目的：建立假单孢杆菌外毒素Ａ（ＰＥＡ）基因的组织特异性抗大肠癌基因疗法。方法：用ＰＣＲ法从绿脓杆菌基因组ＤＮＡ中克隆ＰＥＡⅡ＋Ⅲ区基因，引入Ｋｏｚａｋ序列、终止信号和酶切位点，测序。构建ＰＥＡ基因转录受人癌胚抗原（ＣＥＡ）启动子调控的逆转录病毒载体。共转染法体外研究ＰＥＡ基因表达对报告基因表达的特异抑制作用。用ＤＮＡ体内直接转染法于裸鼠体内观察ＰＥＡ基因的抗人类肿瘤作用。结果：所克隆的ＰＥＡ序列与已报道序列基本相同。ＣＥＡ启动子调控的ＰＥＡ基因可在大肠癌细胞中特异性抑制荧光素酶基因表达，在裸鼠体内对人大肠癌模型的直接转染能特异抑制人大肠肿瘤的生长。结论：ＰＥＡⅡ＋Ⅲ区基因作为治疗基因，适合于大肠癌特异性基因治疗 Objective: To establish tissue-specific anti-colon cancer gene therapy for Pseudomonas exotoxin A (PEA) gene. METHODS: The PEAII+III gene was cloned from the genomic DNA of P. aeruginosa by PCR and the Kozak sequence, termination signal and restriction enzyme sites were introduced and sequenced. Construction of a retroviral vector in which PEA gene transcription is regulated by a human carcinoembryonic antigen (CEA) promoter. The co-transfection method was used to study the specific inhibitory effect of PEA gene expression on the expression of reporter gene in vitro. The anti-human tumor effect of PEA gene was observed in nude mice by direct transfection of DNA in vivo. Results: The cloned PEA sequence is essentially the same as the reported sequence. PEA gene regulated by CEA promoter can specifically inhibit luciferase gene expression in colorectal cancer cells. Direct transfection of human colorectal cancer model in nude mice can specifically inhibit the growth of human colorectal tumors. Conclusion: PEAII+III gene is a therapeutic gene suitable for colorectal cancer-specific gene therapy