Expression Of BNIP3 And Its Prognostic Value In Human Medulloblastoma

Objective: BNIP3 is cloned from human fetal liver library and the genes have antitumor activity, it has been reported that BNIP3 has abnormal expression in the variety of human tumor tissues. In recent years, BNIP3 and tumor-related research has become a new hot spot in the basic cancer research , but there have not reported about BNIP3 in the human medulloblastoma research in the literature at home and abroad. In this study, we detected the expression of BNIP3 in medulloblastoma by immunohistochemistry method, and explored its relationship between the prognosis in patients who have medulloblastoma.Methods: (1) Selected 30 medulloblastoma cases from January 2001 to January 2008,the specimens achieved from Anhui Medical University Neurosurgical operation(operative deaths excluded), 10 cases of normal cerebellar tissue specimens resection from the brain trauma decompression surgery. In the 30 cases of medulloblastoma, male 22 cases, 8 female, the ratio of male to female is 2.75:1, age 3-34 years, mean 13.4 years of age. All patients were receiving postoperative radiotherapy for the whole skull and spinal canal, some patients undergoing chemotherapy.(2) All of this group, 30 patients were followed up through out-patient letters, phone calls, etc. Survival period is from diagnosis to establish the date, termination date is the date of death or final follow-up date, all patients were followed up ,and the deadline date is January 2009.(3) using immunohistochemical S-P method. HIF-1αpolyclonal antibody and BNIP3 monoclonal antibodies were purchased from Wuhan Boster Biological Engineering Co., Ltd.SP immunohistochemistry kit and DAB reagent were purchased from Beijing Zhong Shan Golden Bridge Biotechnology Co., Ltd. The working concentration of BNIP3 and HIF-1αwere 1:100, Specific stained operations according to the manual steps. microwave repair antigen, use PBS instead of primary antibody as negative control.(4) To find the yellow, brown yellow or brown particles appears in the cytoplasm and (or) the nucleus as positive cells , randomly observed five high power fields in per slice, count positive cell in the 100 cells of each field of vision, take the mean, calculate the average percentage of the stain effect, greater or equal 10% was positive expression, less 10% was negative.(5) using SPSS 13.0 statistical software for data processing, respectively using chi-square test, Fisher exact test, Spearman correlation analysis, Kaplan-Meier survival analysis, Cox proportional hazard regression model and other statistical methods for statistical analysis.We done the univariate COX regression analysis firstly, the factors P less than 0.20 as statistically significant variables, put the significant variable to single-factor into the multi-factor models at last, using the method of multiple COX regression analysis to stepwisely regression analysed.Results:(1) 30 cases of medulloblastoma samples, 19 cases of the expression of BNIP3 was positive, positive expression rate was 63.3%, mainly expressed in the nucleus and also express in the part of the cytoplasm, expression products was the brown color reaction product, positive expression of the tumor is more prominent around the necrotic area; 17 cases of HIF-1αexpression was positive, positive expression rate was 56.7%, expressed both in the nucleus and also express in the cytoplasm, xpression products was the brown color reaction product, BNIP3 and HIF-1αboth no expression in the normal tissues of the cerebellum (Figure 1-4). the difference expression of BNIP3 and HIF-1α in medulloblastoma and normal cerebellum tissue was significant (P <0.01), at the same time, the difference expression of BNIP3 and HIF-1αin medulloblastoma tissues were positively correlated (r = 0.451, P = 0.012).(2) Kaplan-Meier survival analysis showed that expression of BNIP3 in the positive group is poor to compared with the negative group in the cumulative survival difference, log-rank test (Log-rank test), X2 = 12.60, P = 0.000.(3) According to the ratio of various factor of the Cox proportional hazard model, the factors of gender, age, tumor size, tumor location, conditions associated with hydrocephalus, the invasion of brain stem, tumor resection rate and BNIP3 as a variable. Using univariate COX regression analysis , P less than 0.20 as statistically significant factor in the variable and finally the single-factor significant variables (age, tumor resection rate, BNIP3) into the multi-factor models.The methods is stepwise multiple regression analysis regression analysis of COX . The results showed that independent prognostic factors BNIP3 (P <0.01), the odds ratio (OR) of 5.350, OR values greater than 1, suggesting that BNIP3 is an independent risk factor.Conclusions:(1) The high expression of BNIP3 may play an important role in the medulloblastoma's occurrence and development .(2) BNIP3's expression can be used as an indicator to determine prognosis of the medulloblastoma.(3) BNIP3 is expected to become a new molecular target in the medulloblastoma's gene therapy.