MicroRNA-155 expression in exhaled breath condensate of patients with lung cancer

Abstract

Background: Nowadays, microRNAs (miRNAs) have proved their significant role in the diagnosis and prognosis of various types of malignancy. Accordingly, this study aimed at evaluating the role of miRNA-155 in diagnosis as well as prognosis of lung cancer. Methods: In this prospective case-control study, exhaled breath condensate (EBC) samples were collected from a group of 15 pathologically-confirmed, chemotherapy/radiotherapy-naïve lung cancer patients, as well as from another control group comprised of 15 patients at high risk for lung cancer development. The expression of miRNA-155 (RQ value) in EBC samples was measured using Quantitative real time Polymerase Chain Reaction (PCR). Results: There was significant statistical difference between the lung cancer group and the control group as regards RQ value (p ≤ .01) being higher among the lung cancer group. RQ value among the lung cancer group showed significant statistical difference as regards tumor extension (p = .004), and smoking index (p = .004). RQ levels correlated significantly with tumor extension (p = .001), smoking status (p = .000), smoking index (p = .000), and family history of lung cancer (p = .007), whereas tumor location, histopathological type of the tumor, and sex did not correlate significantly (p > .05). The best cut-off value for EBC RQ level was ≥3.338 with an overall sensitivity 100%, specificity 100%, positive predictive value 100%, negative predictive value 100%, and overall accuracy 100%. Conclusion: The expression of miRNA-155 in EBC can be considered as an accurate, non-invasive, promising biomarker for early lung cancer diagnosis and prognosis.

Keywords

• Lung cancer
• miRNA-155
• Exhaled breath condensate
• PCR