Survey of new oncogenes in human germ cell tumors and function of oncogenes in differentiation of germ cell tumors

由于人类生殖细胞肿瘤发生于年轻人，与胃、肺等其他类型的肿瘤相比，该类型的肿瘤在致癌方面应具有独特的特点。因此，我们试图通过NIH3T3和EL2的转染实验，从这类肿瘤中获得新型的致癌基因。一种大鼠成纤维细胞系。因此，我们还没有能够获得新的基因。我们还分析了以前报道的几个癌基因的结构变化和异常表达，包括手术准备中的肿瘤组织和本研究建立的生殖细胞肿瘤细胞系。我们在其中一个手术准备中发现了N-myc基因的扩增，并在所有研究的细胞系中观察到该基因的异常表达，这在包括HeLa细胞在内的其他肿瘤细胞系中没有发现。这些结果表明，N-myc的表达有助于生殖细胞肿瘤的发生或维持其肿瘤状态。研究还发现，在本研究建立的生殖细胞肿瘤细胞系(NCC-IT)分化过程中，加入维甲酸后，c-myc基因的表达受到抑制，而N-myc基因的表达没有变化。

Since human germ cell tumor occurs for Young ages of human, this type of tumors should have unique features in terms of its oncogenesis, compared to other-types of tumors including stomach, and lung. Therefore, we tried to obtain new type of oncogenic genes from this type of tumors by transfection assay using NIH 3T3 and EL2. a rat fibroblast cell line. We have not been able to obtain new oneogenes as a result. We also analyzed structural alteration and unusual expression of several onco genes reported previously, in tumor tissues from operational preparations and in germ cell tumor cell lines established in this study. We found amplification of N-myc gene in one of the operational preparations and also observed unusual expression of the gene in all of the cell lines studied, which was not found in other tumor cell lines including HeLa cells. These results suggested that N-myc expression contributes to oncogenesis of germ cell tumors or maintainance of its tumor state. It was also found that c-myc gene expression was repressed during differentiation of a germ cell tumor line (NCC-IT) established in this study by addition of retinole acid, while N-myc expression did not change.