BACKGROUND: Intratumoral Fusobacterium nucleatum (Fn) infection is closely associated with poor prognosis in esophageal cancer (EC) due to its impact on the tumor microenvironment (TME). The tumor cell-intrinsic cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is critical for regulating immune cell activation in the TME. However, the link between intratumoral Fn infection and the activation of the cGAS-STING pathway in tumor cells, as well as its effects on EC progression, remains largely unknown. METHODS: In the present study, we investigated the impact of intratumoral Fn infection on the activation of the tumor cell-intrinsic cGAS-STING pathway and EC progression by analyzing our own EC cohort and performing in vitro experiments using co-cultures of EC-cell lines and Fn. RESULTS: The expression of tumor cell-intrinsic STING was significantly associated with worse prognosis in Fn-high EC patients. Exposure to Fn significantly activated the STING pathway in EC cells. RNA-seq analysis revealed that exposure to Fn markedly activated cytokine-chemokine-related signaling pathways and induced the expression of several cytokines and chemokines in STING-expressing EC cells. Among the differentially expressed cytokine and chemokine genes in EC cells co-cultured with Fn, analysis of TCGA datasets demonstrated that the expression of CCL20, CXCL10, and CSF2 may be associated with poor prognosis in EC patients. CONCLUSION: We revealed that the activation of the STING signaling pathway and the subsequent expression of cytokines and chemokines in EC cells induced by Fn infection may be closely associated with poor prognosis in EC patients.