The potential anti-ESCC mechanism following DIM+DFMO treatment was that through downregulation of the Cell Cycle and DNA Replication associated proteins (MCM2/3/5/6/7, CDK1 and LIG1), the hyperactive activities of these signaling pathways were suppressed and lead to the inhibition of tumor proliferation in ESCC patients (Figure 5I). This evidence concerns the gene LIG1 and esophageal squamous cell carcinoma.