The Prognostic Role of Ki-67 in Invasive Breast Cancer: Correlation with ER, PR, and HER2 Receptor Status

Abstract

Invasive breast cancer is a major health challenge worldwide, requiring precise biomarkers to guide prognosis and personalized treatment strategies. This study investigates the role of Ki-67, a cell proliferation marker, in breast cancer prognosis by examining its correlation with traditional biomarkers—estrogen receptor (ER), progesterone receptor (PR), and HER2—as well as its association with tumor characteristics such as size, lymph node involvement, and TNM staging. A cohort of 50 patients with invasive breast cancer was analyzed for Ki-67 expression levels and receptor status. Statistical findings show that high Ki-67 expression is significantly associated with ER-negative, PR-negative, and HER2-positive tumors, highlighting a trend toward aggressive disease phenotypes. Higher Ki-67 levels were also observed in larger tumors, cases with increased lymph node involvement, and advanced TNM stages. Kaplan-Meier survival analysis revealed that high Ki-67 expression is associated with reduced overall and disease-free survival, particularly in ER-negative and triple-negative breast cancers. These findings support the prognostic utility of Ki-67 in assessing tumor aggressiveness and guiding treatment intensity. By integrating Ki-67 with established markers, clinicians can make more informed decisions, enhancing personalized treatment approaches for breast cancer patients.