Genome-wide analyses have identified recurrent copy number alterations in chromosomal regions 11q (harboring CCND1), 3q (SOX2), 2q (NFE2L2), and 9p (CDKN2A), which represent trunk mutations—early clonal events crucial for the initiation and clonal evolution of ESCC (Liu et al., 2017). This evidence concerns the gene CCND1 and esophageal squamous cell carcinoma.