The Study of Clinical Correlation between p53 Protein Overexpression and Ploidy in Transitional Cell Carcinoma of the Bladder

Lee, Gil Ro; Kim, Hyung Jee; Cho, Jae Heung; Chae, Yang Suk

Abstract

The p53 gene product has been detected in various human tumors. To investigate the overexpression of the p53 protein in bladder tumor as a marker of tumor progression, the correlation between the overexpression of the p53 protein in bladder and the pathologic grade, stage and survival rate was studied. Among specimens of 47 patients, 19 were from patients of superficial bladder tumor, 28 were from invasive bladder tumor according to pathologic stage, while 15 were from low grade and 32 were from high grade tumors according to Ash grade p53 overexpression was determined by immunohistochemistry using DO-7 primary antibody on paraffin embedded sections and flow cytometry was performed on cell suspensions derived from the same blocks. Histologically normal bladder tissue was used as a control group Conclusions were made as follows: 1. p53 protein overexpression was observed in 31 of 47 cases(65.9%). 2. Seven of 15 specimens from well differentiated tumor(Ash grade I, II) showed positive p53 staining while 24 of 32 cases from poorly differentiated tumor (Ash grade III,IV) showed positive staining. There is a significant correlation between p53 expression and poor pathological grade(p=0.05). 3. Nine of 19 cases with superficial bladder tumor showed positive staining while 22 of28 cases of invasive tumor showed positive staining. There is a significant correlation between p53 protein overexpression and invasive tumor(p=0.027). 4. Flow cytometric examination revealed that 24 of 30 cases with aneuploid group showed positive staining while 7 of 17 cases with diploid group showed positive staining. Aneuploid group showed high correlation with p53 protein overexpression(p=0.007). 5. The survival rates of patients, exhibiting p53 protein overexpression, were slightly worse than those with p53 negative tumor(p=0.08, Wilcoxon test) but this difference was not significant enough to count. 6. p53 protein overexpression was well correlated with grade, stage and flow cytometric analysis in bladder tumor. 7. Multiple linear regression study to survival rate showed the overexpression of p53 protein had little prognostic significance in bladder tumor compared with tumor grade and stage.