| BACKGROUDMeningiomas are common among intracranial tumors, estimate to account for 13% to 19% of all primary brain tumors. In general, they are slow-growing tumors with benign behavior. Along with the recent 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 ). The risk of recurrence and aggressiveness of the different histologic types of meningiomas are associated with their histologic grades. The apparant pathogenesis of meningiomas is still unclear, may be related to changes of enviroment of body and gene mutation.The abnormality of cell cycle control is closed associated with the loss of control of cell proliferation. In the celluar program leading to DMA synthesis, signals that drive cells into S-phaseconverge at the level of CDK activity. The products of at least three different genes families: Ink4, Cip/Kip and the pRb pocket-protein familiy, suppress S-phase entry. p21 and p27 are two members of cyclin-dependent kinase inhibitor. Expression of p21 is induced by wild-type p53 in response to DNA damage. By inhibiting CDKs, they modulate the cell cycle by interrupting the transmission from Gi to S phase in the cell cycle. However, p21 protein expression varies in different human malignanies, and the clinical significance of p21 expression in tumors is still unclear. p27 has been showed antitumoral properties and is a clinical marker in tumor progression. It has been reported that its loss represents a negative prognosis. Few have reported the p21 and p27 expression in meningiomas. Many previous studies on the p21 protein expression in meniniomas have shown significant correlation with the histological grades of meningiomas, and p27 expression has been reported to show an inverse correlation with the histological grades of meningiomas. We carried out immunohistochemical study of the meningiomas for the expression of p21 and p27 preteins expression and correlated their relationship with histological grades.MATERRIALS AND METHODSHistologic sections of meningiomas resected through 2001 were retrieved from the archives of the Department of Pathology of SIR RUN RUN SHAW Hospital. 39 cases were regrouped as benign and atypical and anaplastic(malignant) by H.E staining accordingto the recently published WHO classification of the tumors of nervous system. We carried out immunohistochemistry and detected the expression of p21 and p27, the concentration of primary antibody is l:100.The labeling index (U) defined as the percent of positive staining cells for each case was determined by counting 1000 tumor cells. According to the LI of the tumor cells, the staining cells were devided as negative by the LI below 5%, mild positive by 5% to 25%, moderate positive by 25% to 50% and strong positive by the LI beyond 50%. The comparisions of the expressions of p21 and p27 were analyzed by SPSS.RESULTp21 expression was seen in 28/39 cases (71.8%) , and the average LI was 40. 26?5.39%. p21 expression was higher in meningiomas of grade Hand 111(100%) than that in meningiomas of grade I (67.7%), and the difference was significant (P<0.05). p21 expression was no correlation with sex, age of patients and tumor size(P>0.05). The LI of p21 expression in meningiomas of grade I (15.38 ?6.57%) was lower than in meningiomas of gradeIIand III (63.92?18.93%), and very statistically significant correlation was found between p21 expression and histological types and grades of meningiomas(P<0.01).p27 expression was seen in 34/39 cases (87.2%) , and the average LI was 21.6?3.38%. The average LJ of p27 expression in meningiomas of grade II and 111(33.60%) is Ipwer than that in meningiomas of grade I (41.24%), but the difference was nostatistically significant (P>0.05). p21 expression was also no significant difference with sex, age, tumor size of meningiomas (P>0.05).In present study there was no significant (difference between p21 and p27 expression(P>0.05).CONCLUSIONS1. p2...
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