Expression of Ki-67 and p53 in Triple-negative Breast Cancer: A Clinicopathological Study

Abstract

Background: Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype, categorized by a lack of expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2, associated with poor prognosis. Therefore, need to take reliable biomarkers are essential for prognostic stratification and guiding treatment decisions. This study evaluates the clinicopathological significance of Ki-67 and p53 expression in TNBC within an Indian cohort. Methods: A prospective observational study was conducted on 23 histologically confirmed TNBC cases diagnosed between January 2023 and June 2024. Consecutive sampling was used to include all eligible, treatment-naïve patients. Clinicopathological parameters were recorded, and immunohistochemistry (IHC) for Ki-67 and p53 was performed on formalin-fixed paraffin-embedded tissue. Associations between biomarker expression and tumor grade, size, and lymph node status were analyzed using Chi-square/Fisher’s exact test and binary logistic regression. Results: The mean patient age was 48.6 years (range: 32–68). Most tumors (69.6%) were >2 cm, 73.9% were Grade III, and 56.5% had lymph node metastasis. High Ki-67 expression (>20%) was observed in 78.3% of cases, showing a significant association with Grade III tumors (P = 0.01) and lymph node metastasis (P = 0.03). p53 positivity (>10%) occurred in 65.2% of cases, correlating significantly with tumor grade (P = 0.04) but not with nodal status. Binary logistic regression confirmed Ki-67 as an independent predictor of Grade III histology (odds ratio [OR] = 6.75, P = 0.04) and nodal metastasis (OR = 5.40, P = 0.047), whereas p53 did not retain independent prognostic significance. Conclusion: High Ki-67 expression is a robust and independent prognostic marker in TNBC, associated with high-grade histology and lymphatic spread, supporting its integration into routine pathological evaluation. p53 expression shows limited prognostic utility when used alone but may have value in multi-marker panels. Larger studies with long-term survival data are warranted to validate these findings and refine biomarker-guided management strategies in TNBC. © 2025 Biomedical and Biotechnology Research Journal (BBRJ)