CASC9 and esophageal squamous cell carcinoma: We next analyzed the relationship between ESCCAL-1 expression and clinical characteristics of ESCC patients, and found that high expression of ESCCAL-1 was significantly correlated with poor tumor differentiation (p = 0.007) and slightly associated with advanced tumor stage (p = 0.072), but there is no positive correlation with age or gender (Supplementary Table 2).