| Objective:To measure the expression rate, expression location of ASPM (Abnormal Spindle-Like Microcephaly) and MGMT (O6-methylguanine-DNA methyltransferase) in glioma patients, and investigate the correlation of their expression level and tumor pathological grade, then combine with the survival data postoperatively, aim to provide basic theoretical foundations and treatment strategy for potential molecular targeting therapy in glioma.Method:Forty-one cases of gliomas patients (21 males and 20 females) via pathological diagnosis were collected from 2013 January to 2014 September. Age distribution ranges from 24 to 74 years, the average age is 49.10±10.89 years. According to WHO pathological grading, these cases were divided into grade Ⅱ, grade Ⅲ and grade Ⅳ. This study include 11 cases of grade Ⅱ glioma,15 cases of grade Ⅲ glioma, and 15 cases of grade Ⅵ glioma. All specimen were collected from fresh tumor tissue, a part of which were stored in clean cryogenic vials and reserved in liquid nitrogen, the other part were immobilized in formalin and were reserved as paraffin-embedded tissue sample. Meanwhile,10 cases of normal brain tissues by cortex fistulization from brain tumor resection were collected as control group. The expression levels of ASPM and MGMT of the cases were measured by PCR and IHC via Gene Tools, and the correlation between their expression level, tumor grade and life span of patients were analyzed by GraphPad Prism and SPSS 19 software.Results:1. The study included 41 patients with glioma, tissue specimens were positive for PCR detection ASPM mRNA expression in 21 cases, the total positive rate was 51.21%, in which grade Ⅱ was 27.27%(3/11), grade Ⅲ was 53.33%(8/15), grade Ⅳ was 66.67%(10/15), but no statistical significant difference was shown (P>0.05), the expression of normal brain tissue was not detected. Moreover, ASPM mRNA relative expression level between the grade Ⅱ, Ⅲ, Ⅳ tumors had no statistical significant difference by one-way ANOVA (analysis of variance) (P=0.22), Student t test showed significant difference between low grade glioma (LGG) group and high grade glioma (HGG) group (P=0.05<0.05).Kaplan-Meier survival curves were plotted, the average survival time of ASPM positive expression is less than the survival time of patients with negative expression by Log-rank and Breslow test, the difference was statistically significant (P<0.05). Low expression of ASPM mRNA in patients have longer median survival period than moderate and highly expressed ones, but no significant difference was demonstrated (P>0.05).The mRNA of MGMT were positive in all 41 glioma patient and normal brain, the positive rate was 100%. MGMT mRNA relative expression level between the different grade tumors and different malignant degree had no statistical difference (P>0.05).Using spearman correlation analysis, we found that the expression levels of ASPM mRNA have positive correlation with the tumor grade (P<0.05, r=0.315). MGMT mRNA expression levels exist heterogeneous in different pathological grade gliomas, but no correlation was shown (P=0.911). There was no correlation between expression of mRNA of ASPM and MGMT in glioma cells(P>0.05).2. Immunohistochemical analysis showed positive ASPM expresssion was different at different grade of glioma cells, but no significant difference (P> 0.05) was shown, and no correlation between tumor pathological grade was demonstrated (P>0.05).3. There was significant difference in patient age between LGG and HGG patients by Student t-test. (P=0.003), the median age in LGG patients was 41.09±3.03 years, and 52.03±1.79 years in HGG patients. Moreover, Spearman correlation analysis indicated that the degree of malignancy were positively correlated with the patient age (correlation coefficient r=0.445, P=0.004).Conclusions:1. ASPM expressed in glioma tissues was significantly higher than in normal brain tissue, the higher tumor grade, the higher the expression level, which suggested that ASPM may be involved in glioma cell proliferation. The survival time of patients with ASPM positive expression was significantly shorter than the negative expression. ASPM mRNA, is moderate and highly expressed in a shorter survival period in patients than in patients with low expression. It suggesting that increased expression of ASPM may indicate poor prognosis in patients with shorter survival.2.The mRNA expression levels of MGMT is heterogeneity in different pathology grade, there is no correlation between MGMT expression, glioma malignancy, cell division and proliferation.3. There is no correlation between ASPM and MGMT expression in glioma in mRNA and protein level, which imply that ASPM is not related to MGMT induced drug-resistance of chemotherapy and shorten survival time by drug-resistance.4. The age of onset is related to tumor grade, the higher the age is, the higher the grade is. |
PDF Full Text Request