| ObjectiveuPA and PAI -1 are important co - regulators of Plasminogen activated system and closely related to tumor behavior. The purpose of this study was to examine the expression of uPA and PAI - 1 in primary and recurrent astrocytic tumors and to investigate the relationships among expression of these Plasminogen activation system regulators and tumor histopathologic grades and recurrence of astrocytic tumor .MethodsPatient selectionTissue samples of primary astrocytic tumors (n = 14) and non - tumor brain tissues ( n = 8) were obtained from patients who underwent surgery in the Second affiliated hospital of China Medical University between April, 1999 and March, 2002. Tissue samples of primary and recurrent astrocytic tumors ( n = 15) were obtained from patients who underwent surgery in the Firstly affiliated hospital of China Medical University between April, 1999 and March, 2002. All tumors were graded according to World Health Organization criteria ( WHO grade 1 n = 9, grade 2 n = 9, grade 3 n = 11, grade 4 n = 15 ).ImmunohistochemistryA total of 52 formalin - fixed and paraffin - embedded specimens was available for this study. Expression of uPA and PAI - 1 protein was immunohisto-chemically investigated. Paraffin sections were cut at a 5 - m thickness, depar-affinized with xylene and rehydrated. After endogenous peroxidase activity was blocked with 0. 3% H2O2 for 10 min at room temperature, the sections weretreated with 0.1 mol/liter citrate ( pH 6.0) in a 500 - W microwave oven for 10 min for antigen retrieval. After blocking nonspecific reactivity with normal non-immunone serum for 10 min at room temperature, the sections were incubated with anti - uPA E and anti - PAI -1 monoclonal antibody for one night at 4^C thermostat and then with biotin - conjugated second antibody for an additional 10 min at 37 C. Positive signals were detected by the S - P method with UltraSensi-tive鈩?S - P kit. Sections were also counterstained with hematoxylin. The labeling indexs of uPA and PAI - 1 were calculated microscopically field at a magnification of 400 by counting at least 500 tumor cells from selected fields. Strong reactions in the cytoplasm were considered positive for both uPA and PAI -1.Statistical methodsx2 test was used to compare the expression of uPA and PAI - 1 in astrocytic tumors and non - tumor brain tissues. x2R C contingency table were used to assess the relatio between the histopathologic grades of tumor, uPA and PAI -1. X2 test of paired comparison of enumeration data was used to compare the expression of uPA and PAI - 1 in primary and recurrent astrocytic tumors. Non-parametric Spearman rank correlation coefficients were used to assess the degree of association between uPA and PAI - 1 . Statistical significance was defined as p 0.05.ResultsTissue samples of normol brain tissues (n = 8 ) were negative for both uPA and PAI -1. All of the 44 astrocytic tumors' s specimens studied were positive for both uPA and PAI - 1. The positive rate of uPA was 81. 8% , the positive rate of PAI - 1 was 72.7%. The expression of uPA and PAI - 1 has a significant difference between normol brain tissues, low - grade astrocytic tumors and high- grade astrocytic tumors ( p < 0. 05 ). We also analyzed the relationships between the histopathologic grades of tumor, expression intensity of uPA and PAI- 1. The uPA tended to increase with tumor grade ( x2 = 33. 374, P < 0.05) and the PAI - 1 tended to increase with tumor grade ( x2 =24. 2088, P < 0. 05 ). There was a strongly plsitive correlation between uPA and PAI -1 ( r =0.886,p< 0.01).The positive rate of uPA was 73.33% in the 15 primary astrocytic tumors, the positive rate of PAI - 1 was 73. 33% in the 15 primary astrocytic tumors. The positive rate of uPA was 80% in the 15 recurrent astrocytic tumors, the positive rate of PAI - 1 was 73. 33% in the 15 recurrent astrocytic tumors(p > 0. 05 ). The expression intensity of uPA and PAI -1 tended to increase with tumor s recurrence( PuPA > 0.05, PPAI - 1 < 0.05 ).There ha... |
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