STAT6 and sarcomatoid mesothelioma: All dedifferentiated liposarcomas (0/5 pos), deep benign fibrous histiocytomas (0/5 pos), sarcomatoid mesotheliomas (0/5 pos), low grade fibromyxoid sarcomas (0/7 pos), schwannomas (0/5 pos), malignant peripheral nerve sheath tumors (0/4 pos), gasto-intestinal stroma cell tumors (0/5 pos), synovial sarcomas (0/5 pos) and leiomyomas (0/6 pos) showed no nuclear staining for STAT6.