The Expression And Significance Of Peroxisome Proliferator Activated Receptor-gamma In Pituitary Adenoma

Background:Pituitary adenoma is common benign carcinoma,the disease incidence of which is only lower than neurogliocytoma and meningeoma in cranial carcinoma.The attact rate of pituitary adenoma increases in recent years,which severely degrade the quality of life.Althouth surgery can cure about 60%-90% patients,there are still relapse rate of 7%-35%,especially for invasive pituitary adenoma.The relapse rate may be higher if the adenoma is excised completely.Except for some prolactinoma and GH adenoma can be treated by ergolactin,surgery assisted by radiosurgery is the primary treatment for most pituitary adenoma.There is no efficient drugs for unfunctional adenoma,ACTH adenoma and GH PRL adenoma which is no sensitive to drugs like ergolactin and GHRIH.In some cases radiosurgery is necessary if the adenoma is not excised entirely to prevent recurrence.Excessive excision of tumor and radioactive dose can do damage to anterior lobe of hyposis,resulting in hypopituitarism syndrome,hence the hormone replacement is forced to be carried out.PPAR is one of theⅡ-type nuclear receptor super family,functioned as regulatory factor in neclear transcription,includingα,β,γsub-type.In most cells,PPAR-α,PPAR-βand PPAR-γis expressed simultaneously,but in different levels.PPAR have complicated biologice function,taking part in the process of lipid metabolism,glycometabolism,adipocyte differentiation and energy balance,inflammatory reaction,arthrosclerosis,and tumor cell differentiation and necrosis.PPAR-γis studied intensivel,the main function of which is to promote the synthesis of lipid.More and more evidence indicate that the PPAR-γactivator has a distinguished function against tumor.The mechanism includes inhibiting cell multiplication,inducing cell apoptosis and differentiation,inhibiting angiogenesis and reduce the invasive ability of tumor.Objiect:In this case,with the method of immunohistochemistry,we study the difference of distribution and expressed level of PPAR-γ,in adenoma tissue in different groups(invasive group and non-invasive group,groups of different endocrine secretion),then explore the potention for clinical use.Material and methods:1.MaterialWe randomly select 86 samples gained through pituitary adenoma surgery in Shangdong Provincial Hospital since Jan 2006 to Oct 2007.46 samples is from male patients,and 40 from female,aging from 19 to 69.The average age is (39.3±1.4).There are 54 cases in invasive group,and 32 cases in non-invasive group.With regard to endocrine secretion difference,36 cases are PRL-type,13 cases are ACTH-type,25 are GH-type,4 cases are multiple secretion,8 cases are non-secretion type.All diagnosis is confirmed by immunohistochemistry methods.2.MethodsWe apply the SP method to examine the possitive ratio of PPAR-γexpression in pituitary adenoma sample in mineral wax,then compare the difference between groups using chi square test.Results:1.In the total 86 cases,54 cases are PPAR-γpositive,with positive ration 59.3% for men,and 58.3%for women,indicating there is no statistical difference between male and female.2.In the invasive group with 54 cases,40 cases are PPAR-γpositive(positive ration is 74.1%).While in the non-invasive group with 32 cases,11 cases are PPAR-γpositive(positive ration is 34.4%),indicating there is statistical difference between invasive and non-invasive pituitary adenoma(P＜0.05). In PRL-secretion group,20 cases are PPAR-γpositive of total 36 cases(55.6%).14 cases of total 25 cases are PPAR-γpositive in GH group(56%).12 cases of total 13 cases are PPAR-γpositive in ACTH group(92.3%).1 cases of total 4 cases are PPAR-γpositive in multiple secretion group(25%).4 cases of total 8 cases are PPAR-γpositive in non-functional group.There is statistical difference between ACTH and PRL group(P＜0.05),while no statistical difference between GH and PRL group(P＞0.05).Conclusion:1.The expression of PPAR-γin pituitary adenomas between sex does not exist significant difference.2.The expression of PPAR-γbetween the invasive and non-invasive pituitary adenomas there is a significant difference,suggesting that the invasive tumor and PPAR-γcorrelation between the potential clinical treatment guidance.3.The expression of PPAR-γbetween ACTH and PRL.GH pituitary adenomas are significant differences,but between the GH and PRL type does not exist the significant difference.This difference may indicate that the different expression of PPAR-γbetween different types of pituitary adenomas for the different reactions of the agonists Of PPAR-γ.