粘液样/圆细胞型脂肪肉瘤石蜡包埋组织中FUS-CHOP融合基因的检测

Detection of FUS-CHOP fusion gene transcript in paraffin-embedded myxiod/round cell liposarcoma

目的:探讨逆转录-聚合酶链反应(RT-PCR)方法用于检测甲醛固定、石蜡包埋组织中FUS-CHOP融合基因的可行性及其对粘液样/圆细胞型脂肪肉瘤诊断的价值。方法:收集粘液样/圆细胞型脂肪肉瘤石蜡包埋组织标本25例,以其它类型脂肪肉瘤(包括分化良好型、去分化型、多形型),滑膜肉瘤,低度恶性纤维肉瘤,恶性纤维组织细胞瘤,粘液脂肪瘤,脂肪母细胞瘤,神经鞘瘤伴粘液变性和粘液软骨肉瘤作为阴性对照,共18例。所有标本均经过甲醛固定、石蜡包埋。用嵌套式RT-PCR的方法检测FUS-CHOP融合基因mRNA并经测序证实,以β-actin基因作为内对照检测mRNA质量。结果:43例标本中,30例可检出β-actin,阳性率为69.8%,其中粘液样/圆细胞型脂肪肉瘤标本β-actin阳性18例(72%),对照组β-actin阳性12例(66.7%)。25例粘液/圆细胞型脂肪肉瘤中15例检出Ⅱ型FUS-CHOP融合基因表达,阳性率60%(15/25),去除β-actin阴性病例的阳性率为77.8%(14/18)。其中1例β-actin阴性表达而检出FUS-CHOP融合基因。对照组18例标本均未检出FUS-CHOP融合基因。结论:FUS-CHOP融合基因在粘液样/圆细胞型脂肪肉中呈特异性表达,可作为该肿瘤的特异性标志物用于诊断。嵌套式RT-PCR的方法可用于甲醛固定、石蜡包埋组织中FUS-CHOP mRNA的检测。

Objective ：To investigate the feasibility of detecting FUS - CHOP fusion gene transcript in paraffin - embedded tissue and its diagnostic value for myxiod/round cell liposarcoma（MRCL）. Methods：Twenty - four formalin - fixed, paraffin - embedded MRCLs and eighteen control cases （the other types liposarcomas, synovial sarcoma, low potential malignancy fibrosarcoma, malignant fibrous histiocytoma, myxolipoma, lipoblastoma , neurinoma , myxochondrosarcoma） retrieved from the archival files were studied . Nested reverse transcription - polymerase chain reaction（ RT- PCR） technique was employed to detect the FUS - CHOP mRNA expression, followed by DNA sequencing confirmation of the PCR product. β - actin gene was used to assess the quality of the mRNA templates. Results： β -actin mRNA was detected in 30 of 43 tumor cases（69.8% ）, including 18 MRCLs（18/25, 72% ） and 12 nega- tive control （ 12/18,66.7% ）. Type Ⅱ FUS - CHOP fusion transcript was successfully detected in 15 out of 25 （60%） MRCLs. All 18 negative control cases were negative for the FUS -CHOP fusion gene transcripts. Conclusion：FUS - CHOP is considered a specific molecular and genetic hallmark for MRCLs and is useful for the diagnosis of MRCLs. Detection of FUS - CHOP fusion transcript in paraffin - embedded material by nested RT - PCR is feasible.