PAX—FKHR Fusion Genes and AChR-γ in Chinese Patients With Rhabdomyosarcoma: Diagnosis Using Formalin-Fixed Archival Tissues

Abstract

The majority of alveolar RMSs have t(2;13)(q35;q14) or (1:13)(p36;q14),which generate PAX3/7 -FKHR fusion genes. Here, the authors detected the PAX3/7-FKHR fusion transcripts in 17 formalin-fixed, paraffin-embedded RMSs and 26 other SRCTs using one-step RT-PCR. PAX3 -FKHR and PAX7-FKHR transcripts were positive in 4/8 and 2/8 cases of ARMS, respectively. 9 ERMSs and 26 other SRCTs were negative for PAX3/7-FKHR. In addition, AChR-γ and AChR-α mRNA were detected by semiquantitative duplex PCR in above cases and 3 normal muscles. 17 RMSs were found to have overexpression of AChR-γ, with an AChR-γ/-α ratio of ≥1; 3 cases of normal muscle had very weak AChR-γ expression, with an AChR- γ/-α ratio of <1. AChR-γ transcripts were not detectable in all 26 other SCRTs. The results demonstrated that detection of PAX3/7-FKHR fusion gene by one-step RT-PCR is useful in the diagnosis of RMS and that AChR-γ is overexpressed in Chinese RMS patients.