Telomerase as a potential marker for inflammation and cancer detection in bronchial washing: a prospective study

The diagnosis of lung cancer remains difficult especially in peripheral tumors, given the absence of relevant markers and of sensitive imaging techniques. Telomerase is a ribonucleotide enzyme responsible for the immortalization of cancerous cells and seems to increase in bronchial aspirates of lung cancer patients. The purpose of our study is to further investigate the value of telomerase measurement in bronchial aspirates as a diagnostic tool for lung cancer.

Random 82 bronchial aspirates were obtained from patients undergoing bronchoscopy to diagnose any lung illness including inflammation and cancer. Cytology examination, quantification of proteins by Bradford method, and telomerase activity measurement by quantitative Real-time PCR were performed. Out of 82 specimens, 11 were excluded because of hemolysis, absence of elements or lack of final diagnosis. ROC curve analysis was done.

A significant difference in telomerase activity average was noted between normal patients and those with inflammation and cancer. Discriminatory capacity of telomerase activity was: for cancer vs. non cancer, AUC =0.74 (95% CI: 0.62-0.84), sensitivity=78%, specificity=72%, Negative Predictive Value=87%, at cut-off >0.46 atmol/mg protein/20 min; for cancer vs. normal, AUC=0.87 (95% CI: 0.72-0.96), se=78%, sp=92%, NPV=71%, at cut-off >0.46; for cancer vs. inflammation, AUC=0.69 (95% CI: 0.55-0.80), se=74%, sp=70%, NPV=79%, at cut-off >1.03, and for inflammation vs. normal, AUC=0.76 (95% CI: 0.62-0.88), se=79%, sp=77%, NPV=59%, at cut-off >0.

Telomerase activity in bronchial aspirates is a promising diagnostic marker for lung cancer and inflammation detection.