Expression of bel-2 Oncoprotein in Bladder Tumor

Choi, Phil Seon; Lee, Gilho; Lee, Min Chul

Abstract

PURPOSE: Expression of bel-2 is associated with inhibition of apoptosis and extension of cell survival. We investigated the expression of bel-2 oncoprotein in human bladder tumor.
MATERIALS AND METHODS
The expression of bel-2 oncoprotein was investigated immunohistochemically in formalin-fixed and paraffin-embedded tissue specimens from 43 patients with primary transitional cell carcinoma in urinary bladder. Thirty four were superficial bladder tumors and nine were invasive bladder tumors. In histology grade according WHO grading there were 9 grade 1,21 grade II and 13 grade III.
RESULTS
Strong positive staining was 5(11.62%), positive staining 13(30%) and negative staining 25(58%). Random distribution through the cancerous epithelium presented in 3 tumors but the other 15 tumors demonstrated cystoplasmic staining restricted to basal epithelial cells. Positive immunoreaction for bel-2 was found in 3 out of 9 invasive bladder tumors, while 15 of 34 superficial tumors showed positive staining. There was no significant correlation between bel-2 expression and tumor stage(p=0.56). 6 of grade I, 9 of grade II and 3 of grade III bladder tumors showed positive staining. There was no significant correlation between bcl-2 expression and tumor grade(p=0.12).
CONCLUSIONS
The findings suggest that no clear relationship was found between tumor grade, stage and bel-2 expression.