Elevated Expression of Girdin in the Nucleus Indicates Worse Prognosis for Patients with Estrogen Receptor-Positive Breast Cancer

Background. Girdin was identified as a novel Akt substrate that contributes to a positive feedback loop between Girdin and Akt. Although several recent studies have demonstrated that Girdin is involved in tumor metastasis, the clinical implications of Girdin in breast cancer remain unclear. Methods. To retrospectively evaluate the prognostic value of Girdin in breast cancer, we performed an immunohistochemistry screening for Girdin using tissue microarrays constructed from 250 patients who were histologically confirmed as having invasive ductal breast carcinoma at the Fudan University Shanghai Cancer Center. Results. Our results demonstrated that the levels of Girdin in different subcellular distributions, including Girdin in the nucleus (GN) and the cytoplasm (GC) were each associated with the clinical parameters of breast cancer, including phospho-Akt (S473) [p = 0.014 for GN], phospho-Akt (T308) [p = 0.045 for GC], estrogen receptor (ER) [p = 0.012 for GN and p = 0.004 for GC], progesterone receptor (p = 0.028 for GC) and human epidermal growth factor receptor 2 status (p = 0.004 for GC). Moreover, we showed that elevated expression of GN indicated a worse disease-free survival (p = 0.032) and overall survival (p = 0.011) exclusively in the ER-positive breast cancer population. Conclusions. Cumulatively, our findings suggest that GN might serve as an important prognostic factor for ER-positive breast carcinoma.