Schär B K, Otto V I, Hänseler E
Institute of Clinical Chemistry, University Hospital, Zurich, Switzerland.
Cancer Res. 1997 Sep 1;57(17):3841-6.
We have developed a reverse transcription-PCR method that clearly distinguishes between the RNA transcripts of all four alkaline phosphatase (AP) genes. If compared to the methods used up to the present, the main advantages of the reverse transcription-PCR method presented are its specificity and high sensitivity. The germ cell AP and the placental AP, which are the two most closely related AP isoenzymes (98% homology), can clearly be distinguished without any interference by other AP isoenzymes. An enhanced expression of AP isoenzymes has been reported for various tumors. The examination of the pattern of AP isoenzyme expression in a specific tumor and the corresponding tissue of origin enables discrimination between eutopically and ectopically expressed isoenzymes and thus represents an important tool in the elucidation of AP isoenzymes as potential tumor markers. The pattern of AP expression in 15 germ cell tumors, 2 germinal epithelia adjacent to seminoma, 2 cell lines of germ cell tumor origin (Tera-1 and BeWo), and 5 normal testes was studied. In comparison to normal testes, in all seminomatous germ cell tumors eutopic expression of germ cell AP and ectopic expression of tissue-nonspecific AP were demonstrated. In both samples of pure embryonal carcinoma and in the embryonal carcinoma cell line, the transcription of all four mRNAs was shown. These results indicate that the expression of the isoenzymes depends on the degree of differentiation of a tumor and that a simultaneous up-regulation of all AP isoenzymes in all types of germ cell tumors does not exist.
我们开发了一种逆转录聚合酶链反应（RT-PCR）方法，该方法能够清晰地区分所有四种碱性磷酸酶（AP）基因的RNA转录本。与目前使用的方法相比，所提出的RT-PCR方法的主要优点在于其特异性和高灵敏度。生殖细胞AP和胎盘AP是两种关系最为密切的AP同工酶（同源性为98%），能够在不受其他AP同工酶干扰的情况下被清晰区分。据报道，多种肿瘤中AP同工酶的表达增强。检测特定肿瘤及其相应起源组织中AP同工酶的表达模式，能够区分异位表达和原位表达的同工酶，因此是阐明AP同工酶作为潜在肿瘤标志物的重要工具。我们研究了15例生殖细胞肿瘤、2例紧邻精原细胞瘤的生发上皮、2株生殖细胞肿瘤来源的细胞系（Tera-1和BeWo）以及5例正常睾丸中AP的表达模式。与正常睾丸相比，在所有精原细胞性生殖细胞肿瘤中均显示出生殖细胞AP的原位表达以及组织非特异性AP的异位表达。在纯胚胎癌的两个样本以及胚胎癌细胞系中，均显示出所有四种mRNA的转录。这些结果表明，同工酶的表达取决于肿瘤的分化程度，且在所有类型的生殖细胞肿瘤中不存在所有AP同工酶同时上调的情况。
