In addition to TFE3, cathepsin K also shows consistent diffuse positivity in ASPS, which is helpful for differential diagnosis against other tumors such as renal cell carcinoma, ASPCR1-TFE3 translocation renal cell carcinoma, adrenal cortex carcinoma, and paraganglioma (46, 47). The gene discussed is TFE3; the disease is renal cell carcinoma.