[Proliferative activity and p53 expression in transitional cell carcinoma of the urinary bladder].
Mutations of the p53 gene are important mechanisms in malignant transformation and are associated with dysregulation of normal cell growth. In the present study the expression of mutated p53-protein and proliferating cell nuclear antigen (PCNA) was investigated in a series of 31 human transitional cell carcinomas (TCC) by immunohistochemistry (IHC). The number of PCNA-positive cells and the pattern of expression was distinct in normal urothelium being confined to the basal cell layer. In dysplastic urothelium and in Carcinoma in situ (CIS) PCNA-immunoreactive nuclei were irregularly distributed throughout all layers. In tumor cell complexes the pattern of PCNA-immunoreactivity was different in papillary and primary infiltrating TCCs. Densitometric quantification of the intensity of the PCNA-reactivity using image analysis revealed an increase from normal to dysplastic urothelium and from dysplastic urothelium to invasive tumors. 21/31 (68%) of the tumors and tumor-associated CIS showed overexpression of p53 varying in percentage, pattern and reaction intensity. The percentage of PCNA-positive cells was higher in tumors overexpressing p53. Double IHC showed colocalization of both molecules in a significant proportion of tumor cells suggesting a link of p53 overexpression and the abnormal proliferative activity. The present results show that p53 over-expression is found in a significant percentage of TCCs and indicate a close association with a defective growth regulation resulting in increased PCNA-levels and enhanced cellular proliferation.
Offner
F A
FA
Institut für Pathologische Anatomie, Universität Innsbruck.
Schäfer
G
G
Hittmair
A
A
Ofner
D
D
Grünewald
K
K
Weyrer
K
K
Mattern
D
D
Eberle
J
J
Mikuz
G
G
Feichtinger
H
H
D000704:Analysis of Variance; D000951:Antigens, Neoplasm / Q000032:analysis; D002278:Carcinoma in Situ / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002295:Carcinoma, Transitional Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002455:Cell Division; D015870:Gene Expression; D016158:Genes, p53; D006801:Humans; D007150:Immunohistochemistry; D009154:Mutation; D009687:Nuclear Proteins / Q000032:analysis; D018809:Proliferating Cell Nuclear Antigen; D016159:Tumor Suppressor Protein p53 / Q000032:analysis* / Q000096:biosynthesis; D001749:Urinary Bladder Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*
D000951:Antigens, Neoplasm; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D016159:Tumor Suppressor Protein p53