In this study, we show that CASC9 was significantly upregulated in ESCC tissues, and high CASC9 expression correlated with a deeper primary invasion depth, positive lymph node metastasis, and advanced TNM stage, suggesting that CASC9 can be a strong predictor for ESCC metastasis and prognosis. This evidence concerns the gene CASC9 and esophageal squamous cell carcinoma.