Abstract
Background: Breast cancer is the most common malignancy among women globally, with distant metastasis being the primary cause of mortality. The tumor microenvironment, particularly Tumor-Associated Macrophages (TAMs), plays a crucial role in cancer progression. This study aimed to evaluate the association between CD163 expression in TAMs and the presence of distant metastasis in patients with breast cancer. Methods: A cross-sectional study was conducted on 71 patients with invasive breast cancer at Hasanuddin University Hospital in Makassar. CD163 expression in TAMs was analyzed using immunohistochemistry in formalin-fixed paraffin-embedded tissues. Clinical and pathological data were collected from the medical records. Statistical analyses were performed using the Chi-square test for categorical data and the Mann-Whitney U test for continuous data, with significance defined as p < 0.05. Associations are presented as odds ratios (ORs). Results: Of the 71 patients, 59.2% showed a high level of CD163 expression in TAMs. A significant association was observed between high CD163 expression and advanced cancer stage (p < 0.001), high histopathological grading (p < 0.001), and distant metastasis status (p < 0.001). After adjusting for key confounders, high CD163 expression was associated with an 11.2-fold increase in the odds of distant metastasis (adjusted OR = 11.2; 95% CI: 3.5–35.8; p < 0.001). Conclusion: High CD163 expression in TAMs is significantly associated with an increased risk of distant metastasis in breast cancer and correlates with more aggressive tumor characteristics. These findings indicate that CD163-positive TAMs represent a potential prognostic biomarker for risk stratification in patients with breast cancer.