Overexpression of the pseudoautosomal gene MIC2 in Ewing's sarcoma and peripheral primitive neuroectodermal tumor.
Overexpression of the pseudoautosomal gene MIC2 in Ewing's sarcoma and peripheral primitive neuroectodermal tumor.
复制标题
假常染色体基因 MIC2 在尤文氏肉瘤和外周原始神经外胚层肿瘤中的过度表达。
作者：
Heinrich Kovar;Michael N. Dworzak;S. Strehl;E. Schnell;I. Ambros;Peter F. Ambros;Helmut Gadner
尤文氏肉瘤（ES）是儿童和青少年第二常见的骨肿瘤，与可能密切相关的外周原始神经外胚层肿瘤（pPNET）在11号和22号染色体之间有一个独特的细胞遗传学易位。它们都在其细胞表面暴露大量的糖蛋白，这可以通过mAb HBA-71特异性检测。通过筛选从pPNET衍生的细胞系构建的cDNA表达文库，分离编码HBA-71抗原的cDNA。核苷酸测序显示HBA-71抗原是先前在造血细胞中通过mAb 12 E7鉴定的假常染色体基因MIC 2的产物。这种抗原是一种分子量约为29，000的糖蛋白，在大多数人细胞系中表达量很低，可能在正常组织和肿瘤中表达，只有少数例外。在T细胞中，抗原参与细胞粘附过程。在ES和pPNET衍生的细胞系中，MIC 2表达显著增强。未观察到翻译后修饰的大体变化。高表达导致在石蜡包埋组织切片的免疫细胞化学分析中容易且特异地检测抗原，使得HBA-71在肿瘤诊断中成为有用的工具。
Ewing's Sarcoma (ES), the second most frequent bone tumor in childhood and adolescence, and the probably closely related peripheral primitive neuroectodermal tumor (pPNET) share a unique cytogenetic translocation between chromosomes 11 and 22. Both of them expose high amounts of a glycoprotein on their cell surface, which can be specifically detected by the mAb HBA-71. The cDNA coding for the HBA-71 antigen was isolated by screening a cDNA expression library constructed from a pPNET-derived cell line. Nucleotide sequencing revealed the HBA-71 antigen to be the product of the pseudoautosomal gene MIC2 previously identified by the mAb 12E7 in haematopoietic cells. This antigen is a glycoprotein with a molecular weight of about 29,000 and is expressed in low amounts in most human cell lines and probably normal tissues and tumors with only a few exceptions. In T-cells the antigen is involved in cell adhesion processes. In ES- and pPNET-derived cell lines MIC2 expression is significantly enhanced. No gross changes in posttranslational modification could be observed. The high expression results in easy and specific detection of the antigen in immunocytochemical analysis of paraffin embedded tissue sections making HBA-71 a useful tool in tumor diagnosis.