Prognostic significance of serum vascular endothelial growth factor and Angiopoietin-2 in patients with lung cancer

Vascular endothelial growth factor (VEGF) and Angiopoietin-2 (Ang-2) are major angiogenic mediators in neovascularization process. In current literature both biomarkers are discussed separately and only for non-small cell lung cancer (NSCLC). So in this study we aimed to examine them together for both cell types NSCLC and small cell lung cancer (SCLC). 100 patients with lung cancer were enrolled to this single center study. 87 of patients were diagnosed with NSCLC including 28 adenocarcinomas and 59 squamous cell cancers and 13 were SCLC. Results were compared with 30 healthy volunteers. Pre-treatment serum VEGF and Ang-2 levels were measured by using ELISA method. While serum Ang-2 levels were higher in patients than healthy controls (23395 pg/mL vs. 4025 pg/mL, p< 0.001), VEGF levels didn't differ (2308 pg/mL vs. 2433 pg/mL, p> 0.05). There was no difference between cases with SCLC and NSCLC in terms of Ang-2. But serum VEGF values were significantly lower in SCLC than NSCLC and control groups. None of these mediators were correlated with cell type, tumor size, TNM staging, performance status and operability. VEGF levels were higher in patients with chronic obstructive pulmonary disease (COPD), but it was not significant. Three cut of values were determined according to sensitivity and specificity by using youden index. They were 8515.73 pg/mL (sensitivity 78%, specificity 76%), 7097 pg/mL (sensitivity 80%, specificity 70%) and 11063.48 pg/mL (sensitivity 76%, specificity 70%). Patients with SCLC had shorter survival time above cut-off values (p> 0.05). VEGF and Ang-2 showed a weak positive correlation (p= 0.1 and r= 0.638). In conclusion, serum VEGF wasn't useful to predict lung cancer, prognosis or cell type. Albeit Ang-2 was higher in patients with lung cancer without any effect on survival. Due to the heterogeneity of the studies done with serum measurement Ang-2 on tumor tissue should be more meaningful.