A Swedish case–control study showed serum CagA antibodies and gastric atrophy were associated with an increased risk for ESCC (odds ratio [OR] = 2.1, 95% confidence interval [CI] = 1.1 to 4.0, and OR = 4.3, 95% CI = 1.9 to 9.6, respectively) [31]. This evidence concerns the gene S100A8 and esophageal squamous cell carcinoma.