Satake N, Urakami S, Hirayama Y, Izumi K, Hino O
Department of Experimental Pathology, Cancer Institute, Tokyo, Japan.
Int J Cancer. 1998 Sep 11;77(6):895-900. doi: 10.1002/(sici)1097-0215(19980911)77:6<895::aid-ijc16>3.0.co;2-0.
A number of cancer genes have been identified by the study of hereditary human cancers and shown to be involved in sporadic genesis of the same tumors. We have identified a germline mutation in the rat homologue of the human tuberous sclerosis (TSC2) predisposing gene in the Eker rat model. In this study, we searched for mutations of the Tsc2 gene in chemically induced non-Eker rat renal cell carcinomas (RCs). N-ethyl-N-hydroxyethylnitrosamine (EHEN)- and diethylnitrosamine (DEN)-induced non-Eker rat primary RCs were subjected to polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) analysis using specific primers covering all exons of the Tsc2 gene (41 coding exons and 1 non-coding exon). We simultaneously searched for mutations in the Vhl gene, a rat homologue of von Hippel-Lindau disease (VHL) gene, as well as the Tsc2 gene. Mutations in the Vhl gene were not detected in any rat RCs (0/8). In contrast, Tsc2 gene mutations were detected at a high frequency in EHEN-induced RCs (2/3) and DEN-induced RCs (3/5) (total 5/8) (p < 0.05). By a direct cloning approach utilizing PCR analysis in 2 applicable cases, we could demonstrate the presence of intragenic somatic mutations in both alleles of the Tsc2 gene. Our results suggest that Tsc2 gene inactivation plays an important role in EHEN- and DEN-induced RCs as well as in Eker rat RCs.
通过对人类遗传性癌症的研究，已经鉴定出许多癌症基因，并表明它们参与了相同肿瘤的散发性发生。我们在Eker大鼠模型中，在人类结节性硬化症（TSC2）易感基因的大鼠同源物中鉴定出了一种种系突变。在本研究中，我们在化学诱导的非Eker大鼠肾细胞癌（RCs）中寻找Tsc2基因的突变。使用覆盖Tsc2基因所有外显子（41个编码外显子和1个非编码外显子）的特异性引物，对N-乙基-N-羟乙基亚硝胺（EHEN）和二乙基亚硝胺（DEN）诱导的非Eker大鼠原发性RCs进行聚合酶链反应-单链构象多态性（PCR-SSCP）分析。我们同时在von Hippel-Lindau病（VHL）基因的大鼠同源物Vhl基因以及Tsc2基因中寻找突变。在任何大鼠RCs中均未检测到Vhl基因突变（0/8）。相比之下，在EHEN诱导的RCs（2/3）和DEN诱导的RCs（3/5）中，Tsc2基因突变的检测频率很高（总计5/8）（p < 0.05）。通过在2个适用病例中利用PCR分析的直接克隆方法，我们能够证明Tsc2基因的两个等位基因中均存在基因内体细胞突变。我们的结果表明，Tsc2基因失活在EHEN和DEN诱导的RCs以及Eker大鼠RCs中起重要作用。
