Breast cancers are known to frequently (over)express several well-characterized tumor-associated antigens (TAAs) such as carcinoembryonic antigen, MUC-1, Her-2/neu, and cancer/testis antigens such as NY-ESO-1, SSX-2, and members of the MAGE family.
For defined tumor types, expression of at least one of the SSX family members was most frequently observed in head and neck cancer (75%), followed by ovarian cancer (50%), malignant melanoma (43%), lymphoma (36%), colorectal cancer (27%) and breast cancer (23%), while leukemias and the few cases of leiomyosarcomas, seminomas and thyroid cancers were found not to express any SSX gene.