CD44 and ovarian cancer: Compared to the scrambled control cells, EGFL8 silencing via siRNA increased the expression of the common ovarian cancer stem cell (CSC) markers CD44, CD117, and CD133 and four major pluripotent stem cell transcription factors, sex-determining region Y-box 2 (SOX2), octamer-binding transcription factor-4 (OCT4), homeobox protein NANOG transcription factor (NANOG), and Krüppel-like factor 4 (KLF4) in human OC cells (Figure 8A).