Clinicopathological relevance of Ki-67 expression and its association with immunoprofile in breast cancer

Abstract

Background: Ki-67 is a widely used proliferation marker in breast carcinoma; however, its prognostic relevance remains inconsistent due to variability in assessment and lack of standardized cut-offs. Its correlation with established clinicopathological parameters and hormone receptor status continues to be an area of active investigation. Objectives were to evaluate Ki-67 expression and determine its association with clinicopathological features and immunohistochemical markers (ER, PR, HER2/neu) in invasive breast carcinoma. Methods: This hospital-based cross-sectional study included 88 cases of primary invasive breast carcinoma. Ki-67 expression was assessed by immunohistochemistry and categorized as low (<20%) or high (≥20%). Associations with tumor size, grade, lymph node status, lymphovascular invasion, perineural invasion, and hormone receptor status were analyzed using Chi-square/Fisher’s exact test. A p<0.05 was considered statistically significant. Results: High Ki-67 expression (≥20%) was observed in 44.3% of cases. Significant associations were noted between high Ki-67 expression and larger tumor size (p=0.018), higher histological grade (p=0.013), lymphovascular invasion (p=0.001), perineural invasion (p=0.002), and HER2/neu positivity (p=0.001). No significant association was found with age, lymph node metastasis, ER status, PR status, combined ER/PR status, or triple marker status. Conclusions: Ki-67 expression demonstrates significant association with adverse pathological features and HER2/neu positivity, supporting its role as an adjunct prognostic marker in invasive breast carcinoma. Incorporation of Ki-67 into routine evaluation may enhance risk stratification, particularly in resource-limited settings; however, standardization of assessment methods remains essential for its optimal clinical utility.