SOX2 and ovarian serous adenocarcinoma: On the other hand, recent studies suggest an important role of the transcription factor SOX2 in maintaining the cancer stem cell state of ovarian cancer cells: in fact, in serous ovarian cancer cells SOX2 expression increases the expression of cancer stem cell markers, the potential to form tumor spheres in vitro and the tumorigenic potential in vivo; furthermore, SOX2-expressing ovarian cancer cells display enhanced resistance to apoptosis induced by chemotherapy or by cell death inducing agents, such as TRAIL [255].