Expression And Significance Of Cyclin A And Cathepsin D In Meningiomas

Meningioma is a common intracranial neoplasm arising from the arachnordal layer covering over the brain. It is estimated that meningioma account for 13-26 percentage of all central nerve system tumors. The apparent pathogenesis of meningioma is still unclear. In general, they are slow-growing tumors with benign behavior, but about 3 percentage of meningiomas with malignant behavior, fast-growing and recurrent after operation. Along with the classification of the tumors of nervous system adopted by WHO, there are three types of meningiomas, benign (grade I), atypical (grade II) and anaplastic (malignant) (grade III). It is limited to predict behavior of meningiomas only dependent on histological features such as loss of architectural pattern, necrosis, nuclear pleomorphism. Resently, some antigen such asprogesterone-receptor, bromodeoxyuridine (BrdU), MIB/Ki-67 is used to provide information for prognosis of meningiomas.The abnormality of cell cycle control is a complicated course which is controlled by a series of protein composed with cyclin and cyclin dependent kinase (CDK). Cyclin A is a cell cycle regulatory protein with 60 kilodaltons. In S phase, cyclin A binds to CDK2, which is necessary for effective DNA duplicate. Cyclin A iscorrelation with transcript factor such as pl07,pl30 and E2F. It was reported deranged expression of cyclin A in carcinoma.Cathepsin D is an aspartyl endoproteinase, which has been assumed to degrade components of the basement membrane in tumors, facilitating the development of metastasis and tumor infiltration.We determined immunohistochemical expression of cyclin A, cathepsin D and Ki-67 in meningioma of 41 cases and their relationship with histological grades.MATERIALS AND METHODSHistological sections of meningiomas resected in 2001-2004 were retrieved from the archives of the Department of Pathology of SIR RUN RUN SHAW Hospital. 41 cases were regrouped as benign , atypical and anaplastic (malignant) by H.E staining according to the recently published WHO classification of the nervous system tumors. We carried out immunohistochemistry and detected the expression of cyclin A ,cathepsin D and Ki-67.The labeling index (LI) defined as the percent of positive staining cells for each case was determined by counting 1000 tumor cells. The result of the expressions of cyclin A and cathepsin D were analyzed by STATVIEW.RESULTCyclin A immunostaining is nuclear-staining, cyclin A labeling indices don't correlate with sex, age of patients and tumor size (P>0.05). But there is statistically significance between cyclin A labeling indices and WHO grades of meningiomas(P<0.0001).Cathepsin D immunostaining is cytoplastmic-staining. There were 29 cases that cathepsin D labeling indices more than 50% in all 35 cases grade I meningioma. However. There was only 1 case cathepsin D labeling indices more than 50% in all 6 cases of grade II and III meningiomas. But there is no significance (P>0.05). Cathepsin D expression had no correlation with sex, age of patients and tumor size(P>0.05). Ki-67 expression was found in 40 of 41 cases. Ki-67 labeling indices had no correlation with sex, age of patients and tumor size(P>0.05). But it had marked statistically significance between Ki-67 labeling indices and grades of meningiomas(P<0.0001).CONCLUSIONSThe result above demonstrates that cyclin A and Ki-67 is a useful marker predicting behavior of meningioma, cathepsin D is not useful as a prognostic marker in meningioma in our research. Significance of cathepsin D need advance research.