# Immunohistochemical Evaluation of p53 and Its Association With Prognostic Parameters in Breast Cancer

## TL;DR

This study finds that p53 positivity in breast cancer is linked to more aggressive tumor features and certain molecular subtypes.

## Contribution

The study provides new insights into p53's association with specific clinicopathological and molecular features in breast cancer.

## Key findings

- P53 positivity was found in 57.5% of breast cancer cases.
- P53 positivity was significantly associated with larger tumor size and higher Ki-67 index.
- P53 was most common in aggressive subtypes like HER2-enriched and luminal B tumors.

## Abstract

Background

P53 is a tumour suppressor gene that is commonly altered in breast cancer, potentially affecting tumour behaviour and prognosis. However, the clinicopathological and molecular associations vary across studies. Hence, the present study aims to evaluate p53 positivity and its association with clinicopathological parameters and molecular subtypes in invasive breast carcinoma.

Aims and objectives

To evaluate p53 positivity in invasive breast carcinoma and analyse its association with key clinicopathological parameters.

Methods

A cross-sectional observational study was undertaken in the pathology department of a tertiary care hospital. Immunohistochemistry was used to measure p53 expression, which was then linked with clinicopathological features like tumour size, histological grade, lymph node status, lymphovascular invasion, hormone receptor status, human epidermal growth factor receptor 2 (HER2) status, Ki-67 proliferation index, and molecular subtype. Statistical analysis was done using SPSS software. Chi-square and Fisher's exact tests were used for correlation analysis, and p-values <0.05 were considered significant.

Results

P53 positivity was detected in 57.5% of the cases. P53 positivity was shown to be significantly associated with greater tumour size (p=0.029) and a high Ki-67 index (p=0.042) whereas histological grade, lymph nodal metastasis, lymphovascular invasion or hormone receptor status did not show statistical significance. Although hormone receptor-negative tumours showed more frequent p53 positivity status compared to a negative status, the results were not significant (p=0.052). P53 positivity was most frequent in aggressive molecular subtypes of tumours, like HER2-enriched (77.8%) and luminal B (75%) tumours.

Conclusion

P53 expression is associated with aggressive clinicopathological features like large tumour size, high Ki-67 index and the HER2-enriched subtype, suggesting its role in tumour progression and aggressiveness. Further, large multicentric studies with survival analysis are needed to confirm its clinical validity.