To investigate the functions of PCDH9-AS1 in ESCC, a PCDH9-AS1 pcDNA3.1(+) vector was constructed (pcDNA3.1-PCDH9-AS1), resulting in the upregulation of PCDH9-AS1 (Figure 10A). Here, PCDH9 is linked to esophageal squamous cell carcinoma.