Prognostic Value of p53 Expression Intensity in Urothelial Cancers

To determine association of immunohistochemical expression intensity of p53 with grade and stage of urothelial cancers.

Descriptive cross-sectional analytical study.

Pathology Department, King Edward Medical University, Lahore, from January to December 2016.

Data of transurethral resection/radical cystesctomy urinary bladder biopsies was collected. Clinical, radiological and cystoscopic findings of patients were noted from patients' charts in the Urology Ward. Biopsies were graded histologically according to WHO 2004 grading system. TNM system was used for pathological staging. On selected slides, immunoshistochemistry for p53 was applied. Nuclear immunoreactivity was considered positive if present in >10% of tumor cells and negative if <10% of tumor cells. Intensity was considered weak (less than 15% cells) and strong (more than 15% cells). Data was analyzed by SPSS version 21. Linear-by-linear association was calculated between p53 expression and stage of urothelial tumors, Chi-Square test was used to see association between grade and intensity of p53. Qualitative variables, like grade and stage of carcinoma along with p53 expression, were calculated in terms of frequencies and percentages. P ≤ 0.05 was taken as significant.

Out of the 70 patients, 61 (87%) were males and 9 (13%) females. Out of 25 low grade lesions, 4 (16%) cases were p53 positive; and out of 45 high grade lesions, 41 (91%) cases were p53 positive. There was 33% (2/6 cases) positivity in Tis, 55% (16/29 cases) in T1, 72% in T2 (21/29), and 100% in T3a (5/5 cases) and T3b (1/1 case). Strong intensity of p53 staining was noted to be 5.4% (n=25) of low grade and 94.6% (n=45) of high grade tumors.

p53 expression was greater and more frequently strong in higher grade and stage of urothelial carcinoma. It can be used as a prognostic marker in predicting higher grade and stage of bladder cancer.