Indications with ≥20% prevalence of MAGE-A4 positivity were synovial sarcoma (70%), myxoid/round cell liposarcoma (40%), urothelial cancer (32%), esophagogastric junction cancer (26%), ovarian cancer (24%), HNSCC (22%), and esophageal cancer (21%). This evidence concerns the gene MAGEA4 and round cell liposarcoma.