Melanoma antigen (MAGE)-A-derived peptides elicit a strong in vitro T-cell response against tumor cells. For determination of MAGE-A1, -2, -3, -4, -6, and -12 expression profile in invasive breast cancer, we developed a multiplex seminested reverse transcription-PCR-method. In total, 18 of 67 (27%) tumors were positive for at least one of these MAGE transcripts, and the expression pattern was heterogeneous: MAGE-A1 was positive in 4 of 67 (6%), MAGE-A2 in 13 of 67 (19%), MAGE-A3 in 7 of 67 (10%), MAGE-A4 in 9 of 67 (13%), MAGE-A6 in 10 of 67 (15%), and MAGE-A12 in 6 of 67 (9%) patients. The MAGE-A transcripts were more frequently expressed in ductal breast carcinomas compared with other histomorphological types. We observed a preferential expression of MAGE-A in patients at a higher risk of recurrence: those harboring tumors with high levels of the protease urokinase-type plasminogen activator and its inhibitor plasminogen activator inhibitor 1, high score of the Ki-67 proliferation antigen, and lesser degree of differentiation. Our findings suggests a potential involvement of MAGE-A in tumor progression, with potential implications for active immunotherapy.
