痰液癌基因突变的检测在肺癌诊断中的应用

目的从分子生物学检测角度来寻求敏感的肺癌诊断新方法。方法应用多聚合酶链反应（ＰＣＲ）结合限制性长度片段多态性分析法（ＲＦＬＰ）及免疫组化技术（ＩＨＣ），检测６２例肺癌和３４例肺部良性疾病患者痰标本中ｋｒａｓ、ｐ５３基因的突变状况，检测结果与组织学、脱落细胞学诊断进行对比分析。结果肺癌痰标本的脱落细胞学敏感性为６１％、阴性预计值（ＮＰＶ）为５９％；ｐ５３阳性表达的敏感性为７７％、ＮＰＶ为６６％；ｋｒａｓ变异阳性的敏感性为３４％、ＮＰＶ为４２％；ｐ５３、ｋｒａｓ和痰脱落细胞学联合检测：敏感性提高至９２％（Ｐ＜０．０５）、ＮＰＶ为８４％（Ｐ＜０．０５）。２４例痰细胞学假阴性痰标本中ｐ５３或ｋｒａｓ变异阳性１７例（７１％）。结论痰标本ｐ５３、ｋｒａｓ的联合检测可增加痰检的敏感性，补充和提高脱落细胞学的诊断价值。

Detection of oncogenic mutations in sputum and its diagnostic value of lung cancer

Objective To find a new method to molecular biological detection of lung cancer. Method The sputum specimens from 96 cases of lung cancer and other lung patients were detected for K ras and p53 mutations by using polymerase chain reaction(PCR) and restriction fragment length polymorphism and and immunohistoche mistry (IHC) tecniques. Result 38 out of 62 sputum specimens of lung cancer patients were positive for cytology: Sensitivity was 61%. NPV (negative predictive value) was 59%;p53 was overexpressed in 48 cases:Sensitivity was 77%.NPV was 66%;k ras was positive in 21 cases:Sensitivity was 34%, NPV 42%;The combination of conventional cytology and molecular screening(k ras p53) produced a sensitivity value of 92%( P < 0.05) with an NPV of 84%( P < 0.05); In 24 cases of patients whose cytology of sputum was false negtive, 17 were found either p53 or k ras positive of which 7 patients were identified to be lung cancer in the follow up study. Conclusion These results suggest that detection of oncogene mutation in sputum enhanced and added to the diagnostic value of conventional cytology. It is a promising approach to early lung cancer detection and massive screeing in terms of its rapidity,economy and simplicity.