Abstract 2513: MAGE-A3, MAGE-A4, and PD-L1 protein show co-expression in colon, lung and bladder cancer

Abstract

Abstract PD-L1 programmed death ligand 1/CD274 has been shown to be an excellent immune therapy target for many tumors. Currently, studies have shown PD-L1in combination with other immune therapy targets can improve patient outcomes generating the need for new targets. One candidate is the cancer testis antigen Melanoma Antigen Gene Family (MAGE-A) because these genes have limited expression in normal tissues and high expression in cancer. Clinical trials have already begun targeting MAGE-A3 and MAGE-A4 proteins in multiple tumor types. Protein assessment of individual MAGE-A family members has been challenging due to sequence homology as high as ninety-five percent between members. Previously, with the use of CytoSections two highly specific antibodies for immunohistochemistry to MAGE-A3 (clone OTI1H1) and MAGE-A4 (clone OTI2C1) were found. In this study, the MAGE-A3 and MAGE-A4 antibodies were screened with PD-L1 on colon, lung, and bladder cancers. Results show detection of both MAGE-A3 and MAGE-A4 in 25% of colon; 30% of lung; and 20% of bladder cancers. More than 70% of the lung and bladder cancers were positive for MAGE-A4 but only six of twenty-four colon cancers were positive for MAGE-A4. The results show 60 percent of the positive for MAGEA3 or MAGEA4 in colon, lung, and bladder cancers were also positive for PD-L1. This study suggests that MAGE-A3 and MAGE-A4 have tumor specific expression patterns and a potential to be a co-immunotherapy target with PD-L1. Citation Format: Rachel Gonzalez, YiChen Guo, Jina Yom, Bailey Gilmore, Eden Zewdu, Xi-Andy Han, Dehe Kong, Tianli Qu, Qi Ren, Xiaomin Hu, Ranran Zhang, Zhaohui Wu, Alex Strom, Xuan Liu, Wei Fu. MAGE-A3, MAGE-A4, and PD-L1 protein show co-expression in colon, lung and bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2513.