MAGEA4 and ovarian cancer: The MAGE‐A4, MAGE‐A1, MAGE‐A3, OY‐TES‐1, and MAGE‐C expressions were shared in 95% of ovarian cancer cases, while the expression levels of SP17, GAGE, NY‐ESO‐1, and XAGE‐1D were found to be closely associated with an increased risk of tumor progression.