| Two major classes of genes critical for the development of all types of cancer are now recognized: tumor suppressor genes, which encode genes that function to inhibit cell proliferation and tumor development, and oncogenes, which encode proteins that stimulate proliferation and mediate biological activities important for invasion, neoangiogenesis, immune escape, and other characteristics of malignancy. The activation of cellular oncogenes and inactivation of tumor suppressor genes represent important genetic alterations leading to progressive disorder of normal cellular growth control mechanisms. This has engendered substantial efforts to elucidate the molecular genetic and biologic basis of glioma formation. Malignant gliomas are the most common primary tumors of the central nervous system, and astrocytomas are the most common tumors of the gliomas. In recent years, there have been great advances in our understanding of the genetic events and the molecular biology of human brain gliomas. According to the discoveries of the genetic aberrations that occur during the progression of gliomas, the occurrence of a malignant tumour cell is the result of a multistage process. Molecular studies provide an insight into the pathogenesis of brain tumour development. However, they may also have an effect on developing new forms of tumour-specific therapy. Survivin is a new anti-apoptosis gene which was discovered recently, and survivin protein is a new member of inhibition of apoptosis protein (IAP) family. It caninhibit cell apoptosis, and play a significant role in cell mitosis and cytoplastic cleavage. Study shows survivin is a tumor specific anti-apoptosis gene, and it is thought to be an oncogene, which is expressed during the fetal development and in common human tumors, but cannot be found in normal adult tissues. Survivin expression is considered to be an important prognostic factor for many tumors. P53 is a tumor suppressor gene, which can block cells progression and/or induce apoptosis during the cell cycle. Mutation or deletion of p53 is frequently found in a variety of human cancers. Human gliomas are highly invasive tumor, which remain to be a major obstacle for effective therapeutic remedy. The mechanisms of genetic change of astrocytic tumors have not been understood completely. Research of survivin expression in gliomas, the role of it in gliomas' growth and invasion, and the relationship between survivin and p53 in gliomas, is started recently abroad, and cannot be found domestically. OBJECTIVEThe main aim was to discuss the function of survivin in astrocytoma occurrence and evolution, and its relation to p53. Through the study of survivin and p53 expression in astrocytoma and their relationship, we analyzed the molecular mechanisms of survivin and p53 during oncogenesis. It might be a valuable target for early diagnosis and therapy of astrocytoma, and could provide a new target gene for effectual remedy to astrocytoma. METHODSThe positive rates of survivin and p53 expression in 10 cases of normal brain tissue, 18 cases of astrocytoma grade â… , 20 cases of astrocytoma grade â…¡, and 27 cases of astrocytoma grade â…¢-â…£ were studied by immunohistochemistry. RESULTS1. The positive rates of survivin expression in astrocytoma were higher than that in normal brain tissues, they were 0.0%(0/10) and 49.2%(32/65) respectively, when compared with each other, there exsited statistical significance(P=0.004). From astrocytoma of grade â… , astrocytoma of grade â…¡ to astrocytoma of grade â…¢-â…£, survivin positive expression raised gradually, the positive rates were 11.1%(2/18), 40.0%(8/20) and 81.5%(22/27), and the resultswere of statistical significance(P=0.000). The difference between astrocytoma of grade â… and astrocytoma of grade â…¡ was of statistical significance(P=0.043). There also existed difference between astrocytoma of grade â…¡ and astrocytoma of grade â…¢-â…£, and the difference was of statistical significance (P=0.003).2. The positive rates of p53 also raised from normal brain ti...
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