TFE3 and neoplasm: TFE3 IHC was believed to have a high specificity and sensitivity for diagnosis,10 but its predictive value was found to be only 12% in a recent study by Klatte et al.11 Reverse transcription–polymerase chain reaction (PCR) and cytogenetic karyotypic analysis are tools that can be used to ascertain specific types of genetic changes in tumor cells.12 However, fresh tumor tissues are not always available, and reverse transcriptase–PCR occasionally fails to detect the translocation due to the instability and rapid degradation of RNA in a formalin-fixed, paraffin-embedded (FFPE) block.