Cyclin D2在人脑胶质瘤的亚细胞表达及意义

目的研究细胞周期素D2(cyclin D2)在人脑胶质瘤中的亚细胞表达.方法采用免疫组化方法检测52例人脑胶质瘤及8例正常人脑组织中cyclin D2蛋白和增殖细胞核抗原(PCNA)的表达.结果正常人脑组织中无cyclin D2表达,而在胶质瘤细胞胞核和胞浆中均发现cyclin D2的阳性表达,并随肿瘤恶性程度增高而表达增强.其中11例(21.2%)出现胞核染色,高恶性度胶质瘤(Ⅲ～Ⅳ级)与低度恶性胶质瘤(Ⅰ～Ⅱ级)标记指数与阳性率无显著性差异(P＞0.05);胞浆染色阳性率为42.3%(22/52),低、高恶性度组标记指数间差异显著(P＜0.05),各相邻级别之间无显著差异(P＞0.05).二元相关性检验显示cyclin D2胞浆染色标记指数与PCNA标记指数呈正性相关(r=0.478,P＜0.01).结论人脑胶质瘤细胞胞核和胞浆中均存在cyclin D2的表达,其中胞浆表达与肿瘤细胞的增殖活性密切相关,提示其可能在肿瘤细胞细胞质中发挥重要正性调控作用.

Subcellular distribution of cyclin D2 in human gliomas and its significance

Objective To investigate the expression and intracellular location of cyclin D2 protein in human brain gliomas. Methods Immunohistochemistry was used to investigate the expressions of cyclin D2 and of PCNA in 52 glioma cases and other 8 cases of normal brain tissues. Results Positive staining signals were absent in normal brain tissues, but were detected in nuclei and/or cytoplasm in human glioma cells, which increased with advancing of pathological grades. Positive nuclear staining was observed in 11(21.2%) cases, but significant difference was not found between different grades. Positive cytoplasmic staining was found in 22(42.3%) out of 52 glioma cases, and labeling indices were significantly higher in high grades than in low grades( P <0.05). No remarkable difference was seen between adjacent grades ( P >0.05). Bivariate correlation analysis revealed a positive correlation between cytoplasmic staining LI label index and PCNA LI( r =0.478, P <0.01). Conclusion Besides its normal expression in glioma nucleus, cyclin D2 is expressed in cytoplasm as well, which is closely correlated with the proliferation activities of tumor cells. This implies its important role of regulating cell cycle in tumor cytoplasm.