CDKN2A and esophageal squamous cell carcinoma: In previous studies, it was considered that the expression levels of p53 (1–3), p21waf1(4), molecular immunology borstel-1 (MIB-1) (2,5), p16INK4A(6), cyclin D1 (2,7,8), E-cadherin (8), Bcl-2 (1), tumor necrosis factor (TNF)-α (9), nuclear factor (NF)-κB (10), transforming growth factor (TGF)-β (11), matrix metalloproteinase (MMP)-7 (12), cyclooxygenase (COX)-2 (13,14), epidermal growth factor receptor (EGFR) (15) and hypoxia-inducible factor (HIF)-1α (16) may be used as prognostic factors for ESCC.