Immunohistochemically, the tumor cells were positive for transcription factor E3 (TFE3) (Fig. 2F) (which confirmed the histological diagnosis of ASPS), myogenic determination factor 1 (MyoD1) (Fig. 2E), and (focal) PAS-D (Fig. 2C), with negativity for desmin and synaptophysin. The gene discussed is TFE3; the disease is alveolar soft part sarcoma.