Glucose transporter 1 (GLUT1) is a sensitive immunohistochemical marker for perineural cells and certain mesenchymal neoplasms, including chordoma, desmoplastic small round cell tumor, desmoid-type fibromatosis, epithelioid sarcoma, gastrointestinal stromal tumor, myoepithelioma, schwannoma, and undifferentiated pleomorphic sarcoma. The gene discussed is SLC2A1; the disease is desmoid tumor.