MAGEA4 and synovial sarcoma: The expression of MAGE-A4 is notable in head and neck squamous cell carcinoma (HNSCC), synovial sarcoma (SS), Reed–Sternberg cells, serous ovarian neoplasms, myxoid/round cell liposarcoma (MRCLS), NSCLC, urothelial cancer, melanoma and gastroesophageal cancer [34,35,36,37,38,39].