BACKGROUNDTo assess the sensitivity and specificity of flow cytometry (FCM) DNA content analysis in diagnosing malignancy as well as premalignancy and to evaluate the diagnostic role of FCM DNA content analysis in fiberoptic bronchoscopic specimens of lung cancer.

METHODSFresh specimens taken by fiberoptic bronchoscope from 41 patients with lung cancer (28 squamous cell carcinoma, 2 bronchioloalveolar carcinoma, 11 small cell lung cancer) and 21 patients with non-malignant pulmonary lesions were measured for DNA index (DI), S-phase fraction (SPF) by using FACSCalibur 4200 flow cytometry. The diagnostic value of this method was compared with fiberoptic bronchoscopic biopsy, brushing and sputum examination.

RESULTS1. DI was 1.18±0.33 and 0.99±0.07 in lung cancer and non-malignant groups respectively. The percentage of heteroploid was 78.04% in lung cancer and 4.8% in non malignant. DI and the positive rate of heteroploid in lung cancer group were significantly higher than that in non-malignant group ( P < 0.01). If the presence of heteroploid was used as a diagnostic criterion, the sensitivity of DNA analysis was 78.04% and the specificity was 95.24%. There was no diagnostic sensitivity difference between FCM DNA content analysis and biopsy (90.26%) ( P > 0.05), as well as brushing (65.85%) ( P > 0.05). 2.Athough DI and the rate of heteroploid increased as the pathological grade and TNM stage advanced, there were no significant differences ( P > 0.05). 3. SPF in lung cancer group was significant higher than that in non-malignant group. The SPF of heteroploid tumors was higher than that of diploid tumors ( P < 0.05); SPF correlated with TNM stage ( P < 0.05).

CONCLUSIONSFCM DNA content analysis has an adjunctive value in diagnosis of lung cancer. The analysis of DNA content and SPF by FCM provides a beneficial method for the evaluation of tumor behavior.