Alterations of these genes, such as inactivation of RB1 and CDKN2A and amplification of CCND1, CDK6, and MDM2 have been well documented in ESCC (Huang et al., 2007; Baba et al., 2014; Jiang et al., 2020). This evidence concerns the gene CDK6 and esophageal squamous cell carcinoma.