The Expression And Distribution Of TP In Human Gliomas And Its Clinical Significance

BACKGRAND AND OBJECTIVE:Angiogenesis has been well known to be a factor related to the tumor growth and prognosis .Recent studies have reported that thymidine phosphorylase(TP) is identical with platelet-derived endothelial cell growth factor(PD-ECGF). It not only plays an important role in the induction of tumor angiogenesis, but also enhances the chemotherapeutical sensitivity of the tumor cells to prodrug of fluorouracil. However, until now, the complete indentity of view about the function of TP expression in the human glioma and its clinical significance has not been reached. The present study was to explore the TP expression levels and its irnrnunohistochemical localization in a series of 58 human gliomas, and we correlated its expression with tumor angiogenesis and its clinical significance. MATERIALS AND METHODS:1: Specimans: From September, 1994 to Augest,1999, 58 surgical specimans were obtained from patients with glioma, included 32 males and26 females, ranging in age from 21 to 75 years(mean 57.5).There were 22 low grading and 36 high grading gliomas ,diagnoised according to WHO classification. All tumors were located in superior of tentorium,and those in basilar ganglion, brainstem or hypothalamas were excluded. Each patients recieved routine postoperative irradiation and chemotherapy. Additional 8 cases normal brain tissues were obtained from brain injury, and specimens were fixed with 4% paraform and embedded in paraffin. ALL the specimens were routine serial section,whose thickness was 4um.2. Main agentsThe main agents supplied by Zhongshang Beijing Biotech Incompany. Including: rat-anti-TP monoclonal antibody, rat-anti-CD68 monoclonal antibody, rat-anti-CD34 monoclonal antibody, S-P agent box and DAB agent,et.3.Methods:3.1 HE staining: All the sections were performed HE staining to certify the diognosis.3.2 All the sections of 66 specimans were immunohistochemically stained for TP, CD68(a macrophage marker) and CD34(an endothelial cell marker). To confirm the identical distribution of TP positive cells,a double staining for TP and CD68 in 8 glioma cases was performed.3.3 Control group: every time,PBS substituted tumor tissue specimen of first antibody used as negative control, and sections of breast carcinoma,rectal cancer and esophageal carcinoma used respectively as positive control of TP,CD68 and CD34.4. Result determinant4.1 Determinant of TP expression : Acording to staining intensity and the total area of staining cells,scores of staining intensity: no staining =O,slight stining(light yellow)=l,middle staining(brown)=2,strong staining(dark brown)=3; Scores of staining area:no staining=O,staining of less than 25%cells =1, staining of 25% to 50% cells =2, staining of more than 50%cells =3, If the two kind of scores is add up to >2,it refers to positive TP expression ,if ^=2, it refers to negative expression.4.2 Determinant of CD68 expression: According to Leek method, choose three areas with the most positive cells in each section,then count them under high microscopy (x200) respectively. The mean value is the CD68 expression of the tumor.4.3 Determinant of MVD: Evaluate the MVD of the tumor according to Weidner method, selecting three hot points under low microscopy , then turning to high microscopy (x200), the mean value of the three fields is MVD of the tumor.5. Statistical analysisTP positive or negative is numeration data, the value of CD68+ cell and MVD are measurement data, x2 test is to analysis the relationship of two numeration data, and T test is for measurement data. The relative coefficient adopts pearson coefficient, analysis of life span use Kaplan-Meier method and log-rank test. All data statistics were completed in the SPSS 12.0 statistical package. RESULTS:1. TP, CD68 or CD34 expression in glioma are all obviously enhanced, and there are significant difference between low and high grading tumors.Double labeling for TP and CD68 indicated that the majority of TP positive cells are macrophages, located in tumor infiltrating fields and necrotic tissues or around cancer nests.2. Both TP and CD68 expression levels were correlated with intratumoral microvessel density positively. TP and MVD associated with tumor s pathology grade and prognosis, however, the level of macrophages is only related to malignancy grading. Only MVD could be received as independent prognostic factor for glioma patient. CONCLUSIONS:These findings suggest that TP might play a crucial role in angiogenesis during glioma development. TP detection in glioma patients might served as an useful parameter for clinical prediction and designing therapeutic schedule. Further studies are necessary to elucidate the role of TP in glioma, which may provide insights into measurable TP-targeted therapy.