p53 and p21/WAF-1 overexpressions in prostatic adenocarcinoma.

OBJECTIVES This study was carried out to determine the role of p53 and p21 in the pathogenesis of prostatic adenocarcinoma and their association with tumour grade. METHOD Sixty-seven histologically confirmed prostatic adenocarcinoma cases collected from Hospital Universiti Kebangsaan Malaysia and General Hospital Kuala Lumpur were studied. The formalin-fixed paraffin-embedded tissues were stained with monoclonal antibody p53 (clone DO-7) and p21 (clone SX II8) using standard avidin-biotin complex immunohistochemistry (IHC) after microwave antigen retrieval. The adenocarcinomas were graded histologically according to Gleason score: low grade = score 2-4, intermediate grade = score 5-7, high grade = score 8-10. Histological grade was analysed against IHC expressions of p53 and p21 and against patient age and ethnicity. RESULTS IHC positivity for p53 was expressed in 1/2 (50%) low grade, 14/33 (42%) intermediate grade, and 21/32 (66%) high grade tumours. p21 was expressed in 0/2 low grade, 16/33 (48%) intermediate grade and 15/32 (47%) high grade tumours. p53 and p21 expressions did not show statistically significant correlation with the different grades of prostatic adenocarcinoma or with each other (p = 0.42). There was no correlation between tumour grade and age or ethnicity. CONCLUSION Although the p53 positivity rate was higher in high-grade prostate adenocarcinoma, this was not statistically significant. We found that a combined expression of p21 and p53 was not correlated with tumour grade. We could not confirm that p21 expression was dependent on p53 expression.