Lasota J, Jasinski M, Debiec-Rychter M, Szadowska A, Limon J, Miettinen M
Department of Soft Tissue Pathology, Armed Forces Institute of Pathology, Washington, DC 20306-6000, USA.
Mod Pathol. 1998 Jul;11(7):626-33.
Identification of the t(X;18)(p11.2;q11.2) translocation and detection of the resulting SYT-SSX1 or SYT-SSX2 fusion transcripts are useful diagnostic markers for synovial sarcoma. In this study, we developed a polymerase chain reaction (PCR) assay to amplify SYT-SSX fusion transcripts. The primer sequences were designed to generate small PCR products and to amplify sequences of all known SSX genes as fusion partners for the SYT gene. RNA was obtained from formaldehyde-fixed and paraffin-embedded tissues of 22 immunohistochemically characterized synovial sarcomas, 6 of them cytogenetically confirmed as t(X;18) positive. The SYT-SSX fusion transcripts were detected in 21 of the 22 analyzed cases. The type of the fusion was identified by the specific restriction enzyme digestion pattern as SYT-SSX1 in 13 cases and SYT-SSX2 in 7 cases; in 1 case, the type could not be assigned. None of the cases showed involvement of the SSX3, SSX4, or SSX5 genes, the other members of the SSX gene family. In seven cases, the SYT-SSX1 or SYT-SSX2 fusion transcripts were demonstrated in frozen tissue using a different PCR assay. The PCR products were confirmed as SYT-SSX sequences by sequencing in five randomly selected cases. Fifteen other sarcomas and related tumors were negative for SYT-SSX fusion transcripts. The PCR assay used in this study performs well in formaldehyde-fixed and paraffin-embedded tissue, and it shows a high specificity. This assay can be used as an adjunct test for diagnostically difficult cases or in retrospective studies to refine the diagnosis of synovial sarcoma in archival material.
t(X;18)(p11.2;q11.2)易位的鉴定以及由此产生的SYT-SSX1或SYT-SSX2融合转录本的检测是滑膜肉瘤有用的诊断标志物。在本研究中，我们开发了一种聚合酶链反应（PCR）检测方法来扩增SYT-SSX融合转录本。引物序列的设计旨在产生小的PCR产物，并扩增所有已知作为SYT基因融合伴侣的SSX基因序列。从22例经免疫组织化学鉴定的滑膜肉瘤的甲醛固定石蜡包埋组织中获取RNA，其中6例经细胞遗传学证实为t(X;18)阳性。在22例分析病例中的21例检测到SYT-SSX融合转录本。通过特异性限制性内切酶消化模式鉴定融合类型，13例为SYT-SSX1，7例为SYT-SSX2；1例无法确定融合类型。所有病例均未显示SSX基因家族的其他成员SSX3、SSX4或SSX5基因受累。在7例病例中，使用不同的PCR检测方法在冰冻组织中证实了SYT-SSX1或SYT-SSX2融合转录本。在随机选择的5例病例中通过测序确认PCR产物为SYT-SSX序列。另外15例肉瘤及相关肿瘤的SYT-SSX融合转录本为阴性。本研究中使用的PCR检测方法在甲醛固定石蜡包埋组织中表现良好，且具有高特异性。该检测方法可作为诊断困难病例的辅助检测方法，或用于回顾性研究以完善存档材料中滑膜肉瘤的诊断。
