Immunohistochemical study of fibroblast activation protein and α-smooth muscle actin expression and distribution in triple-negative breast cancer

Document Type : Original Article

Authors

1 Pathology Department, Faculty of Medicine, Tanta University, Tanta, Egypt

2 Pathology Department, Faculty of Medicine, Tanta University, Egypt

Abstract

Background: Triple-negative breast cancer constitutes 10-20% of all breast cancers, and are more frequent in younger patients with a poor prognostic outcome. The tumor microenvironment is formed of activated fibroblasts (FAP) which are known as cancer-associated fibroblasts, which can be detected by fibroblast activation protein [FAP] and α-smooth muscle actin [α-SMA]. Aim: The aim of the work is the evaluation of the expression and distribution of FAP and α-SMA in triple-negative breast cancer. Material and Methods: This study was carried on 100 paraffin blocks from pathologically proved triple-negative invasive breast cancer patients and subjected to immunostaining of SMA and FAP antibodies, Evaluation of antibodies expression according to its distribution in tumor margin and in the tumor center. Results: There were significant differences between FAP as well as SMA expression in the tumor center and tumor margin, where FAP and SMA expression in the tumor center was positively correlated with tumor size and grade. In contrast to tumor margin, FAP and SMA expression were negatively correlated with the tumor size and lymph node metastasis. Conclusion: We speculated that high FAP expression and α-SMA expression in the tumor center, but not the tumor margin, is correlated with poor patients clinicopathological parameters.

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