Jay V, Pienkowska M, Becker L, Zielenska M
Department of Pathology, Hospital for Sick Children-University of Toronto, Ontario, Canada.
Mod Pathol. 1995 Jun;8(5):488-91.
Cytogenetic analysis of peripheral primitive neuroectodermal tumors (PNETs) has demonstrated a consistent primary chromosomal change characterized by a reciprocal translocation t(11;22)(q24:q12). In the central nervous system PNETs, most frequent of which are the cerebellar medulloblastomas, the most prevalent chromosomal abnormalities include deletions and unbalanced translocations. The recent cloning of the t(11;22) breakpoint has revealed the fusion of the human FLI-1 gene on chromosome 11q24 with a gene EWS on chromosome 22q12 and permitted detection of fusion transcripts. Molecular genetic analysis for the presence of EWS/FLI-1 fusion transcripts by the reverse transcriptase-polymerase chain reaction has recently been applied to peripheral PNETs. In the present study, we analyzed eight central PNETs by reverse transcriptase-polymerase chain reaction for EWS/FLI-1 fusion transcripts. The tumors included six PNETs of the cerebellum, one supratentorial PNET of the frontal lobe and one PNET of the pineal region. Polymerase chain reaction analysis in all eight cases failed to reveal a t(11;22) translocation indicating that this is not a cytogenetic abnormality of the central PNETs. Reverse transcriptase-polymerase chain reaction analysis of EWS/FLI-1 fusion transcripts provides a novel adjunctive tool in the differentiation of central versus peripheral PNET.
外周原始神经外胚层肿瘤（PNETs）的细胞遗传学分析显示，其主要染色体改变具有一致性，特征为相互易位t(11;22)(q24:q12)。在中枢神经系统PNETs中，最常见的是小脑髓母细胞瘤，最普遍的染色体异常包括缺失和不平衡易位。最近对t(11;22)断点的克隆揭示了位于11q24染色体上的人类FLI-1基因与位于22q12染色体上的EWS基因融合，并使得融合转录本得以检测。通过逆转录聚合酶链反应对EWS/FLI-1融合转录本的存在进行分子遗传学分析，最近已应用于外周PNETs。在本研究中，我们通过逆转录聚合酶链反应分析了8例中枢PNETs中的EWS/FLI-1融合转录本。这些肿瘤包括6例小脑PNETs、1例额叶幕上PNET和1例松果体区PNET。所有8例病例的聚合酶链反应分析均未发现t(11;22)易位，表明这不是中枢PNETs的细胞遗传学异常。对EWS/FLI-1融合转录本进行逆转录聚合酶链反应分析，为中枢与外周PNET的鉴别提供了一种新的辅助工具。
