It has also been reported to occur in highly aggressive sarcomas such as undifferentiated pleomorphic sarcoma (UPS) [22], myxofibrosarcoma (MFS) [23], and malignant peripheral sheath tumor (MPNST) [24]; however, the number of reports and cases is very small, and the clinical significance of NY-ESO-1 and MAGE-A4 expression has not been investigated [17,25,26]. The gene discussed is MAGEA4; the disease is malignant peripheral nerve sheath tumor.