P53 and PCNA overexpression in papillary urothelial tumors : an immunohistochemical study

Abstract EN

Objective : The aim of the present study was to evaluate the expression of P53 protein and PCNA and their correlation with different papillary grades of urothelial tumors according to WHO / ISUP classification.

Methods : Thirty five cases of urothelial tumors and their corresponding paraffin blocks from 2009-2010 were submitted in this study in the Department of Pathology, College of Medicine, Kufa University.

Ten biopsies of benign urothelium (cystitis) were considered as control group.

ABC method was used to determine the expression of p53 and PCNA in these cases, Two hundred cells were counted and the percentage of cells positive for p53 and PCNA (labeling index [LI]) was counted.

Immunohistochemical positivity was defined as strong, homogenous nuclear staining.

Statistically Chi square, Fisher exact probability and correlation co-efficient tests were used by the help of SPSS version 10.

Results : P53 expression was detected in 20 cases of TCC with mean LI of 27.4 %, while PCNA were detected in 24 samples out of 35 with mean LI of 48.2 % with significant levels of expression between malignant and benign urothelium (P < 0.05).

Regarding p53 expression, none of the benign lesions show positive results, while it was observed in 1 of 5 for papilloma with mean labeling index LI of 2 % and 5 of 12 for LMP with LI 14.3 %.

In contrast, p53 was a feature of papillary carcinoma it expressed in 8 of 11low- grade and 6 of 7 high grade papillary urothelial carcinoma with mean LIs of 36.8 % and 53.4 % respectively.

PCNA positivity was as follow : benign urothelium (mean LI 3.5 %), papilloma (mean LI 25 %), LMP tumors (mean LI31.6 %), low grade papillary carcinoma (mean LI 63.3 %), and high grade papillary carcinoma (mean LI 69 %).

PCNA expression separate benign urothelium and papilloma from tumors of LMP, low and high grade papillary carcinoma.

Conclusion : An increased in proliferative index as demonstrated by immunohistochemical staining for PCNA is most often seen in papillary carcinoma and tumors of LMP.

While p53 positivity is mainly a feature of low grade and high grade papillary carcinoma.