Ki-67 is a Prognostic Factor only With High Histological Grade and Low Progesterone-Receptor in early Estrogen-positive HER2-Negative Breast Cancer

Abstract

Background: To evaluate the prognostic significance of Ki-67, histological grade, and progesterone receptors in patients with estrogen receptor-positive and human epidermal growth factor receptor 2-negative (HER2-) early breast cancer. Researchers have extensively examined tumor proliferative activity using the Ki-67 antigen over the past decade and have shown its value as a prognostic marker in breast cancer; however, its clinical utility remains debated.

Methods: A retrospective study covering the period from 2016 to 2022 included 106 patients from the Brcko District with early estrogen-positive, HER2 receptor-negative breast cancer. The average age of the patients was 62.37±11.65 years. We divided the patients into groups based on high or low Ki-67 expression, high or low histological grade, and combined high or low Ki-67 expression with high or low progesterone receptor levels. We conducted multiple logistic regression analysis to evaluate factors related to disease relapse and mortality.

Results: Multiple logistic regression analysis identified that the most significant prognostic factors for recurrence of early breast cancer with positive estrogen and negative HER2 receptors are high histological grade, especially when combined with high Ki-67 expression. The analysis also indicated that the key prognostic factors for mortality in these patients are high histological grade, elevated Ki-67 levels, and the combination of high histological grade with high Ki-67 expression. Low PR expression was associated with higher grade and elevated Ki-67.

Conclusion: Ki-67 appears to have prognostic significance primarily when combined with high histological grade and low progesterone receptor expression, suggesting that this biomarker panel may help refine risk stratification in ER-positive, HER2-negative early breast cancer.