中文摘要：

背景与目的RAP2B是我们实验室构建的中国人肺鳞癌差异表达cDNA文库中高表达的基因之一。作为具有保守结构域的Ras超家族成员，RAP2B基因在肿瘤发生发展中的作用仍属未知。本文拟初步探讨RAP2B基因在肺癌中的作用及其机制。方法应用半定量RT—PCR方法检测了27例手术切除的肺鳞癌肿瘤组织和相应的癌旁组织中RAP2B基因的表达；结合生物信息学分析克隆全长ORF区并转染大鼠Ratl细胞，观察转化灶形成情况；采用NF—kappaB信号通路特异的报告基因观察RAP2B基因对NF—kappaB通路的影响。结果RAP2BmRNA在约67％（18／27）的肺鳞癌配对组织中肿瘤较癌旁组织高表达；成功构建了RAP2B的真核表达质粒；平板转化实验显示转染尺RAP2B基因的细胞出现明显转化灶；通路报告基因分析显示RAP2B能够明显激活NF—kappaB通路。结论RAP2B基因在肺癌患者的肿瘤组织高表达，在体外具有恶性转化Rat1细胞能力，提示其为候选癌基因，并且可能通过激活NF—kappaB信号通路在肺癌发生发展中发挥作用。

英文摘要：

Background and objective RAP2B is one of the 50 novel candidate genes cloned from the differential expression cDNA libraries constructed in lung cancer cells. Though RAP2B contains conserved domain and belongs to Ras superfamily, the function of RAP2B in carcinogenesis is still poorly understood. The aim of this study is to explore the roles of RAP2B gene in carcinogenesis. Methods RT-PCR was applied to examine transcriptional status of RAP2B in the tumor and corresponding adjacent tissues collected from 27 patients with lung squamous cell carcinoma. RAP2B expression plasmid was constructed and transfected into Ratl cells to evaluate the in vitro transformation ability through colony formation assay. Reporter gene assay was performed to reveal the relationship between RAP2B gene and NF-kappaB pathway. Results About 67% （18/27） of tumor tissues show higher mRNA expression than that in the corresponding adjacent normal tissues. Typical transforming focus formation was observed in Ratl cells which were transfected with RAP2B gene. The reporter gene assay data showed that RAP2B activated NF-kappaB pathway more than 3 folds compared with the mock vector. Conclusion RAP2B may be a novel candidate oncogene that plays important roles in carcinogenesis through activation of NF-kappaB pathway.