Investigating Intensity and Percentage of p53 Nuclear Expression in Prostate Cancer: Findings from a Cohort of U.S. Military Veterans.

Abstract

Background: Next-generation sequencing has revealed TP53 alterations in localized prostate cancer (PCa), suggesting growing clinical potential for p53 immunohistochemistry (IHC). Prior research supports the use of IHC for the detection of p53 overexpression to predict the presence of TP53 alterations known to be associated with adverse outcomes. However, to reach a consensus definition of p53 overexpression in PCa, further insights are needed. This study aimed to compare two fundamental approaches of evaluating p53 expression across a variety of specimens regarding PCa progression.

Methods: This study included 84 patients (75% self-identified as African American) diagnosed with PCa between 1996 and 2021 at the DC VA Medical Center. Representative sections of core biopsies, radical prostatectomies, transurethral prostate resections, and metastatic deposits were examined. p53 nuclear expression was scored according to the highest intensity observed (0, 1+, 2+, 3+) and the percentage (0%, <1%, 1-5%, >5%) of tumor cells expressing any level of intensity in the aggregate tumor area. All slides were reviewed by two independent pathologists. Pertinent clinical data were collected.

Results: A total of 34 patients (40%) exhibited p53 nuclear expression, of which 18 (21%) showed the maximum (3+) intensity. The presence of maximum intensity, regardless of percentage, was found to be associated with Grade Group (p < 0.001), higher PSA at biopsy (p < 0.001), BCR (p < 0.001) and metastasis (p < 0.001). Importantly, maximum p53 intensity was identified only in patients who developed metastatic disease.

Conclusions: Maximum (3+) p53 nuclear intensity of any percentage is highly associated with disease progression in PCa, suggesting that optimal determination of p53 overexpression should incorporate intensity.