High expression of MAGE-A9 is associated with unfavorable survival in esophageal squamous cell carcinoma

Melanoma-associated antigens (MAGEs) are a group of well-characterized members of the cancer/testis antigen family, which are expressed in a variety of malignant tumors. MAGE-A9, a subfamily of MAGE-As, has been studied in a number of types of cancer and have been associated with unfavorable survival outcome. However, the expression of MAGE-A9 in human esophageal squamous cell carcinoma (ESCC) and association of MAGE-A9 with the clinicopathological characteristics of ESCC, particularly prognostic characteristics, remains unknown. The present study aimed at determining the expression level of MAGE-A9 and at evaluating its clinical significance in human ESCC. Quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC) analyses were performed to characterize the expression of MAGE-A9 in ESCC tissues. Kaplan-Meier estimator survival and Coxs regression analyses were used to evaluate the prognosis of 103 patients with ESCC. The results of qPCR and IHC analysis revealed that the expression of MAGE-A9 was significantly increased in ESCC tissues, compared with that in healthy tissues. Furthermore, the expression level of MAGE-A9 protein in ESCC was significantly associated with the pathological grade (P=0.008), tumor size (P=0.027) and lymph node metastasis (P=0.009). Multivariate analysis using Coxs regression model identified that the expression level of MAGE-A9 and lymph node metastasis were independent prognostic factors for the overall survival rate of patients with ESCC (P=0.006 and P=0.001, respectively). The results of the present study are, to the best of our knowledge, the first to indicate that MAGE-A9 expression is a valuable prognostic biomarker for ESCC and that it may serve as a targeted therapy in the treatment of ESCC. Increased expression of MAGE-A9 indicated an unfavorable survival outcome in patients with ESCC.