Immunohistochemical Expression of CD68 in Triple Negative Invasive Ductal Carcinoma of the Breast and its Correlation with Clinicopathological Parameters

Introduction: Triple negative breast cancer (TNBC) is an aggressive form of breast cancer associated with a poor prognosis. No targeted treatment is available for this subtype. Tumor microenvironment (TME) has been increasingly considered a diagnostic and a prognostic biomarker and a therapeutic target for breast cancer. Tumor associated macrophages (TAM) are a pivotal member of TME and have been proposed as potential targets of therapy. Material and Methods: The immunohistochemical expression of CD68+ve TAM was studied in both tumor stroma (TS) and tumor nest (TN) in 50 cases of triple negative invasive ductal carcinoma as well as in 10 control cases of benign breast lesions. Results: The cases were divided into high or low density groups according to the median. The median in CD68+ve TAM in TS was (61.88), while in CD68+ve TAM in TN was (49.88). The expression of CD68+ve TAM in TS was low in 22 cases and high in 28 cases, while its expression in TN was low in 35 cases and high in 15 cases. There was no statistical association between high CD68+ve TAM in TN and different clinicopathological parameters, meanwhile a statistically significant association was found between high CD68 +ve TAM in TS and tumor grade, lymph/vascular invasion and lymph node metastasis. Conclusions: High expression of TAM in TS, but not in TN, is of clinical significance in patients with TNBC and highlights the importance of analyzing the localization rather than merely the presence of TAM as a marker for prognosis and a potential target for future treatment of triple negative breast cancer.