The median serum levels of IgG and IgA for P. gingivalis were significantly higher in ESCC patients than in non-ESCC controls (150.69 EU vs. 109.13 EU, P < 0.001 for IgG; 33.16 EU vs. 19.14 EU, P < 0.01 for IgA). This evidence concerns the gene CD79A and esophageal squamous cell carcinoma.