Overexpression of SOX2 is associated with poor prognosis in human breast cancer

SOX2 is a transcription factor that activates or suppresses genes involved in cellular differentiation, proliferation, and apoptosis. The deregulation of gene expression programs can lead to cancer initiation, promotion, and progression. The present study investigated SOX2 immunolocalization and expression in Invasive Ductal Carcinoma (IDC), and its correlation with clinical-pathological characteristics of the tumor. Immunohistochemical expression of SOX2 was evaluated in 19 cases of IDC and correlated with clinical-pathological tumor features. To investigate the correlation of SOX2 expression in IDC with other characteristics of human breast cancer, the same samples were also stained with immunohistochemical prognostic panels (estrogen and progesterone receptors, and HER-2). SOX2 overexpression was observed in 44% of the cases. Higher SOX2 expression was correlated with the worst lymph node status (p<0.001) and with positive HER-2 immunostaining (p<0,001). The present study demonstrated the association of SOX2 and tumors with worse TNM staging, as well as its overexpression in positive HER-2 tumors. In conclusion, SOX2 was identified as a potential biomarker for poor prognosis of human breast cancer. Further studies with higher patient numbers are necessary to investigate and help clarify the mechanisms underlying this association.