OLC1Protein Levels In Plasma Of Patients With Non Small Cell Lung Cancer And Its Clinical Application

BACKGROUND&AIM Lung cancer is a leading cause of cancer death throughout the world. Overall,the5-year survival rate is approximately10-16%, whereas the5-year survival rate for patients of stage IA with surgical resection is over70%. Therefore we need a more thorough study to know the biological behavior of lung cancer and to find some new detecting methods at the early stage. We analyzed the proteins released into serum-free conditioned medium (CM) by lung cancer and adjacent normal bronchial cells by short-time culture, and established lung cancer related database (over1200proteins).We were aiming at detecting the plasma concentration of OLCl (overexpressed in lung cancer1) protein, as a potential cancer biomarker, and evaluating its clinical application value in the diagnosis of non-small cell lung cancer (NSCLC).Methods we prepared OLCl antibody with OLC1full length protein, in5-6week old BALB/c mice. Each mouse was immunized four times with the dosage of15-30μg antigen protein, and the interval between two consecutive immunizations was two weeks. Antibody screening was realized through ELISA and Western blot, and a double antibody sandwich ELISA kit was developed. We used this established ELISA kit to detect the plasma concentration of OLC1protein in281NSCLC patients,54benign disease and92gender and age matched healthy controls. Area under the receiver operating characteristic curve (AUC) was used to evaluate the detection efficacy of OLC1.Results We obtained11OLC1monoclone antibodies and successfully established the ELISA kit to detect the plasma concentration of OLC1with the detecting range from1.95ng/ml to62.50ng/ml.1. OLC1concentration in case group (mean±SD,186.4±174.1ng/ml) was significantly higher than that in the control group(mean+SD,109.1+100.Ong/ml, P<0.001). In the scenario of distinguishing NSCLC from control group, AUC result was0.69. When the cutoff was set at67.72ng/ml, sensitivity and specificity was84.34%and51.09%, respectively. In the scenario of distinguishing early lung cancer (IA) from control group, AUC, sensitivity and specificity was0.68,77.78%and54.35%, respectively.2. OLC1concentration in case group (mean±SD,186.4±174.1ng/ml) was not higher than that in benign disease group(mean±SD,186.4±222.8ng/ml,P>0.05). However, OLC1concentration in benign disease group(mean±D,186.4±222.8ng/ml) was higher than healthy control group.3.OLC1concentration in patients of NSCLC with smoking (mean±SD,182.0±146.6ng/ml)was higher than non-smoking patients (mean±SD,191.2±195.6ng/ml, P>0.05).Conclusion The plasma concentration of OLC1protein was significantly elevated in NSCLC patients. Therefor, OLC1can be applied in clinical diagnosis as a potential cancer biomarker. There was no significant correlation between the protein levels of OLC1and lung cancer patients’clinical characteristics. OLC1concentration in NSCLC patients was not affected by smoking and was also elevated in benign disease patients.