High expression of MAGE-A9 in tumor and stromal cells of non-small cell lung cancer was correlated with patient poor survival.

Melanoma associated antigen-A (MAGE-A) is an oncogene and correlated with tumor initiation and development. However the roles of MAGE-A9 in non-small cell lung cancer (NSCLC) are still unknown. We investigated MAGE-A9 mRNA expression in 18 tumor tissues of NSCLC by qRT-PCR and MAGE-A9 protein expression in 213 NSCLC samples of tissue arrays by immunohistochemical staining. We assessed the relationship between MAGE-A9 expression and clinical parameters. The results showed that the high expression of MAGE-A9 protein in NSCLC tumor cells were commonly present in squamous cell carcinomas (P = 0.030). It was also related to larger tumor diameter, lymph node metastasis and later stage grouping with TNM classification (all P < 0.05). Whereas the expression of MAGE-A9 in stromal cells was higher in squamous cell carcinomas as well. Cox regression univariate and multivariable analysis revealed that MAGE-A9 expression in tumor cells of NSCLC (P < 0.001) is an independent prognostic factor in five-year overall survival rate. We concluded that the molecular assessment of MAGEA9 could be considered to improve prognostic evaluation and to identify eligible patients for potential target therapy.