Correlation Between Cellfree DNA As Well As The Integrity And The Pleural Thickness With Thickness Of The Pleural Malignant And Benign Pleural Disease

Objectives:Pleural thickening is mainly caused by infection and tumor which often accompanied by elevated plasma cell-free DNA(cfDNA),we investigate whether plasma cfDNA or its integrity could differentiate pleural cancer from pleurisy in patients with pleural thickening.Methods:Fifty-five patients with pleurisy and 33 patients with pleural cancer were enrolled. cfDNA levels in plasma were quantified by real-time PCR amplification of ALU gene(product size of 115 bp), and quantitative ratio of ALU(247 bp) to ALU(115 bp) reflected the integrity of cfDNA.Plasma carbohydrate antigen 125(CA125), carbohydrate antigen 199(CA199),carcinoembryonic antigen(CEA) level were quantified by flow fluorescence immunoassay.Detection of pleural thickness by B-ultrasound.Results:There were significant differences in plasma cfDNA(ALU115) and pleural thickness between the patients with pleural cancer and patients with pleurisy(5.18±1.31 mm vs 4.38±0.76 mm,P=0.005;0.30±0.16ng/ulvs0.20±0.15ng/ul,P=0.005). Plasma cfDNA level was associated with CA199 in patients with pleural cancer.Pleural cancer could be differentiated with a sensitivity of 54.2%,37.1%,74.1% and a specificity of 81%,61.5%,78.2%by pleural thickness>4.5mm(AUC = 0.715), cfDNA ALU115>0.2205 ng/ul(AUC = 0.699) and both methods respectively.Conclusions: cfDNA alone or in combination with the b-ultrasound could be applied to differentiate pleural cancer from pleurisy in patients with pleural thickness.