Abstract 4703: Telomerase activity in bronchial aspiration is a potential marker for inflammation and cancer detection: A prospective study.

Background: Lung cancer is the leading cause of cancer death in the United States for both men and women. Bronchoscopy is one of the major tools, along with bronchial aspirates, brushings, biopsies and bronchoalveolar lavage, used to obtain specimens revealing the diagnosis in more than 85% of cases. The diagnosis remains difficult especially in distal tumors, given the absence of a relevant marker and/or sensitive imaging technique. Telomerase is a ribonucleotide enzyme that elongates telomeres and is responsible for the immortalization of cancerous cells. This enzyme, that is expressed in more than 90% of cancers, seems to increase in bronchial aspirates of patients with lung cancer. Purpose: The objective of our study is to further investigate the value of telomerase measurement in the bronchial aspirates as a diagnostic tool for lung cancer. Methods: Random 82 bronchial aspirates were obtained from patients undergoing bronchoscopy to diagnose any lung illness type including inflammation and cancer. Patient consent form was filled. The bronchial aspirates were divided for cytology examination and telomerase activity measurement. The latter were washed twice with ice-child phosphate buffer, observed by microscope, treated with lysis buffer, incubated 30 minutes on ice and then centrifuged at 14 000 rpm at 4oC for 25 minutes. The supernatant was used to quantitate proteins using Bradford reagent and to measure telomerase activity by quantitative Real-time PCR technique. Out of 82 specimens, 11 were excluded because of high hemolysis that interfered with the technique and/or because of the complete absence of cells or elements. Results: A significant difference in telomerase activity average was noted between normal patients and those with inflammation and cancer (0.27, 3.83 and 19.96 atmol/mg protein/20min, p Operating Characteristic) curve, telomerase activity was predictive of cancer vs. non cancer conditions (including normal and inflammation), area under the curve (AUC) = 0.74 [(95% CI: 0.62-0.84); sensitivity (se) =78%, specificity (sp) =72%, Negative predictive value (NPV) = 87%, at cut-off >0.46]. Telomerase activity was also predictive of cancer vs. normal condition, AUC=0.87 [(95% CI: 0.72-0.96); se=78%, sp=92%, NPV = 71%, at cut-off >0.46]. Its predictive power of cancer vs. inflammation was AUC=0.69 [(95% CI: 0.55-0.80); se=74%, sp=70%, NPV = 79%, at cut-off >1.03], and of inflammation vs. normal condition was AUC=0.76 [(95% CI: 0.62-0.88); se=79%, sp=77%, NPV = 59%, at cut-off >0].Conclusion: The detection of telomerase activity in bronchial aspirates is a promising diagnostic marker for lung cancer and inflammation detection. Citation Format: George Hilal, Najib Nassani, Georges Khayat. Telomerase activity in bronchial aspiration is a potential marker for inflammation and cancer detection: A prospective study. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4703. doi:10.1158/1538-7445.AM2013-4703