Consistent with this notion, we recently found significantly higher frequency of CT mRNA expression in estrogen receptor (ER) and progesterone receptor (PR) negative breast cancer cell lines and primary breast cancers, including MAGE-A3, MAGE-A6, NY-ESO-1, MAGE-A12, LAGE-1, CSAG2 etc [12]. This evidence concerns the gene CSAG2 and breast cancer.