BACKGROUNDIncreasing evidences have shown that vascular endothelial growth factor C (VEGF-C) is involved in the tumor lymphangiogenesis via combining with its ligand, vascular endothelial growth factor receptor-3 (VEGFR-3), which is the most important factor contributing to lymph node metastasis. Futhermore, lymph node metastasis is the most familiar metastatic pathway in non-small cell lung cancer (NSCLC). Based on this knowledge, the present study aims to explore the relationship between VEGF-C and lymphangiogenesis and lymph node metastasis in NSCLC with the use of podoplanin, a novel lymphatic vessel endothelium marker to detect lymphatic vessel.

METHODSThe expression of VEGF-C and podoplanin were detected in 66 paraffin sections of NSCLC and 8 inflammatory pseudotumor tissues by immunohistochemistry (SP). Assessments of podoplanin+ lymphatic vessel density (LVD) and positive rates of VEGF-C were performed and their relationship was analysed.

RESULTSThe positive rate of VEGF-C in the inflammatory pseudotumor group (12.5%) was significantly lower than that in the NSCLC group (75.8%) (P < 0.01), the positive rate of VEGF-C in the positive lymph node group was significantly higher than that in the negative lymph node metastasis group (86.5% vs 62.1%, P < 0.05) and there was no difference between the well differentiated group and the poor differentiated group (76.3% vs 75.0%, P > 0.05). LVD in the positive VEGF-C group was significantly higher than that in the negative VEGF-C group (21.3±6.0 vs 17.7±5.1, P < 0.05), LVD in the inflammatory pseudotumor group (10.9±4.9) was distinctly lower than that in the NSCLC group (20.4±5.9) (P < 0.01) and compared with the negative lymph node metastasis group (18.5± 5.5), LVD (21.9±5.9) in the positive lymph node metastasis group increased significantly (P < 0.05).

CONCLUSIONSLymphangiogenesis is a significant factor for tumor lymphatic metastasis, VEGF-C may mediate lymphatic metastasis of NSCLC by the way of inducing lymphangiogenesis.