| IntroductionPituitary adenoma is one of the most common intracranial benign tumors, which rankS third in intracranial tumors with the incidence rate about 1/100000-7/100000. Pituitary adenomas are more frequent at age between 20 and 50 and they affect both sexes equally.In fact, pituitary adenoma is an incidental finding in about 20% to 25% of all glands studied in large autopsy leseries. Pituitary adenomas, with characteristics of localized growth and without metastasis, have good prognosis after operation. But some pituitary adenomas with invasive behavior would lead to postoperative recurrence, which invaded bone, dura, nerves, cavernous sinus and blood vessels widely and couldn't be removed completely. The therapy effect is relative to the invasiveness of pituitary adenoma. Tumor cells lose contact inhibition, dephlogisticated air and nutrient are offered by angiogenesis and tumor cells degrade extracellular matrix and destroy basement membrane. Matrix metalloproteinase (MMPs) and nitric oxide synthase play an important role in it.Matrix metalloproteinases are a family of enzymes whose main function is degrading of the extracellular matrix.MMPs have been defined functionally as having the following characteristics (1) they are proteinases which degrade at least one component of the extracellular matrix; (2) they contain a zinc ion and are inhibited by chelating agents (3) they are secreted in a latent form,requiring activation forproteolytic activity;(4) they are inhibited by tissue inhibitors of metalloproteinases (TIMPs);and (5) they share common amino acid sequences.MMP-2 (gelatinase A) and MMP-9 (gelatinase B) are the main matrix metalloproteinases in decomposing collagen including type IV and V in the matrix, because collagen IV not only exists in the ECM, but also is one of the most important components of the basement membrane. Besides the structure proximity between MMP-2 and MMP-9 gene, the latter has a specific sequence of 48 bases which cannot be found in other MMPs, and this discrepancy may lead to the different expression in pituitary adenoma tissue. Matrix metalloproteinases can degrade extracellular matrix and destroy basement membrane to accelerate angiogenesis of tumors.Nitric oxide(NO) is a kind of simple but important signal molecule functioning as a kind of second messenger and taking part in many physiological and pathological processes including tumor.Endogenous NO production depends on conversion of the amino acid L-arginine to L-citrulline by a family of enzymes named nitric oxide synthase(NOS).NOS has three isoforms: endothelial type NOS(eNOS),neuronal type NOS(nNOS) and inducible type NOS(iNOS).Research so far has proved that NOS exists in many kinds of tumor cells including cell of liver cancer, of breast cancer and of squamous cell carcinoma in head and neck. It is also reported that expression of NOS and its production NO have correlation to prognosis in certain malignant tumors. Angiogenesis existing in many tumor tissues and regarded as an inevitable phase in tumor progress is correlative to tumor growth, local invasion and metastasis. NO plays an important role in angiogenesis of pituitary adenoma.In this research,we detected the expressions of MMP2JMMP9, iNOS,nNOS and microvessel density(MVD) in pituitary adenoma tissues .This will help us to realize the correlation between MMPs(MMP2,MMP9),NOS(iNOS,nNOS) and MVD and its relation with the invasiveness of pituitary adenoma.Materials and Methods1. 33 cases specimens of pituitary adenomas, 23 cases of them are invasive pituitaryadenoma, 10 cases are non-invasive pituitary adenomas.2. Using immunohistochemical SP staining, We detected MVD(labeled by CD34), MMP2,MMP9,nNOS,iNOS in paraffin slices of 33 pituitary adenoma tissues.3. Relationships between MMP2, MMP9, nNOS, iNOS expression and MVD were analyzed in pituitary adenoma tissues, and so were relationships between MMP2, MMP9, nNOS,iNOS expression,MVD and invasiveness of pituitary adenoma.ResultsThere is no significant difference in age... |
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