Thorner P
Department of Pathology, Hospital for Sick Children, Toronto, Ontario, Canada.
Pediatr Pathol Lab Med. 1996 Jan-Feb;16(1):161-9.
The presence of t(11;22)(q24;q12) is often considered diagnostic of Ewing sarcoma and peripheral primitive neuroectodermal tumor (pPNET). We report a case of a polyphenotypic tumor that possessed this translocation as detected by reverse transcriptase polymerase chain reaction (RT-PCR). This tumor was positive for vimentin, desmin, low-molecular-weight keratin, neuron-specific enolase, S-100 protein, and CD57 by immunohistochemistry. Of note, the tumor was negative for MIC2. The tumor had double-minute chromosomes with > 100 copies of the MDM2 gene. Thus, the presence of the t(11;22)(q24;q12) translocation should not be considered diagnostic of Ewing sarcoma and pPNET in the absence of supporting histologic evidence such as positive staining for MIC2. The presence of this translocation in Ewing sarcoma and pPNET has been taken as evidence that these two tumors are related. Rather than extending this relationship to include some polyphenotypic tumors, other tumors may acquire this genetic change during tumor progression. Treatment regimens for tumors may be better based on phenotype rather than genotype when these two profiles are seemingly in conflict.
t(11;22)(q24;q12)的存在通常被认为是尤因肉瘤和外周原始神经外胚层肿瘤（pPNET）的诊断依据。我们报告一例多表型肿瘤病例，通过逆转录聚合酶链反应（RT-PCR）检测发现该肿瘤存在这种易位。免疫组织化学检测显示，该肿瘤波形蛋白、结蛋白、低分子量角蛋白、神经元特异性烯醇化酶、S-100蛋白和CD57呈阳性。值得注意的是，该肿瘤MIC2呈阴性。肿瘤具有双微体染色体，MDM2基因拷贝数>100。因此，在缺乏如MIC2阳性染色等支持性组织学证据的情况下，t(11;22)(q24;q12)易位的存在不应被视为尤因肉瘤和pPNET的诊断依据。尤因肉瘤和pPNET中这种易位的存在被视为这两种肿瘤相关的证据。与其将这种关系扩展到包括一些多表型肿瘤，其他肿瘤可能在肿瘤进展过程中获得这种基因改变。当这两种特征看似冲突时，基于表型而非基因型制定肿瘤治疗方案可能更好。
