The area under the curve (AUC) values of p27 protein in ESAC, ESCC, GC and CRC were 0.98 (95% CI: 0.66–1, P = 0.0001; sensitivity: 0.8; specificity: 1; Figure 3E), 0.79 (95% CI: 0.66–0.89, P = 0.0001; sensitivity: 0.69; specificity: 0.77; Figure 3F), 0.94 (CI: 0.86–0.99, P = 0.0001; sensitivity: 0.78; specificity: 1; Figure 3G) and 0.79 (95% CI: 0.67–0.88, P = 0.0001; sensitivity: 0.6; specificity: 0.9; Figure 3H), respectively. The gene discussed is CDKN1B; the disease is esophageal squamous cell carcinoma.