Many tumor antigens have been defined in terms of multiple solid tumors: MART-1/Melan-A, gp100, carcinoembryonic antigen (CEA), HER-2, mucins (i.e., MUC-1), prostate-specific antigen (PSA), and prostatic acid phosphatase (PAP) are just a short list. Some immune-based therapies targeting these tumor antigens are in phase III trials assessing whether immunizing against these antigens affects overall survival. In gastric cancer, some tumor antigens such as MAGE-A3, NY-ESO-1, and WT-1 have been reported to be expressed in substantial proportion of cases. They have the potential to be the targeting molecules for immunotherapy in the future. In this study, we aim to explore the expression levels of the four tumor markers (MAGE-A3, NY-ESO-1, WT-1 and PRAME) in gastric cancers of Korean patients and to examine the correlations of the expression levels of the four markers to clinic-patholoical factors.