Although several studies have associated MAGEs (including MAGEA2, MAGEA3, MAGEA6, and MAGEA9 expression) with pro-tumorigenic activities, such as p53 dysregulation, enhanced tumor proliferation, or the maintenance of cancer-stem-cell-like characteristics [97,98], their definitive functions are not still fully understood in the context of bladder cancer. This evidence concerns the gene MAGEA3 and urinary bladder cancer.