ACTB and esophageal squamous cell carcinoma: In the 50 cases of esophageal squamous cell carcinoma, the ratio of ADAM17 mRNA expression to that of β-actin was increased to 0.937±0.241 (Table I), compared with the ratio of expressions in normal esophageal mucosa, which was 0.225 ± 0.077 (P<0.01).