Immunostaining for NY-ESO-1, MAGE-A4, and Ki67 was performed using pathological specimens harvested from 10 undifferentiated pleomorphic sarcoma (UPS), nine myxofibrosarcoma (MFS), and three malignant peripheral nerve sheath tumor (MPNST) patients treated at our hospital. This evidence concerns the gene MKI67 and myxofibrosarcoma.