Background and Objective: HER-2 (human epidermal growth factor receptor 2) is one such gene that can play a role in the development of breast cancer by making HER-2 proteins (receptorson breast cells). Normally, HER-2 receptors control breast cells grow and Division.  HER-2 protein over expression is the cause of up to 20% of breast cancers. The phosphoinositide 3 kinase (PI3K) pathway is important in the oncogenic function of HER-2. 

It has been reported compounds including Se, such as selenite significantly attenuated oxidative-stress-induced activation of the PI3K signaling pathways and can exhibit antitumor activity by downregulating PI3K activation.

 In this study, we evaluated Association of tissue selenium level and Human epidermal growth factor receptor 2 (HER-2) expression in breast cancer.

methods:

Se contents and expression of HER-2 were determined in 30 tissue collected from 30 women diagnosed with breast cancer based on immunohistochemistry (HER-2) and atomic absorption (Se).

Results:

About 30% of the samples were positive for HER-2 expression. Mean level of tissue selenium in tumors for positive and negative HER-2 was 268.15 µg/l and 206.43µg/l respectively. So, there was no significant association between selenium level and HER-2 expression. (p>0.005)

Conclusion:

There is no Association of tissue selenium level and HER-2 expression in breast cancer.

Keyword:

Selenium, HER-2, breast cancer

ABSTRACT
              Background and Objectives: Recently, the incidence of breast cancer has increased drastically worldwide. Therefore, the identification of novel diagnostic biomarkers is essential for improving treatment outcomes and prognosis. Estrogen receptor (ER) and progesterone receptor (PR) are routinely available in breast cancer specimens. Semi-quantitative assessment of ER and PR is important for prognosis. Even with the development of genomic tests, hormone receptor status remains the most significant predictive and prognostic biomarker. Selenium is known to protect mammary epithelial cells against oxidative DNA damage and early carcinogenetic events. Since overexpression of ER and PR is common in breast cancers, we aimed to evaluate association of tissue selenium level and ER and PR expression in breast cancer.
              Methods: Sixty tissue samples (30 tumors and 30 tumor margins) were collected from patients with breast cancer. Selenium level was measured using graphite furnace atomic absorption spectroscopy and ER/PR expression was evaluated using immunohistochemistry.
              Results: About 60% of the samples were positive for ER/PR expression. Mean level of tissue selenium was 209.54 µg/L in tumors and 185.04 µg/L in tumor margins that were ER/PR positive. In addition, mean selenium level was 243.39 µg/L and 168.06 µg/L in ER/PR-negative tumors and tumor margins, respectively. There was no significant association between selenium level and ER/PR expression (P>0.05).
              Conclusion: There is no association between tissue Se level and ER/PR expression in breast cancer.
              Keywords: Selenium, Estrogen receptor (ER), progesterone receptor (PR), breast cancer.

ABSTRACT
             Background and Objectives: In this study, nanosilica modified with HS-SiO₂ thiol groups was utilized as adsorbent for solid phase extraction, as a fast and reliable method of preconcentration and separation of very small quantities of selenium ions from water and blood samples.
             Methods: The samples included four natural water samples and one biological sample (blood serum) prepared in volumes of 25, 100, 200, 300, 400 and 500 ml. The samples were analyzed by solid phase microextraction, using thiolated-nanosilica (as adsorbent), ultraviolet-visible spectrophotometry and atomic absorption spectroscopy.
             Results: Optimized conditions for preconcentration of a 25 ml 0.2 mg/l selenium solution were pH 5, 40 mg of adsorbent, sample-adsorbent mixing time of 15 minutes and 5 ml of 2N sulfuric acid as detergent. The volume limit and concentration factor were 400 and 80, respectively. Limit of detection and relative standard deviation of the method were 0.46 μg/l and 0.9%, respectively.
             Conclusion: This study is the first to successfully utilize thiolated nanosilica for measuring low selenium levels. Thiolation of the absorbent increases selenium adsorption by thiolated-silica compared to SiO₂.
             Keywords: Solid phase extraction, Selenium, Preconcentration, Nano, UV-visible spectrophotometry.

ABSTRACT
           Esophageal cancer (EC) is one of the most common types of cancer, especially in Asia. Esophageal squamous cell cancer (ESCC) is the most important histological subtype of EC, which accounts for 90% of all EC cases worldwide. ESCC is highly prevalent in Turkey, Iran, Kazakhstan and northern and central parts of China. Selenium is an essential micronutrient that is required for cellular functioning and synthesis of several selenoproteins. It also modulates the antioxidant defense system, cell cycle and apoptosis. This article reviews the most important molecular mechanisms of EC and investigates the association between selenium level and incidence of EC in high-risk areas.
           Keywords: Esophageal cancer, selenium, selenoprotein.