Diagnostic Value of Ki-67 Expression and its Correlation With Clinical Symptoms and Pathological Indicators in Breast Cancer Patients

Background: Breast cancer (BC) constitutes approximately one-third of all malignancies diagnosed in women. The identification of suitable biomarkers is crucial for forecasting patient prognosis. This study sought to assess the utility of Ki-67 as a prognostic marker in patients with BC and to examine the relationships between Ki-67 expression and various clinicopathological parameters. Methods: This retrospective cross-sectional study reviewed all medical data of BC patients treated at Urmia Imam Khomeini hospital between July 2022 and March 2023. Clinical files were analyzed to extract demographic information (including age), clinical details (e.g., patient-reported symptoms), and examination findings (e.g., skin discoloration). Additionally, pathological characteristics were documented, encompassing tumor type, grade and stage, size, and the levels of expression of human epidermal growth factor 2 (HER2), progesterone receptor (PR), and estrogen receptor (ER). Furthermore, the Ki-67 index expression was recorded. Results: A total of 282 patients participated in the study, with a mean age of 28.58±10.10 years. A significant inverse correlation was observed between age and Ki-67 expression (r=-0.616, P<0.001). Moreover, there was a positive correlation between tumor size and Ki-67 expression (r=0.423, P<0.001). Increased levels of Ki-67 were significantly associated with advanced tumor stages (P<0.001) as well as higher tumor grades (P<0.001). Ki-67 expression exceeding 20% exhibited a sensitivity of 100% and a specificity of 35.50% in differentiating between early-stage (stages 1 and 2) and advanced-stage (stages 3 and 4) BC. Conclusion: The Ki-67 index serves as a crucial biomarker for evaluating the severity and progression of BC. These findings highlight the potential of Ki-67, in conjunction with other biomarkers, to enhance prognostic accuracy and inform personalized therapeutic strategies for patients with BC.