Expression and significance of angiopoietin-2 and cyclin D1 in laryngeal squamous cell carcinoma and the correlation with prognosis

The aim of this study was to study the expression of angiopoietin-2 (Ang-2) and the cell cycle protein D1 (cyclin D1) in laryngeal squamous cell carcinoma (SCC), and its clinicopathological meaning. The expression of Ang-2 and cyclin D1 was analyzed in 116 cases of laryngeal SCC, five cases of atypical hyperplasia and five cases of vocal polyp tissues using the immunohistochemical streptavidin-perosidase (S-P) method. Ang-2 and cyclin D1 protein expression was not present in 5 cases of atypical hyperplasia or 5 cases of vocal cord polyps. However, the proportions of positive staining in well, moderately and poorly differentiated laryngeal SCC were 40, 66.7 and 100%, respectively, for Ang-2 and 50, 66.7, 100%, respectively, for cyclin D1, and were statistically significant (P<0.05). The expression of Ang-2 was positively correlated with cyclin D1 in the laryngeal SCC (r=0.5042; P<0.05). This showed that the tumor grading and cyclin D1 were independent factors affecting laryngeal SCC patient survival by the Cox regression model of risk factors proportion analysis. Ang-2 is synergistic with cyclin D1 in the development of laryngeal SCC. Ang-2 is associated with the metastasis of lymph nodes. Detection of both Ang-2 and cyclin D1 may possess clinical significance in evaluating the prognosis and guiding the clinical treatment of SCC.