NANOG and ovarian cancer: Importantly, these exosomes contain unique protein signatures specific to ovarian cancer, including membrane proteins (Alix, TSG 101), small GTPases (Rab proteins), annexin proteins, tetraspanins (CD9, CD82, CD63 and CD81), heat shock proteins (Hsp90, Hsc70), antigens (MHC I and II), Nanog and enzymes (phosphate isomerase, peroxiredoxin, aldehyde reductase, fatty acid synthase) (Fig. 1b).