目的　探讨p53蛋白作为肿瘤标志物在肺癌诊断中的意义。方法　应用免疫组织化学方法对 57例胸液细胞学标本和 69例纤维支气管镜肺活检标本作p53蛋白的检测。结果　p53蛋白在胸液细胞学标本中保存较好 ,细胞学诊断为良性、可疑肺癌、肺癌者 ,p53蛋白阳性率分别为 0 % (0 /2 7)、3 3 .3 % (2 /6)、54 .2 % (1 3 /2 4)。纤维支气管镜肺活检标本中 ,组织学诊断为良性、不典型增生和恶性肿瘤者 ,p53蛋白阳性率分别为 0 % (0 /2 3 )、1 4.3 % (1 /7)和 3 5.9% (1 4/3 9)。上述p53蛋白阳性的可疑癌和不典型增生病例经随访均证实为肺癌。结论　检测胸液细胞学标本和纤维支气管镜肺活检标本中的p53蛋白对于胸部良恶性疾病的鉴别诊断具有重要的临床意义。 Objective To investigate the significance of p53 protein as a tumor marker in the diagnosis of lung cancer. Methods Immunohistochemical method was used to detect p53 protein in 57 cases of pleural fluid cytology specimens and 69 cases of fiberoptic bronchoscopy lung biopsy specimens. Results The p53 protein was well preserved in pleural fluid cytology specimens. The cytological diagnosis was benign, suspicious lung cancer, and lung cancer. The positive rates of p53 protein were 0% (0/27), 33.3% (2/6) respectively. ), 54.2% (1 3 /2 4). In the lung biopsy specimens of the fiberoptic bronchoscope, the positive rates of p53 protein were 0 % (0/23), 14.3 % (1/7) and 3 5.9% (histologically diagnosed as benign, atypical hyperplasia, and malignant). 1 4/3 9). The above-mentioned p53 protein positive cases of suspected cancer and atypical hyperplasia were confirmed as lung cancer after follow-up. Conclusion Detection of p53 protein in pleural fluid cytology specimens and fiberoptic bronchoscopic lung biopsy specimens has important clinical significance for differential diagnosis of benign and malignant chest diseases.