Breast cancer is a systemic disease that usually metastasizes before the diagnosis of the primary tumor. To develop novel treatment strategies, it is essential to identify the factors underlying tumorigenesis, invasion, and metastasis. This study aimed to assess the expression of Bmi-1, S100A4, and claudin-1 in immunostained specimens of breast cancer and correlate their immunohistochemical expression with the clinicopathological parameters to identify their impact on tumor behavior and carcinogenesis.Materials and methods
Bmi-1, S100A4, and claudin-1 immunohistochemical expressions were evaluated and analyzed in 50 paraffin-embedded specimens of breast cancer.Results
Bmi-1, S100A4, and claudin-1 expression was found in 58, 44, and 34%, respectively, of the studied cases. There was a significant positive association between Bmi-1 expression and tumor grade (P<0.001), lymphovascular invasion (LVI) (P<0.001), nodal involvement (pN) (P<0.001), distant metastasis (P=0.017), and tumor stage (P<0.001). There was a significant positive association between S100A4 expression and tumor size (P<0.001), tumor grade (P=0.007), LVI (P<0.001), nodal involvement (P=0.002), and tumor stage (P<0.001). There was a significant inverse association between claudin-1 expression with tumor size (P=0.04), grade (P<0.001), LVI (P<0.001), nodal involvement (P<0.001), and tumor stage (P<0.001). There was a positive association between Bmi-1 and S100A4, whereas claudin-1 was inversely associated with both markers.Conclusion
The loss of tight junctions represented by decreased claudin-1 expression and the acquisition of mesenchymal properties represented by Bmi-1 and S100A4 overexpression are considered adverse prognostic markers of breast cancer that denote an aggressive course. In addition, they are important for breast cancer progression, invasion, and metastasis.