AFP and esophageal squamous cell carcinoma: Abnormal circRNA expressions were correlated with TNM stage (chi2 = 61.64, p = 0.000), lymph node metastasis (chi2 = 35.06, p = 0.000), distant metastasis (chi2 = 16.40, p = 0.012), and Cyfra21‐1 level (chi2 = 18.23, p = 0.006) in ESCC patients, but not significant in age, gender, tumor size, smoking status, as well as CEA and AFP levels, all with p > 0.05 (Table 5).