OBJECTIVETo investigate the expression of angiopoietin-2 (Ang-2) and its clinical significance in oral squamous cell carcinoma.

METHODSThe expression of Ang-2 mRNA was measured by real-time RT-PCR, and the expression of Ang-2 protein in tissue samples was detected by immunohistochemical staining.

RESULTSThe mean dCt value of Ang-2 mRNA expression in the cancer tissue was 6.86 +/- 1.37, significantly lower than that in the paired adjacent non-cancerous tissue (7.95 +/- 2.08, P < 0.05), indicating a significantly higher expression of Ang-2 mRNA in the cancerous tissue than that in the adjacent non-cancerous tissue. The distribution of Ang-2 protein was found not only in the vascular endothelial cells but also in tumor cells. Semi-quantitative analysis revealed that the expression of Ang-2 protein in tumor specimens (53.6%) was significantly higher than that (24.0%) in the paired adjacent non-cancerous tissue (P < 0.05), the result was well consistent with that measured by RT-PCR. The dCt value of Ang-2 mRNA expression was 6.48 +/- 1.16 in the patients with metastasis in lymph nodes versus 7.16 +/- 1.49 in those without, with a non-significant difference between the two groups (P > 0.05). As regards the clinical stages, no significant difference was found between the expressions of Ang-2 mRNA in stage I + II (7.11 +/- 1.63) and stage III + IV cases (6.49 +/- 1.10, P > 0.05).

CONCLUSIONAngiopoietin-2 protein is expressed not only in vascular endothelial cells, but also in tumor cells, suggesting that angiopoietin-2 may take part in angiogenesis in oral squamous cell carcinoma. However, our results that high expression of angiopoietin-2 mRNA is not correlated with lymph node metastasis and clinical stages, needs to be further verified in a large scale study.