Those neoplasms usually labeled for CK7, CA9, and GATA3, not expressed in TFE3-rearranged renal cell carcinomas, which are instead commonly positive for cathepsin K. Either TFE3-rearranged renal cell carcinomas or TFEB-rearranged renal cell carcinomas demonstrating papillary architecture can be confused with papillary renal cell carcinoma. This evidence concerns the gene CTSK and papillary renal cell carcinoma.