为探讨纤维文气管镜直视下毛刷脱落细胞中H－ras基因突变在肺癌中的诊断价值。采用在纤维支气管镜直视下毛刷脱落细胞中应用PCR－RFLP方法（polymerasechainreactionrestrictionfragmentlengthpolymorphisms）检测H－ras基因点突变。对14例肺部疾病患者进行了检测。结果显示有7例首先在纤维文气管镜刷检的脱落细胞中发现H－ras基因点突变。而同时的细胞学检查为阴性，追踪观察1～8个月，病理诊断为肺癌。提示该方法是对可疑肺癌患者动态观察协助确诊的新手段。 To investigate the diagnostic value of H-ras gene mutations in brush exfoliated cells under direct vision of fiber bronchoscope in lung cancer. The point mutations of H-ras gene were detected by polymerase chain reaction restriction fragment length polymorphisms (PCR-RFLP) in cells exfoliated by brush under direct fiberoptic bronchoscopy. Fourteen patients with lung disease were tested. The results showed that H-ras gene mutations were first detected in exfoliated cells in the fibrous trachea brush scan in 7 cases. At the same time, cytology was negative, and the pathological diagnosis was lung cancer. It is suggested that this method is a new means to assist dynamic diagnosis of suspected lung cancer patients.