Expression Of COX-2,Ki-67 And VEGF In Bladder Transitional Epithelial Cancers And Their Significance

In recent years,lots of studies have been done on the role of Cyclooxygenase-2(COX-2) in neoplasms including bladder transitional cell carcinoma. But the results don't agree with each other.The current studdies suggest COX-2 is universally expressed in almost all kinds of tumors. Its relationship with tumor invasion and metastasis were extensively studied in several aspects. This review covered the following aspects to interprete the expression of COX-2 and tumor invasion and metastasis: COX-2 could modulate tumor cell apoptosis and its expression might facilitate tumor angiogenesis, therefore provides nutrients supply for tumor growth.Cyclooxygenase is a rate limiting key enzyme for transformation of arachidic acid into prostaglandins E₂. Cyclooxygenase has two kinds of isoenymes: Cyclooxygenase-1(COX-1) and COX-2. COX-1 is a constitutive gene. COX-1 protein is stable expressed in the normal tissue and normal cells. COX-1 catalizes to produce prostaglandin which maintains normal physiological fuction of the organism. COX-2 is a induciable gene. COX-2 is not detected in the normal physiological condition. But once it is stimulated by some inducing factors COX-2 will be denove synthesis qickly and participate in a lot of pathological and physiological process including the occurrence and development of the inflammation and tumor.The expression of COX-2 , Ki-67 , and VEGF was examined in 50 cases of bladder transitional cell carcinoma and 10 normal bladder mucosas by means of immunohistochemical PowerVision(PV) technique. The results of immunohistochemical staining were categorized into three grades including (-) (+)and (++). The correlations between the expression results and tumor pathological grades, clinical stages, number of lessions were studied.The result suggests that the expression of COX-2 in BTCCs was higher than that in normal bladder mucosas. The positive rate of COX-2 was 80% in BTCCs while it was not detected in normal bladder mucosas. Furthermore, its expression increased with the advance of tumor grade and tumor stage. COX-2 was highly positively related to the grade,stage and prognosis of tumors. The expression of COX-2 in poorly differentiated, invasive or recurring BTCCs was higher than that in well differentiated superficial or nonrecurring ones. But there was not significantly difference between the solitary tumous and multiple ones.The positive rat of Ki-67 was higher in TCC patients(74%) than in the mormal mucosas(10%). Its expression increased with the advance of guade and stage. Its expression had negative correlation with grade ane stage. The expression in recurring and multiple tumous was higher than that in nourecurring and solitary ones.There was no case that observed positive expression of VEGF in 10 case of normal mucosas, while the positive rate of VEGF in TCC was 80%. And its expression level elevated with the advance of grade and stage, there was statistical significance. The recurrent tumor group had a higher expression level of VEGF than primary tumor group.There were positive correlation both between COX-2 and Ki-67 and between COX-2 and VEGF. There was positive correlation between Ki-67 and VEGF too.This result suggests that the high expression of COX-2 may have great significance in the development and growth of bladder cancer. The expression ofCOX-2 is related to the pathological grades, clinical stage, and recurring of tumor. The high expression of COX-2 may benefit increase in bladder cancer cell prolife-rative activety. VEGF expression in COX-2 positive tumor was significantly higher than that COX-2 negative tumor.The expressions of VEGF and COX-2 are positively correlated with each other,which indicates that COX-2 may induce the expression of VEGF.