Serum vascular endothelial growth factor-C levels: A possible diagnostic marker for lymph node metastasis in patients with primary non-small cell lung cancer

Accurate tumor staging is essential for selecting the appropriate treatment strategy for lung cancer. Computed tomography (CT), or positron emission tomography (PET), is the most commonly used non-invasive staging method of lymph node (LN) metastases (LNM), but this method remains unsatisfactory. The present study measured vascular endothelial growth factor (VEGF)-C levels in serum, tumor tissue and LNs to determine the correlation between serum VEGF-C and LNM, and also assessed the usefulness of serum VEGF-C as an additional diagnostic marker for identifying LNM. A total of 66 patients with non-small cell lung carcinoma (NSCLC) or benign tumors of the lung were included in this study, and circulating VEGF-C levels were assessed with enzyme-linked immunosorbent assays. RNA fractions extracted from the tumor tissues and LNs were subjected to quantitative polymerase chain reaction (qPCR) to assess the mRNA levels of VEGF-C. The VEGF-C levels in serum, tumor tissue and LNM were significantly higher compared with the control group (P<0.05). The VEGF-C levels of patients with LNM were significantly higher compared with those without LNM (P<0.05). The VEGF-C levels in the serum, tumor tissue and LNM were significantly correlated (P<0.05). With regard to the diagnosis of LNM using VEGF-C levels, the serum levels of VEGF-C reached a sensitivity of 65.0% and a specificity of 72.2% when a cutoff value of 655.65 pg/ml was applied. Serum VEGF-C levels may provide additional information for distinguishing between the absence and presence of LNM in patients with lung carcinoma. The evaluation of serum VEGF-C is complementary to accurate LN staging in NSCLC.