Prognostic value of PAX9 in patients with esophageal squamous cell carcinoma and its prediction value to radiation sensitivity

Abnormal paired box 9 (PAX9) expression is associated with tumorigenesis, cancer development, invasion and metastasis. The present study investigated the prognostic significance of PAX9 in esophageal squamous cell carcinoma (ESCC) and its role in predicting radiation sensitivity. A total of 52.8% (121/229) ESCC tissues were positive for PAX9. The 1-, 3- and 5-year disease-free survival (DFS) rates were 72.2, 35.2 and 5.6%, respectively, and the overall survival (OS) rates were and 86.1, 44.4, and 23.1%, respectively, in PAX9-positive tumors. In PAX9-negative tumors, the one-, three- and five-year DFS rates were 76.9, 47.9 and 24.0%, and the OS rates were 90.9, 57.9 and 38.8%, respectively. Univariate analysis revealed that PAX9, differentiation, T stage, lymph node metastasis, and tumor-node-metastasis stage were associated with OS. Multivariate analysis of DFS and OS revealed that the hazard ratios for PAX9 were 0.624 (95% CI: 0.472–0.869, P=0.004) and 0.673 (95% CI: 0.491–0.922, P=0.014), respectively. Patients that received adjuvant therapy exhibited significant differences in the 5-year DFS (P<0.001) and OS (P<0.001). PAX9-positive ESCC patients who received post-surgery radiotherapy had a significantly greater 5-year DFS (P=0.011) and OS (P=0.009) than patients who received surgery only. Thus, PAX9 may be an independent prognostic factor for the surgical treatment of ESCC and a possible predictor of radiation sensitivity.