In clinical samples, seven (MCM2, CDK1, MCM7, MCM5, MCM6, LIG1, and MCM3) of these eight proteins were found to be significantly overexpressed in ESCC patients, with MCM2 and CDK1 as the top-2 most upregulated proteins (Figure 4G). This evidence concerns the gene MCM2 and esophageal squamous cell carcinoma.