PAEP and synovial sarcoma: Glycodelin is highly expressed in all biphasic synovial sarcomas (11/11) with epithelial glandular differentiation but slightly expressed in monophasic sarcomas (1/7) (48), regarding the monoclonal origin of synovial sarcomas, which hints that glycodelin may play a role in the malignant transformation in synovial sarcomas (Table 5).