PCAT6 and esophageal squamous cell carcinoma: To investigate the biological role of PCAT6 in ESCC tumorigenesis, we first knocked down the expression level of PCAT6 using siRNAs targeting PCAT6. As shown in Figure 2A, the expression of PCAT6 in Eca-109 and Kyse-30 cells was significantly decreased after transfection with PCAT6 siRNAs.