# Evaluation of p53 Immunohistochemical Expression Using Open-Source Software for Digital Image Analysis. A Tissue Microarray Study of Penile Squamous Cell Carcinomas

## TL;DR

This study shows that open-source software can accurately analyze p53 protein levels in penile cancer tissue samples, offering a cost-effective alternative to traditional methods.

## Contribution

The study demonstrates the feasibility of using open-source digital image analysis for p53 evaluation in penile SCC.

## Key findings

- Digital analysis showed high correlation with visual estimation of p53 expression.
- Open-source tools can reduce interobserver variability in immunohistochemical evaluations.
- The approach is applicable to other tumor types beyond penile SCC.

## Abstract

The addition of molecular biomarkers is needed to increase the accuracy of pathologic factors as prognosticators of outcome in penile squamous cell carcinomas (SCC). Evaluation of these biomarkers is usually carried out by immunohistochemistry. Herein we assess p53 immunohistochemical expression on tissue samples of penile SCC using freely-available, open-source software packages for digital image analysis. We also compared the results of digital analysis with standard visual estimation. Percentages of p53 positive cells were higher by visual estimation than by digital analysis. However, correlation was high between both methods. Our study shows that evaluation of p53 immunohistochemical expression is feasible using open-source software packages for digital image analysis. Although our analysis was limited to penile SCC, the rationale should also hold for other tumor types in which evaluation of p53 immunohistochemical expression is required. This approach would reduce interobserver variability, and would provide a standardized method for reporting the results of immunohistochemical stains. As these diagnostic tools are freely-available online, researchers and practicing pathologists could incorporate them in their daily practice without increasing diagnostic costs.