Bcl-2 expression is a cell lineage dependent and p53 independent event in urinary bladder carcinoma

ABSTRACT

To evaluate the expression of bcl-2 and p53 onco-proteins in normal, hyperplastic, metaplastic, dysplastic and malignant urothelium and their relationship to cell lineage and histopathological parameters. Forty one formalin-fixed and paraffin-embedded blocks were included, thirty six were urinary bladder carcinomas and five cystoscopic normal urinary bladder mucosa. Cases of urinary bladder carcinomas were assessed for grade, stage, nodal metastasis, and presence of hyperplasia, metaplasia, and dysplasia in adjacent mucosa. There were 26 squamous cell carcinoma [SCC], 10 transitional cell carcinoma [TCC], 5 epithelial hyperplasia, 13 squamous metaplasia, 3 glandular metaplasia and 6 focal dysplastic changes. Sections were stained immunohistochemically for the expression of bcl-2 and p53. bcl-2 protein was expressed in basal cells of the normal and hyperplastic urothelium, whereas p53 was not detected. Also bcl-2 was detected in all three cases of glandular metaplasia but p53 was negative. Immunoreactivity for bcl-2 was present in eight of 36 cases [22.2%] [four SCC and four TCC]. Nuclear staining for p53 was observed in sixteen of 36 cases [44.4%] of urinary bladder carcinoma, including 11 of 26 [42.3%] SCC and 5 of 10 [50%] TCC. The expression of bcl-2 and p53 oncoprotein is not correlated with histopathological parameters regarding tumor grade, stage and nodal metastasis in urinary bladder carcinoma. Our results also do not indicate inverse relationship of p53 and bcl-2 immunoreactivity. We suggested that bcl-2 expression was cell lineage dependent as evident by [100%] positively in glandular metaplasia and two foci of adenocarcinoma and significantly high prevalence in TCC [40%] than SCC [15.4%]