Expression of SATB1 and HER2 in breast cancer and the correlations with clinicopathologic characteristics.

Background: Special AT-rich sequence binding protein 1 (SATB1) is found acting as a "genome organizer" that functions as a landing platform to regulate tissue-specific gene ex-pression. In breast cancer cell lines it has been proven that SATB1 could upregulate the expression of the HER2. In this paper, the relevance of SATB1 and HER2 expression was assessed in human breast cancer tissues, and their influence on tumor histological grade and patients' survival was explored.

Methods: Using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), 169 patients with breast cancer were assessed for SATB1 expression, HER2 amplification and hormone-receptor (HR) expression. The effects of SATB1 expression on HER2 and HR expression as well as their association with clinicopathologic characteristics were further analyzed by statistical evaluation.

Results: SATB1 expression was correlated with HER2 expression in breast cancer(r = 0.191; p = 0.013). SATB1, HER2 and SATB1/HER2 co-expression was negatively correlated with HR expression (r = -0.228, p = 0.003; r = -0.338, p = 0.000; r = -0.527, p = 0.000, respectively). SATB1 and HER2 single positive and their co-expression were all significantly correlated with higher histological grade (r = 0.239, p = 0.002; r = 0.160, p = 0.038; r = 0.306, p = 0.003, respectively). Multivariate cox regression analyses showed that SATB1 and HER2 were independent risk factors for breast cancer patients, while HR was a protective factor for patients' survival. Comparing to SATB1 or HER2 single positive expression, SATB1/HER2 co-expression tended to have even worse prognosis.

Conclusions: SATB1 and HER2 performed a synergistic effect in breast cancer. Their expression correlated with poorly differentiated breast cancer and indicated an unfavorable prognosis.

Virtual Slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1400555050159723 .