〔Abstract〕 ObjectiveTo investigate the regulatory role of Porphyromonas gingivalis (Pg) infection on the EGFR/GSK3β signaling axis, and its impact on epithelial-mesenchymal transition (EMT) and cetuximab (Ctx) resistance in esophageal squamous cell carcinoma (ESCC). Methods Single cell RNA sequencing was employed to perform differential analysis of cellular subpopulations, identifying differentially expressed genes in ESCC tissues infected and non-infected with Pg. IHC was conducted to assess the expression of Pg and epidermal growth factor receptor (EGFR) in ESCC tissues. Western blot, RT-PCR, and IF staining were performed to evaluate EGFR expression in Pg infected ESCC cell lines KYSE70 and TE1. ESCC cells were treated with Pg and EGFR inhibitor Ctx, and divided into four groups: negative control (NC) group, P. gingivalis group, Ctx group, Pg+Ctx group. Cell proliferation, migration and invasion abilities were evaluated using CCK-8, plate cloning, wound healing and Transwell assay. Western blot analysis was performed to detect the expression of EMT and EGFR/GSK3β signaling pathway-associated proteins and their phosphorylation levels. Transforming growth factor-β1 (TGF-β1) was used to induce EMT in ESCC cells, promoting a transition from the epithelial phenotype to mesenchymal-like phenotype. The differential effects of Ctx on these two phenotypic states were subsequently compared. ResultsEpithelial cells were predominantly enriched in Pg-positive tissues, and Pg infection promoted the upregulation of EGFR expression in ESCC cells. Compared to the NC group, Pg treatment significantly enhanced the proliferation, invasion and migration capabilities of ESCC cells, and also increased chemoresistance to Ctx and reduced its antitumor efficacy. Pg induced EMT in ESCC cells via the EGFR/GSK3β signaling pathway. Notably, Ctx exhibited markedly weaker inhibitory effects on mesenchymal-like cells compared to epithelial ESCC cells. Conclusion Pg promotes ESCC cells proliferation, invasion and migration by regulating EMT through the EGFR/GSK3β signaling pathway, and enhances chemoresistance to Ctx.