Serum IgG titer findings for Fusobacterium nucleatum associated with clinical outcome following surgery in patients with esophageal squamous cell carcinoma

Fusobacterium nucleatum (Fn) is known as an etiological factor related to periodontitis. However, recent reports have shown that it also functions as an oncogenic pathogen and is associated with progression of various cancers as well as poor prognosis of esophageal squamous cell carcinoma (ESCC) patients. The present study was conducted to examine the correlations of serum IgG antibody titer level against Fn (IgG-Fn) with clinicopathological characteristics, oral conditions, and survival outcomes in 305 patients who underwent an esophagectomy procedure for ESCC. The results revealed that 40.7% of the patients tested positive for IgG-Fn, and those in the positive group had significantly lower rates of overall survival (OS) and cancer-specific survival (CSS) as compared to patients who tested negative (OS; p = 0.01, CSS; p = 0.02). Multivariate analysis showed IgG-Fn positivity as an independent predictor of CSS (hazard ratio, 1.96; 95% CI, 1.32-2.90; p < 0.001). Moreover, among patients who were diagnosed with stage II-IV and underwent neoadjuvant therapy (NAT), those in the IgG-Fn-positive group showed higher pathological progression and greater incidence of inadequate response to NAT as compared to the IgG-Fn-negative group (odds ratio 0.48, 95% CI 0.24-0.92; p = 0.04). The present findings indicate that IgG-Fn can serve as a marker indicating poor tumor response to NAT in advanced ESCC cases.