Sherman-Samis M, et al. - In in high-grade serous carcinoma (HGSC), researchers examined the expression, biological role and clinical importance of cancer stem cell markers. In 134 HGSC specimens, mRNA expression of NANOG, OCT4, SOX2, SOX4, SOX9, LIN28A and LIN28B has been analyzed by qRT-PCR. In 52 HGSC effusions, Nanog, OCT3/4, SOX2 and SOX9 protein expression by immunohistochemistry was analyzed. In vitro, Nanog knockout suppresses reduced migration, invasion and MMP9 activity. Findings suggested that HGSC effusion levels of SOX2 and SOX9 mRNA may be clinically aggressive disease markers. In effusions, Nanog is secreted in HGSC exosomes and modulates cellular processes that promote tumors in vitro.