7 was negatively correlated with memory B cells, naive B cells, monocytes and activated NK cells, while positively correlated with activated CD4⁺ memory Tcells, γδ T cells, resting NK cells, unpolarized macrophages and M1/M2 macrophages. RT-qPCR results demonstrated high expression of SLC7A7 in five gastric cancer cell lines (HGC-27, NCI-N87, MKN-45, MKN-74 and AGS).

Conclusion SLC7A7 is highly expressed in gastric cancer cell lines and is associated with tumor immune infiltration and poor prognosis in gastric cancer patients.