Emerging studies have found that long noncoding RNA cancer susceptibility candidate 9 (CASC9) is highly expressed in various cancers, such as esophageal squamous cell carcinoma, nasopharyngeal carcinoma and hepatocellular carcinoma, implying a crucial carcinogenic effect of this lncRNA13–19. Here, CASC9 is linked to esophageal squamous cell carcinoma.