As expected, SNS-032 remarkably downregulated the levels of phospho-RNA Pol II (Ser 2), phospho-RNA Pol II (Ser 5), and phospho-RNA Pol II (Ser 7), but not the total RNA Pol II, CDK7, and CDK9 in tested cell line of ESCC (Fig. 1B). This evidence concerns the gene CDK7 and esophageal squamous cell carcinoma.