黏液样/圆细胞型脂肪肉瘤中FUS-CHOP融合基因和MDM_2蛋白的表达及意义

Expression of FUS-CHOP fusion gene and MDM_2 protein in myxoid/round cell liposarcoma and its significance

目的探讨FUS-CHOP融合基因与MDM2蛋白在黏液样/圆细胞型脂肪肉瘤(MRCLs)组织中的表达及意义。方法收集MRCLs标本25例。以非MRCLs的脂肪肉瘤及其它软组织肿瘤共18例作对照组。用嵌套式RT-PCR的方法检测FUS-CHOP融合基因mRNA并经和DNA测序证实,以β-actin基因作为内对照。用免疫组化S-P法检测25例MRCLs中MDM2蛋白表达情况。结果MRCLs组和对照组β-actin阳性率分别为72.0%(18/25)和66.7%(12/18)。25例MRCLs中15例检出型FUS-CHOP融合基因表达,阳性率为(60.0%),去除β-actin阴性病例的阳性率为83.3%(15/18)。对照组18例标本未检出FUS-CHOP融合基因。MRCLs中MDM2蛋白阳性表达率为56.0%(14/25),在圆细胞为主的病例组阳性表达率最高,差异有显著性。FUS-CHOP融合基因与MDM2蛋白表达无相关性。结论(1)MRCLs中FUS-CHOP融合基因与MDM2蛋白的表达无相关性。(2)FUS-CHOP融合基因在MRCLs中呈特异性表达,可作为该肿瘤的特异性标志物用于诊断。(3)MDM2蛋白过表达与MRCLs的进展相关。

Objective To investigate the expression of FUS-CHOP mRNA and MDM2 protein in myxoid/round cell liposarcoma （MRCLs） and its significance. Methods Twenty five formalin-fixed, paraffin-embedded MRCL samples and 18 control cases were retrieved from the archival files. Nested reverse transcription-polymerase chain reaction （RT-PCR） technique was employed to detect the FUS-CHOP mRNA expression, followed by DNA sequencing to confirm the PCR product, β-actin mRNA was used for internal quality control. Immunohistochemical staining was used to detect the expression of MDM2 protein. Results βactin mRNA was detected in 72.0% of MRCLs （18/25,） and 66.7% negative controls （12/18）. Type Ⅱ FUS-CHOP fusion transcript was successfully detected in 15 out of 25（60.0%） MRCLs. All 18 negative control cases were negative for the FUS-CHOP fusion gene transcripts. The positive rate of MDM2 protein was 56.0% （14/25）, that was much higher in round cell liposarcoma than in myxoid and mixed liposarcoma. There was a negative correlation between FUS-CHOP and MDM2. Conclusion FUS-CHOP may be used as a specific molecular and genetic hallmark in diagnosis of MRCLs. The overexpression of MDM2 protein is associated with the progression in MRCLs.