| Department of oral histology & pathology, Stomatological College, the Fourth Military Medical University, xi'an, 710032The aim of present study is to explore the tumorgensis and occurrence of pleomorphic adenoma by analyzing the expression and distribution of cell cycle related gene, apoptosis related gene, DNA content and number of AgNOR. The author hopes that this thesis can offer some assistance and provide a reference for clinical research and prognosis for pleomorphic adenoma.1. Effects of cell cycle related gene Cyclin Dl and cdk4 expression in PA and MPACyclin Dl, a positive regulator, could combine and active CDK4/CDK6 complex. The complex phosphated Rb and freed E2F-1, E2F-1 could active expression of some gene and startup DNA replication, promote cells enter S phase from Gl phase. In this study, expression of Cyclin Dl and CDK4 were detected by using immunohistochemistry. The results showed that expression of Cyclin Dl and CDK4 were significant higher in MPA that in PA and N. Expression of Cyclin Dl and CDK4 were higher in PA than in N. So over expression of Cyclin Dl and5CDK4 shortened Gl phase and aroused excess proliferation, even malignant transformation. Therefore, Cyclin Dl and cdkd4 assisted the formation of PA and MPA. The staining and quantity of the two factors provided an immportant foundation for the study of the malignant transformation.2. The relationship between E2F-1 and PA/MPAIn Gl/S phase, E2F-1 could combine genes that regulate cell cycle, modulate DNA replication and cell proliferation. E2F-1 could promote cell cycle and inhibit cell cycle in different pathway. The author observed the expression of E2F-1 in PA and MPA. The results showed that E2F-1 expression was significant stronger in MPA than in PA. The mechanism was that E2F-1 combined the promoters of its target genes such as Cyclin Dl, CyclinE, c-myc, and actived them. So E2F-1 taked a part in the formation of PA and MPA. The effect of E2F-1 toward cell cycle in PA and MPA was inhibition, not activation,3. Alteration of P21WAF1/CIIM mRNA expression in PA and MPAp21wAFuap) was one of fa members Of cja family. It can regulate cell cyclethrough inhibiting Cyclin/CDK complex. Using in situ hybridization, We detected the P21WAFI/CIP1 mRNA expression in PA and MPA. The results showed that the postive signals of p21 mRNA was much weaker in MPA than PA. In normal cells, the staining of P21WAF1/CIPI mRNA was strong, and could regulate the cell cycle. In PA, the postive signals decreased. It could combine and inhibit the activity of CDKs and Cyclins. Therefore, It inhibited the progress of Gl phase. In MPA, p2jWAFi/cipi expression was much weaker, this weak expression maybe because of mutation, deletion of p21 genes and inhibition of opening expression. This illuminated that weakness or vanish of p21 expression might reduce the inhibition of p21 to cell cycle and contributed to the formation of MPA.4. Apoptosis related gene bcl-2 and apoptosis in the formation of PA and6Apoptosis was a programmed cell death in physical states, and was immportant in many diseases. Using in situ hybridization and TUNEL staining, We detected apoptosis related gene bcl-2 expression and the number of apoptosis cells, bcl-2 mRNA expressed in both PA and MPA. However, the expression in MPA was much higher than in PA. The number of apoptosis in MPA reduced significantly comparing with PA. There was a significant passive corrlation between bcl-2 and apoptosis index. So bcl-2 was closely related with the malignant transformation of PA. The mechanism was that bcl-2 gene blocked the apoptosis of tumor cells, the surviral stage of abnormal cells extended and tumor cells preliferated overdue and aroused the formation of tumors.5. Detection and analysis of DNA contents and AgNOR counting in PA and recrudescence casesDNA contents could reflect the degree of cell proliferation and chromosome abnormality. AgNOR was a regulator of DNA transcription. Changes of AgNOR could reflect the ability of cell differentiati...
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