目的　探讨胸水细胞中 p5 3基因突变的检测对鉴别良恶性胸水的价值 .方法　应用 PCR- SSCP方法对 34例肺癌患者和 16例良性肺部疾病患者的胸水细胞中的 p5 3基因突变情况进行了检测 .同时进行了胸水的瘤细胞学检查和部分肺癌组织的 p5 3基因突变检测 ,并将结果进行了比较 .结果　在 47.0 % (16 / 34 )的肺癌患者的胸水细胞中检测到p5 3基因的突变 ,在 37.5 % (6 / 16 )的瘤细胞学检查阴性的肺癌患者的胸水细胞中检测到 p5 3基因的突变 ,在 83.3% (5 /6 )的伴有组织 p5 3基因突变检测阳性的肺癌患者的胸水细胞中检测到 p5 3基因的突变 ,而在全部 16例良性肺部疾病患者的胸水细胞中未检测到 p5 3基因突变 .结论　突变的 p5 3基因可作为一种有价值的肿瘤标志物用于肺癌所致恶性胸水的诊断 Objective To investigate the value of p53 gene mutations in pleural effusions for the differential diagnosis of benign and malignant pleural effusions. Methods The p53 gene mutations in pleural effusions of 34 patients with lung cancer and 16 patients with benign lung disease were analyzed by PCR-SSCP. Detection. Simultaneous pleural fluid cytology and partial lung cancer p53 mutations were tested and the results compared. Results The p53 gene was detected in pleural fluid cells in 47.1% (16/34) lung cancer patients. Of the mutations, mutations in the p53 gene were detected in pleural fluid cells in 37.7% (6/16) of lung cancer patients negative for cytology, and 83.3% (5 of 6) of the patients were positive for the detection of the p53 gene mutation. The mutation in the p53 gene was detected in the pleural fluids of lung cancer patients, but p53 gene mutations were not detected in the pleural effusion cells of all 16 patients with benign lung diseases. Conclusion The mutated p53 gene can be used as a valuable marker. Tumor markers for the diagnosis of malignant pleural effusion caused by lung cancer