Abstract
Gastric cancer(GC) is the fifth most common type of cancer worldwide and ranks third in terms of cancer-related mortality. Immunotherapy has shown promising outcomes and greatly extended survival in individuals with advanced stomach cancer. To improve the immunotherapy response in patients with GC, it is necessary to discover new molecular targets. The associations among G protein subunit gamma transducin 1(GNGT1) expression, clinicopathological features, and prognosis were assessed via the UALCAN and Kaplan-Meier databases. The CIBERSORT algorithm in R software and single-sample gene set enrichment analysis(ssGSEA) were used to analyse the proportions of infiltrating immune cells in the high-expression group and the low-expression group.GNGT1 expression was substantially greater in GC tissues than in normal tissues, and patients with GC who had high GNGT1 expression had worse clinicopathological characteristics and survival outcomes. Immunohistochemistry(IHC) experiments on stomach adenocarcinoma(STAD) samples confirmed the aberrant expression of GNGT1 and its association with a poor prognosis. Subsequent investigations revealed substantial negative correlations between GNGT1 and tumour mutational burden(TMB), microsatellite instability(MSI), immune cell infiltration, immune cell gene marker expression and immunological checkpoint expression in patients with STAD.GNGT1 is a reliable biomarker in patients with GC that also has an immunomodulatory function in this disease and may accelerate GC development by suppressing the infiltration of T cells, dendritic cells, M1 macrophages and B cells.