横纹肌肉瘤中融合基因PAX3／PAX7-FKHR表达和染色体遗传变异

Expression of fusion gene PAX3/PAX7-FKHR and chromosomal aberration in rhabdomyosarcoma

目的 研究融合基因PAX3／PAX7-FKHR与胚胎型横纹肌肉瘤（embryonal rhabdomyosarcoma，ERMS）和腺胞型横纹肌肉瘤（alveolar rhabdomyosareonm，ARMS）遗传学改变的特征。方法 用一步法逆转录．聚合酶链反应（reverse transcriptase-polymerse chain reaction，RT-PCR）技术对16例横纹肌肉瘤（rhabdomyosarcoma，RMS）和16例肉瘤周围正常组织的PAX3／PAX7-FKHR融合基因mRNA的表达进行了检测；应用比较基因组杂交（comparative genomic hybridization，CGH）技术检测16例RMS的不平衡即DNA的丢失或扩增。结果 7例ARMS中有5例PAX3／PAX7-FKHR融合基因mRNA表达（3例PAX3-FKHR融合基因表达，2例PAX7-FKHR融合基因表达）；9例ERMS及16例对照组肿瘤组织中无PAX3／PAX7-FKHR融合基因表达。每例RMS细胞染色体均有不同程度的变异，RMS常见扩增的染色体是1p36（69％），5q32（56％），8q21（63％），13q14（69％），19q（63％），20q（56％）；常见缺失的染色体是3p21-pter（56％），9p23．pter（50％），10q（69％），16／16q24（56％）。结论 一步法RT-PCR技术检测染色体易位融合基因为临床RMS疑难病例的诊断和研究提供了有效技术手段；RMS特异性染色体易位融合基因的表达是其分子诊断的可靠指标。

Objective To detect the PAX3/PAX7-FKHR fusion transcripts to identify genetic alteration in embryonal rhabdomyosareoma （EBMS） 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 EBMS） 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 EBMS and Control tumors. There＇re different chromosome variations for each RMS, chromosome amplification was frequently seen in 1 p36 （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.