WT1 and undifferentiated pleomorphic sarcoma: Nakatsuka et al. [28] reported that 70% of 32 soft tissue sarcomas showed positivity for WT1 immunostaining and that 100% of rhabdomyosarcomas, malignant fibrous histiocytomas, MPNSTs, and clear cell sarcomas showed positive staining for WT1 when using monoclonal (6 F-H2) antibody.