黏液样/圆细胞型脂肪肉瘤中FUS-CHOP mRNA和MDM_2、p53蛋白的表达

Expression of FUS-CHOP mRNA and MDM_2,p53 Protein in Myxiod/round Cell Liposarcoma

目的探讨FUS-CHOP mRNA及MDM2、p53蛋白在黏液样/圆细胞型脂肪肉瘤(MRCLs)组织中的表达。方法收集经甲醛固定、石蜡包埋的MRCLs组织标本25例。以非MRCLs的脂肪肉瘤及其他软组织肉瘤共18例作对照组。用嵌套式RT-PCR的方法检测FUS-CHOP融合基因mRNA并做DNA测序证实,以β-actin基因作为内对照。用免疫组化SP法检测25例MRCLs中MDM2、p53蛋白表达情况。结果MRCLs组和阴性对照组β-actin阳性率分别为72%(18/25)和66.7%(12/18)。25例MRCLs中15例检出Ⅱ型FUS-CHOP融合基因表达,去除β-actin阴性病例后阳性率为83.3%(14/18)。对照组18例标本均未检出FUS-CHOP融合基因。MRCLs中MDM2、p53蛋白阳性表达率分别为56%(14/25)和44%(11/25),以圆细胞为主的病例组阳性表达率最高,差异有统计学意义。FUS-CHOP融合基因与MDM2及p53蛋白表达无相关性;而MDM2与p53蛋白表达呈正相关,有统计学意义。结论(1)FUS-CHOP融合基因是MRCLs的特异性分子遗传标志物,可用于该肿瘤的诊断与鉴别诊断。(2)MRCLs中MDM2、p53蛋白表达与其预后相关。(3)MRCLs中FUS-CHOP融合基因与MDM2、p53蛋白的表达无相关性。

Objective To explore the expression of FUS-CHOP mRNA and MDM2 .p53 protein in Myxiod/round cell Liposarcoma and their significance. Methods Twenty-five formalin fixed, paraffin-embedded MRCL samples and 18 control cases retrieved from the archival files were studied. Nested reverse transcription-polymeras-ase 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 gene was used to assess the quality of the mRNA templates. All of the MRCL cases was available for immunohistochemical analysis of MDM2 and p53 status. Results 13-actin mRNA was detected in 18 MRCLs（18/25, 72%） and 12 negative control case （12/18,66. 7%）. Type Ⅱ FUS-CHOP mRNA was successfully detected in 15 out of 25（60%） MRCLs. All of control cases were negative for the FUS-CHOP fusion gene transcripts. The positive rate of MDM2 and p53 proteins were 56% （14/25）and 44% （11/25）, respectively, both of them were significantly higher in round cell liposarcoma than them in myxiod and mixed liposarcoma, There was no correlation between FUS-CHOP mRNA and the expression of p53. MDM2 protein, but there was a tendency of positive correlation between the expression of MDM2 and p53. Conclusion （1） FUS-CHOP is considered as a specific molecular and genetic hallmark for MRCLs and is useful for the diagnosis of MRCLs. （2） The expression of MDM2 and p53 protein is associated with the progression of MRCLs. （3）There is a no correlation between MDM2 .p53 and FUS-CHOP in MRCLs.