Identification of MAGEA12 as a prognostic outlier gene in gastric cancers

Melanoma antigen (MAGE) family genes are frequently over-expressed in a subset population of multiple cancers, and serve as idea therapeutic targets; however, their distribution pattern in gastric cancers has not yet been evaluated. In this study, we first performed a cancer outlier profile analysis (COPA) on a series of public gene expression datasets of gastric cancer, and identified MAGEA12 showing a significant outlier expression model reproducibly. We further in silico validated that MAGEA12 outlier over-expression were associated with poor clinical outcome using six microarray datasets from GEO database. We then experimentally detected the MAGEA12 expression in an independent cohort of gastric cancer samples by immunohistochemistry, and showed that over-expression of MAGEA12 in a subset of cancers was associated with later stage and reduced survival; furthermore, MAGEA12 was an independent prognostic factor in an outlier manner. Our results indicate that MAGEA12 is a novel prognostic outlier gene in gastric cancers and patterns of MAGE expression may inform individualized targeted immunotherapies.