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.