Clinical significance of melanoma antigen-encoding gene-1 (MAGE-1) expression and its correlation with poor prognosis in differentiated advanced gastric cancer.

Melanoma antigen-encoding gene-1 (MAGE-1), a cancer/testis antigen, has been reported to be expressed in various types of cancer. We investigated the clinicopathological features and prognostic significance of MAGE-1 expression in advanced gastric cancer (AGC). Immunohistochemical staining for MAGE-1 was performed on surgical specimens obtained from 135 patients with AGC. Positive expression of MAGE-1 detected in cytoplasm was observed in 44 of 135 cases (32.6%) in primary tumors and 26 of 96 (27.1%) in lymph node metastases. In noncancerous gastric tissues, apparent MAGE-1 expression was not detected. MAGE-1 in primary tumor was correlated with advanced age (P < 0.001), macroscopic infiltrated type (P = 0.035), and presence of vascular invasion (P = 0.027). The 5-year cancer-specific survival rates of AGC patients with positive MAGE-1 expression were significantly lower than those of patients with negative MAGE-1 (positive: 31.6%, negative: 57.6%, P = 0.038). On multivariate analysis, MAGE-1 expression was not an independent prognostic predictor of AGC (P = 0.064). In differentiated AGC patients, MAGE-1 expression was correlated with advanced age (P = 0.003), macroscopic infiltrated type (P = 0.009), and presence of lymph node metastasis (P = 0.033). The cancer-specific survival rates of differentiated AGC patients with positive MAGE-1 were significantly lower than those of patients with negative MAGE-1 (P = 0.003). Positive MAGE-1 expression was an independent prognostic factor of differentiated AGC patients on multivariate analysis (P = 0.031). These findings suggest that MAGE-1 protein expression can serve as a predictive marker of poor prognosis in differentiated AGC patients.