Immunohistochemical Expression Of COX-2and Clinical Implication In Hypopharyngeal Squamous Cell Carcinoma

ObjectiveHypopharyngeal squamous cell carcinoma, a malignant neoplasm arising from the mucosa of the upper aerodigestive tract, is one of the most aggressive cancers in the head and neck area. Our aim is to evaluate the expression levels of COX-2in hypopharyngeal squamous cell carcinoma, and to examine relationship with tumor invasion and lymph node metastasis. Furthermore, we analyze the correlation among them and figure out if COX-2can be indicated the tumor invasion and lymph node metastasis.Methods101cases of surgically excised primary tumor were included in this study. The carcinoma tissues were obtained intra-operatively from patients who were operated in the hospital during January2004to May2011. Meanwhile,40tissues of epithelium adjacent to carcinoma were used for comparison. Immunohistochemical methods were used to detected the expression of COX-2in these tissue. The immunostaining densities of COX-2in hypopharyngeal carcinoma were quantitatively assessed with the Image-pro plus6.0. The mean optical density (OD) of the positive areas was measured. The results were expressed as the exact value of the relative optical density units. The SPSS software (version17.0) was used in this study.ResultIn this study, diffuse cytoplasmic staining for COX-2appeared in almost all carcinoma tissues and70.0%of adjacent normal epithelium tissues. However, normal epithelium presented weaker COX-2staining. COX-2expressed in carcinoma tissues was significantly higher than that in adjacent normal tissues (t=9.004, P<0.001) Moreover, increased COX-2expression was strongly associated with lymph node metastasis (t=-l0.559, P<0.001), T classification (t=-4.085, P<0.001) and clinical stage (t=-5.428, P<0.001). No correlation was found between COX-2and histological grades (t=0.046, P=0.956). Survival analysis showed survival time is significantly correlated with≥P50level of COX-2expression,≥P75level of COX-2expression,≥P85level of COX-2expression and≥P90level of COX-2expression (P<0.05). Univariate and multivariate Cox’s proportional hazard model analysis indicates that recurrence and>P50level of COX-2expression had an independent prognostic effect on prognosis (P<0.05). Neither clinical stages nor node metastasis had any significant association with survival.Conclusion:1. COX-2expressed in hypopharyngeal squamous cell carcinoma tissues was significantly higher than that in adjacent normal tissues. This suggests the relationship between the overexpression of COX-2and hypopharyngeal squamous cell carcinoma.2. Increased COX-2expression was strongly associated with lymph node metastasis, T classification and clinical stage. No correlation was found between COX-2and histological grades. This indicates that COX-2overexpression may be associated with tumor invasion and lymph node metastasis.3. Survival analysis showed survival time is significantly correlated with of COX-2overexpression, and suggests that the relationship between the level of COX-2and prognosis.4. We test the level of COX-2in hypopharyngeal squamous cell carcinoma to reflect the correlation between the tumor invasion, lymph node metastasis and prognosis which provides us with a novel way to predict the progression and prognosis of the tumor.