MAGEA9 and neoplasm: CT83 with the MAGE family (MAGE‐A1, MAGE‐A3, MAGEH1, MAGE‐A9, MAGE‐C1/CT7, and MAGE‐C2/CT10) and NY‐ESO‐1, the most prevalently expressed antigens in spontaneous humoral to mediate T cell responses, has been described in tumor patients.24, 25, 26, 27, 28 Shida et al14 reported that CT83 expression was observed in gastric cancer, while the frequency of CT83 expression (81.6%) was higher than that of the MAGE‐A1 (34.7%), MAGE‐A3 (44.9%), and NY‐ESO‐1(16.3%).