Lack of Association between Selenium Level and Human Epidermal Growth Factor Receptor 2 (HER2) Expression in Breast Cancer Tissue

Background and Objectives: Human epidermal growth factor receptor 2 (HER2) is a gene involved in development of breast cancer. Normally, HER2 receptors control breast cells growth and division. HER2 overexpression is the cause of almost 20% of all breast cancer incidents. The phosphoinositide 3 kinase (PI3K) pathway is important in the oncogenic function of HER2. It has been reported that compounds, such as selenium significantly attenuate oxidative stress-induced activation of the PI3K pathway, and can exert antitumor effects by downregulating PI3K activation. In this study, we evaluated association of selenium level and HER2 expression in breast cancer tissue. Methods: Atomic absorption spectrometry and immunohistochemistry were used to evaluate selenium content and HER2 expression in 30 tissue sets (tumor and adjacent tissue) collected from 30 women diagnosed with breast cancer. Results: HER2 was expressed in about 30% of the samples. In HER2-positive tissues, mean level of selenium was 268.15 μg/L in tumors and 165.36 μg/L in tumor margins. In HER2-negative tissues, mean level of selenium was 206.43 μg/L in tumors and 184.39 μg/L in tumor margins. There was no significant association between selenium level and HER2 expression (P>0.05). Conclusion: Based on the results, we conclude that there is no association between Se level and HER2 expression in breast cancer tissue.