Study of mutated p53 protein by immunohistochemistry in urothelial neoplasm of urinary bladder.

It is difficult to predict which urothelial neoplasm would subsequently recur or progress to muscle invasive tumours or produce metastasis.The aim and objective of the study were to evaluate the scope of immunohistochemical expression of p53 in human urothelial neoplasms with regard to grade, stage and outcome of the patients. Eighteen consecutive patients were taken and urothelial tumour samples were obtained from transurethral resection or surgical excision. Histopathological examinations were performed and the grading was done according to the WHO/ISUP consensus classification of urothelial neoplasms. Immunohistochemical staining for p53 was performed on formalin fixed paraffin embedded tissue sections with appropriate positive and negative control. It was found 3 patients with papillary urothelial neoplasm of low malignant potential (PUNLMP), 5 cases of papillary low grade urothelial carcinoma, 10 patients with papillary high grade urothelial carcinoma including 2 cases of invasive urothelial carcinoma. All three PUNLMP cases showed negative results. Four out of 5 low grade papillary urothelial carcinoma had nuclear p53 accumulation, while all of the 10 papillary high grade carcinoma had high p53 index. The finding of negative p53 staining in PUNLMPs and high p53 index in high grade papillary urothelial carcinomas and invasive carcinomas support the notion that mutation of p53 gene might be unrelated to the development of urothelial neoplasms but definitely play a crucial role in progression of the malignancy.