采用逆转录聚合酶链反应（ＲＴＰＣＲ） 技术检测４０例不同肿瘤病理、临床分期的肺癌组织中诱生型一氧化氮合酶 （ｉＮＯＳ） ｍ ＲＮＡ的表达情况。结果表明， 肺癌组ｉＮＯＳｍ ＲＮＡ阳性表达率为７２５０％ ， 较对照组（１１７６％ ） 明显增高（Ｐ＜ ００１）。ｉＮＯＳ阳性表达与病理学类型无关， 与细胞分化程度呈负相关。早期肺癌ｉＮＯＳ阳性率（８７５０％ ） 显著高于晚期肺癌的阳性率（５０００％ ）。提示肺癌组织中存在ｉＮＯＳ， 它可能通过合成一氧化氮（ＮＯ） 在分子水平参与了肺癌的发生、发展。 Reverse transcription polymerase chain reaction (RT-PCR) was used to detect the expression of inducible nitric oxide synthase (iNOS) m RNA in 40 lung cancer tissues with different pathological and clinical stages. The results showed that the positive expression rate of iNOSm RNA in lung cancer group was 7250%, which was significantly higher than that in the control group (1176%) (P<001). The positive expression of iNOS was not related to the type of pathology and negatively correlated with the degree of cell differentiation. The positive rate of iNOS in early stage lung cancer (8750%) was significantly higher than that in advanced stage lung cancer (5000%). It suggests that iNOS exists in lung cancer tissues, which may be involved in the occurrence and development of lung cancer at the molecular level through the synthesis of nitric oxide (NO).