多克隆分离探针在Xp11．2易位性肾癌诊断中的应用

Application of polyclonal break-apart probes in the diagnosis of Xpll. 2 translocation renal cell carcinoma

目的利用自行设计的荧光原位杂交（FISH）多克隆分离探针，检测Xpll．2易位／TFE3基因融合相关性肾癌（Xpll．2易位性肾癌）中特征性的TFE3基因易位，探讨该探针在诊断Xpll．2易位性。肾癌中的应用价值。方法收集南京大学医学院附属鼓楼医院2006至2013年临床诊断的30例肾癌病例，包括10例依据组织形态和转录因子E3（TFE3）免疫组化诊断的Xpll．2易位性肾癌，10例肾透明细胞癌，10例肾乳头状腺癌。根据Xpll．2易位性肾癌基因改变类型，设计针对性的多克隆分离探针，并在肿瘤石蜡包埋组织切片上使用该探针进行FISH检测，通过荧光显微镜观察组织切片中的荧光信号类型，判断肿瘤组织中是否存在TFE3基因的易位。结果30份肿瘤组织切片均成功进行FISH检测。10份依据组织形态和TFE3免疫组化诊断的Xpl1．2易位性肾癌标本中，9份FISH出现分离信号并达到阈值，检测为阳性，符合Xpll．2易位性肾癌诊断；1份只出现融合信号，检测为阴性，不符合Xpll．2易位性肾癌诊断。10份肾透明细胞癌和10份肾乳头状腺癌标本FISH只出现融合信号，检测均为阴性。结论单纯依靠组织学特征和免疫组化诊断Xpll．2易位性肾癌存在误诊的可能。利用FISH多克隆分离探针可以检测出Xpll．2易位性肾癌特征性的TFE3基因易位，是一种诊断Xpll．2易位性肾癌相对准确和客观的方法。

Objective To explore the value of self-designed fluorescent in situ hybridization （FISH） polyclonal break-apart probes specific for TFE3 gene in the diagnosis of Xpll. 2 translocation renal cell carcinoma. Methods All tissue samples were collected from 2006 to 2013, including Xpll. 2 translocation renal cell carcinoma （ n = 10 ）, renal clear cell carcinoma （ n = 10 ） and renal papillary cell carcinoma （n = 10 ）. FISH was conducted for paraffin-embedded tumor tissue sections with probes. The types of fluorescence were observed by fluorescent microscopy to determine the existence or non-existence of translocated TFE3 gene. Results All sections were successfully probed. The split red and green signals within a single nucleus were detected simultaneously in 9 cases of Xpl 1.2 translocation renal cell carcinoma as diagnosed by traditional pathological and immunohistochemical methods. And it was consistent with the initial diagnosis. Detection of fusion signal in 1/10 and negative FISH result did not conform to the initial diagnosis. The fluorescent types of renal clear cell carcinoma and renal papillary cell carcinoma were all fusion signals. FISH tests were negative for renal clear and papillary cell carcinomas. Conclusions Xpl 1.2 translocation renal cell carcinomas diagnosed by traditional pathological and immunohistochemical methods are sometimes misdiagnosed. Detecting the translocation of TFE3 gene with FISH polyclonal break-apart probes is both accurate and reliable for diagnosing Xpl 1.2 translocation renal cell carcinoma.