Pleural fluid DNA integrity index as a diagnostic marker of malignant pleural effusion

Abstract

The accurate identification of malignant cells in pleural fluid is a diagnostic problem. Aim: The aim of this study was to evaluate the value of Alu 247, Alu 115 cf- DNA levels and Alu 247/ Alu 115 ratio (DNA integrity index) in detecting malignant pleural effusion. Patients and methods: 68 patients with pleural effusion were recruited from Chest Department, Menoufia University Hospital between June 2015 and January 2016 classified into: Group I: 39 patients with malignant pleural effusion. Group II: 29 ages and sex matched patients with benign exudative pleural effusion. All patients were subjected to full history taking, clinical examination, determination of light’s criteria, cytological examination and determination of Alu 247/ Alu 115 ratio (cell free DNA integrity index) in pleural fluid by real time PCR with relative standard curve technique. Results: cell free DNA integrity index was significantly higher in malignant effusion group compared to benign one (1.35 ± 0.38 and 1.06 ± 0.45 respectively). The sensitivity of DNA integrity index was (94.9%), with specificity (86.2%), positive predictive value (75.5) and negative predictive value (92.6) at cutoff point 0.8189. While the sensitivity of the combined DNA integrity index and cytological examination was (100%), with specificity (86%), positive predictive value (91%) and negative predictive value (100%). Conclusion: pleural fluid Cell-free DNA integrity index may be a promising biomarker for detection of malignant effusion without the need for invasive diagnostic maneuvers.