RT-PCR法检测EWS-FLI1融合基因诊断尤文肉瘤/外周原始神经外胚层瘤

Diagnosis of Ewing's sarcoma/peripheral primitive neuroectodermal tumor by RT-PCR amplification of EWS-FLIl fusion gene in paraffin-embedded tissues

目的探讨尤文肉瘤/外周原始神经外胚层瘤(EWS/pPNET)石蜡包埋组织中EWS-FLI1融合基因表达的临床病理意义。方法采用免疫组化对1例纵隔尤文肉瘤/外周原始神经外胚层瘤进行观察,应用反转录-聚合酶链反应(RT-PCR)检测融合基因EWS-FLI1的表达。结果肿瘤由小圆细胞、卵圆形细胞及短梭形细胞构成,巢状、片状或列兵样排列,间质显著增生,未见典型菊形团结构。免疫组化显示CK、EMA和CD99弥漫强(+)。RT-PCR检测出EWS-FLIl融合基因的表达。结论EWS/pPNET与促结缔组织增生性小圆细胞肿瘤(DSRCT)具有重叠的形态学和免疫组化特点,石蜡包埋组织中检测EWS-FLI1融合基因的表达可作为诊断EWS/pPNET的可靠指标。

Objective To investigate the significance of expression of EWS-FLI1 fusion transcript in paraffin-embedded tissues of Ewing＇s sarcoma/peripheral primitive neuroectodennal tumor （EWS/pPNET） by reverse transcription polymerase chain reaction （RT-PCR）. Methods The immnophenotype of EWS/pPNET was studied by SP method using a panel of antihodis. EWS-FLI1 fusion transcript was detected by RT-PCR. Results Histologically, the tumor was composed of small, round, ovoid to spindled cells arranged in nests, sheets and lines, embedded in a desmoplastic stroma. Rosette was absent. study revealed diffuse and strong positive for CK, EMA and CD99. EWS-FLII fusion transcript was detected. Conclusion EWS/ pPNEF and DSRCT exhibit similar features in morphology and immunohistochemistry. Detection of EWS-FLI1 fusion transcript in paraffin-embedded tissues of EWS/pPNET by RT-PCR is a reliable marker for molecular diagnosis.