An antibody against the C-terminus of TFE3 has been identified as a highly specific and sensitive marker of ASPS.31,32 Tanaka et al. described a strong expression of GPNMB, a transcriptional target of TFE transcription factors, upregulated by ASPL-TFE3 expression playing an important role in neoplastic invasion, metastases and endothelial migration in the intravascular lesions of ASPS.33 The gene discussed is GPNMB; the disease is alveolar soft part sarcoma.