Additional value of K-ras point mutations in bronchial wash fluids for diagnosis of peripheral lung tumours

The purpose of this study was to examine the additional diagnostic value of K-ras point mutations in the clinical diagnosis of peripheral lung tumours . To this end, bronchial wash fluids obtained during bronchoscopy from patien ts suspected of having lung cancer were studied. Only those patients were i nvestigated for whom the cytological diagnosis was not conclusive for malig nancy. As a control group, patients without lung cancer were investigated. The method of "point mutation detection using the exonuclease amplification coupled capture technique" (Point-EXACCT) for analysis of K-ras codon 12 w as performed in bronchial wash fluids and the corresponding tumour tissue, if available. K-ras point mutations were identified in 4 out of 19 (21%) bronchial wash f luids from patients without a decisive diagnosis of malignancy. The diagnos is of malignancy was further based on cytological examination of bronchial brush specimens, perthoracic needle aspiration, histological investigation of biopsy and resection specimens, needle aspiration of a lymph node in the neck and pleural fluid examination, Four of the patients who were R-ms-pos itive yielded positive malignant tissue via bronchoscopy even though the br onchial wash was negative for malignancy. The bronchial wash was positive f or K-ras in two of the four patients whose tumour tissue demonstrated the R -uas mutations. Analysis of bronchial wash fluids from 11 patients without lung cancer revealed no K-ras codon 12 mutations. In conclusion, R-rns point mutations can be identified in bronchial wash fl uids obtained during bronchoscopic procedures. R-uns can be used as a bioma rker in the clinical diagnosis of lung cancer and may serve as an adjunct t o cytology in lung cancer diagnosis.