Relationship between P53, Bcl-2, Apoptosis and Histologic Grade of Brain Tumors

Abstract

We studied thirty benign and twenty-one malignant brain tumors in order to investigate the relationship between p53, bcl-2, apoptosis and histologic grade of brain tumors. For the study of p53 and bcl-2 gene expression, we used immunohistochemical staining method using monoclonal antibodies to p53 and bcl-2；and, for apoptosis, In-situ end labeling technique was used. The malignant group showed significantly higher p53 and apoptosis positive index(PI) than the benign group(mean p53 PI, malignant：16.0 benign：0.9/mean apoptosis PI, malignant：2.3 benign：0.2)(p＝0.003)；but bcl-2 positive index was not significantly different between two groups(p＝0.118). Correlation between p53 mutation and apoptosis PI was statistically significant(p＝0.012, Pearson coefficient＝0.349)；but correlation between bcl-2 expression and apoptosis PI was not(p＝0.318). Moreover, correlation between p53 mutation and bcl-2 expression was not statistically significant(p＝0.583). These results suggest that higher p53 mutation tends to exist in the group of tumors with higher malignant histologic grades. Furthermore, it can be concluded that greater DNA damage reflected by higher frequency of apoptosis tends to exist in the group of higher malignant histologic grade.