Objective: To detect the PAX3/PAX7-FKHR fusion transcripts to identify genetic alteration in embryonal rhabdomyosarcoma (ERMS) and alveolar rhabdomyosarcoma (ARMS) tissues.
Methods: One-step reverse transcription- polymerase chain reaction (RT-PCR) were used to detect the expression of the PAX3/PAX7-FKHR fusion transcrips in 16 cases of rhabdomyosarcoma (7 cases of ARMS, 9 cases of ERMS) and 16 specimens were compared to the surrounding normal tissue. Comparative genomic hybridization (CGH) was employed to detect the genomic imbalance (DNA loss or amplification) in 16 RMS cases.
Results: PAX3-FKHR fusion transcripts were positive in 3/7 and PAX 7-FKHR fusion transcripts were positive in 2/7 of ARMS patients, respectively, and were all negative in ERMS and Control tumors. There were different chromosome variations for each RMS, chromosome amplification was frequently seen in 1p36 (69%), 5q32 (56%), 8q21 (63%), 13q14 (69%), 19q (63%), 20q (56%). Chromosome loss was frequently seen in 3p21-pter (56%), 9p23-pter (50%), 10q (69%), 16/16q24 (56%).
Conclusion: One-step RT-PCR assay for detection specific fusion gene provides a useful tool for confirmation of the diagnosis of RMS in diagnostically difficult cases and in retrospective studies. Chimeric gene transcript resulting from specific chromosomal translocations is a reliable index for the molecular diagnosis of RMS.