人脑星形细胞瘤组织中环氧化酶2的表达及其临床意义

Expression and clinical significance of cyclooxygenase-2 in human astrocytoma

目的通过检测环氧化酶-1(COX-1)和环氧化酶-2(COX-2)在人脑星形细胞瘤、正常脑组织中的表达,探讨COX在人脑星形细胞瘤发生发展中的作用.方法应用逆转录聚合酶链反应(RT-PCR)和免疫组化SP法检测人脑星形细胞瘤、正常脑组织中COX-1,COX-2mRNA和蛋白的表达及其与肿瘤恶性程度、病理级别的关系.结果RT-PCR检测20例人脑星形细胞瘤组织COX-2mRNA均阳性表达,正常脑组织中未见表达,两者有显著性差异(P<0.0001);COX-1mRNA在20例肿瘤标本及正常脑组织中均有结构性表达.50例人脑星形细胞瘤标本免疫组化显示COX-2蛋白主要集中在肿瘤细胞胞浆内,阳性表达率为72%,正常脑组织未见阳性表达;而COX-1蛋白主要表达在正常脑组织中,肿瘤组织中为阴性表达.COX-2蛋白阳性表达强度与肿瘤病理级别有关,恶性程度较高的Ⅲ,Ⅳ级星形细胞瘤高于恶性程度较低的Ⅰ,Ⅱ级星形细胞瘤.结论COX-2mRNA及其蛋白在人脑星形细胞瘤组织中阳性表达且与肿瘤病理级别相关,说明COX-2可能在人脑星形细胞瘤的发生发展中起重要作用.

AIM： To investigate the role of cyclooxygenase （COX） in the development and progression of human astrocytomas through examining the expressions of COX-1 and COX-2 in human astrocytoma tissue and normal brain tissue. METHODS： Reverse transcriptase-polymerase chain reaction （ RT-PCR ） and immunohistochemistry（SP） were applied to detect the mRNA and protein expressions of COX-1 and COX-2 in human astrocytoma tissue and normal brain tissue. Furthemore the relationship between COX expression levels and cancer pathological grades was analyzed. RESULTS： Using RT-PCR, all 20 fresh specimens from human astrocytomas were shown to express COX-2 mRNA, while no positive expression of COX-2 mRNA was found in 8 specimens of normal brain tissues ; there was a significant difference between the two （P 〈 0. 0001 ）. But COX-1 mRNA was expressed constitutionally in all 20 of the fresh cancer tissues and 8 samples of normal brain tissues. The immunohistochemical result showed that COX-2 protein was mainly localized at cytoplasm of malignant cells（ positive rate was 72% ）, but was not expressed in normal brain tissues. In contrast, COX-1 protein was mainly localized at brain cells in normal brain tissue （positive rate 100% ）, but was not expressed in human astrocytomas. In 50 paraffin embedded specimens of human astrocytomas, the intensity of COX-2 expression was associated with tumor grade and stage. The level of COX-2 expression was higher in grade Ⅲ , Ⅳ tumors than in grade Ⅰ , Ⅱ tumors. CONCLUSION： The expression of COX-2 mRNA and protein is enhanced in human astrocytomas and is associated with malignant degree of the tumor, indicating that COX-2 may play an important role in the development and progression of human astrocytomas.