OBJECTIVETo investigate aberrant methylation in the promoter of p16 gene in the sediment cells of pleural effusion and evaluate its clinical significance in the differentiating benign and malignant pleural effusion.

METHODSUsing methylation-specific PCR (MSP), aberrant promoter methylation of p16 gene was detected in the sedimental cells of pleural effusion samples from 66 patients with pleural effusion.

RESULTSOf the 66 patients with pleural effusion, 36 had a definite diagnosis of malignant pleural effusion, and the rest were confirmed to have benign pleural effusion. The positivity rate of p16 gene promoter methylation was 69.4% (25/36) in malignant pleural effusion and 13.3% (4/30) in benign pleural effusion specimens, showing a significant difference between them (χ² = 20.915, P < 0.01). The diagnostic sensitivity, specificity and accuracy of aberrant promoter methylation of p16 gene in the 36 malignant cases were 69.4%, 86.7% and 77.3%, respectively. The positive expression of p16 gene promoter methylation in malignant pleural effusion was not correlated to the histological type or the pathological grade of the tumor (P > 0.05).

CONCLUSIONDetection of aberrant methylation in p16 gene promoter in the sediment cells of pleural effusion specimens by MSP method allows differentiation between benign and malignant pleural effusion.