Importantly, copy-number analyses verified the deletion of CDKN2A and immunohischemistry (IHC) staining in tissue-microarray containing 36 atypical hyperplasia tissues and 72 of ESCC tumors confirmed the loss of expression of p16INK4A (Figure 2D-2F), indicating that CDKN2A depletion may be a potential biomarker for early detection of ESCC. Here, CDKN2A is linked to esophageal squamous cell carcinoma.